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EUROPE NEEDS A CLEAR COMMITMENT TO ITS HYDRO POWER A tool is only as good as the way it is used. The best current example of this is the trading of CO2 emissions certificates. This was launched in 2005 with the aim of protecting the climate and championing the expansion of renewable energies. The idea behind this was fundamentally an excellent one. Across the EU, a stipulated number of certificates, as it were "pollution permits", were issued. The intention was that the trading of them on the free market would create market-based incentives for industry and the fossil energy sector to invest in technologies which help to preserve the climate. But in particular the economic crisis since 2008 has thwarted the entire concept. The volume of certificates in circulation since this time became too high – and became inflationary. Whereas the EU Commission originally expected a price of around 30 euros per tonne of carbon dioxide, today the price has now fallen to below 3 euros. This price drop has various consequences. The most precarious of these is undoubtedly that an increase in carbon dioxide emissions in the area of the EU is once again being seen as a result. This is not the end of the paradoxes: in parallel this situation is massively oppressing the expansion of renewable energies, which is the exact opposite of the purpose of certificates trading as a tool. At present, coal-fired power stations are experiencing a real renaissance, particularly in Germany but also in other EU countries. The low price for the CO2 certificates is making the generation of power from coal lucrative once more. This aspect in particular brings with it a whole host of disadvantages for the renewable energies sector. First of all, a number of countries were intending to fund investments in an energy turnaround by auctioning off CO2 certificates. Secondly, the low emissions trading prices are making the reallocation charges for renewable energies more expensive, which will undoubtedly have a negative impact on the level of acceptance within the general population when it comes to the expansion of green energy plants. It is having an extremely negative impact in particular on those forms of energy which in many places can rely on no or only low funding subsidies – as is the case with hydro power in a number of countries. And hydro power operators in particular are increasingly coming under economic pressure. Ultimately, they are also expected to implement the specifications from the European Water Framework Directive. The low direct revenues from the lower market price are frequently no longer adequate to make it economically viable to make the necessary adaptations to a facility, let along to construct a new facility. There is a need for political action. As recently as last autumn, the European Commission proposed withdrawing 900 million emissions certificates from the market in order to bring about an increase in the prices and thus to bolster emissions trading as a tool for climate protection. But this proposal was rejected by the EU Parliament in mid-April. The basic thrust of the argument put forward by those members of parliament who voted against the measure can be summed up in the following sentence: "There must be no intervention in the free market." In the end, it was nothing short of a disastrous signal to send to all of the participants in emissions trading. In particular for small and medium-sized players in the hydro power industry in Europe, this means that improvements in the market prices can scarcely be expected in the foreseeable future. The need for politicians to take action at both a national and EU level is therefore all the more urgent, in order to create a general economic framework for Europe's small-scale hydro power operators to work within. Due to the excellent level of availability, efficiency and not least the good environmental compatibility, hydro power is still regarded as the focal point for renewable forms of energy and it also harbours a valuable legacy with regard to electrifying the regions. Particularly under these premises, political support both from Brussels and at a national level would be most welcome. Finally, I would like to thank all those who have contributed to the production of this edition of zek HYDRO – above all our lady in the office, Erika Gallent, whose excellent work coordinating the translations was the key to our being able to release this publication on schedule. My thanks also go to the team at ESHA, to the President, Marko Gospodjinacki, and the General Secretary, Dirk Hendricks, for the great support provided as part of our media partnership. I wish all our valued readers an enjoyable and informative time reading the latest edition of zek HYDRO. Best regards, Roland Gruber Editor-in-Chief April 2013

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For over 4 ฀years we have been developing efficient and sustainable technologies for producing energy from hydropower while stressing innovation and workmanship in the manufacture of our systems. More information at www.elektroanlagen.at

WATER FLOWS CONSTANTLY ONWARDS. OUR TECHNOLOGY TOO.


HYDRO

26 PP MÜHLBACH (IT) 08

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short news out of the world of hydropower

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Editorial Table of Content Masthead

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April 2013

PP LAPAJ (AL)

40 PP LINTHAL (CH)

54 PP NÖTSCHBACH (AUT)

16

Why does SHP need bigger presence in Brussels? [ ESHA-NEWS ]

38

Red-white-red „Nervous System“ for exemplary power plant [ ALBANIA ]

18

More than half of EU’s small hydropower potential is untapped [ ESHA-NEWS ]

40

Construction site of the century at pumped-storage project [ SWITZERLAND ]

19

The revitalization of the small hydropower in Europe [ ESHA-NEWS]

45

Moessmer opens new chapter in hydropower utilisation [ ITALY ]

20

Successful and unconventional dinner in the EU parliament [ ESHA-NEWS ]

50

Glacier Water drives new Power Plant at Vernagtsee [ ITALY ]

22

Austrian Hydro Technology proves itself in the Apennines [ ITALY ]

54

Austria’s first Mine-Mouth PP is mining Eco-Power [ AUSTRIA ]

26

Private pioneer project optimises power generation for community [ ITALY ]

58

Small hydropower plant with Ossberger cross-flow turbines [ CHILE ]

32

Output doubled at long- serving Budweis Power Plant [ CZECH REPUBLIC ]

60

Model Power Plant created in the heart of the town Celle [ GERMANY ]

35

Inauguration for prestigious Power Plant Lapaj [ ALBANIA ]

62

Turbine Power from Upper Austria for a Power Plant Chain [ ROMANIA ]


HYDRO

PP ISENTHAL (CH)

63

PP NEUMÜHLE (AUT)

86

SHUT-OTT DEVICES

Additional machine units for the Isenthal Power Plant [ SWITZERLAND ]

88

66

EVN completes model project in sensitive area of Mürz river [ AUSTRIA ]

90

DN400 PN85 for artificial snow in South Tyrolean Ried [ PIPE TECHNOLOGY ]

70

37-Ton power units heaved into a Power Plant in Salzburg [ AUSTRIA ]

92

Grison-based valve specialst for safe hydropower plants [ TECHNOLOGY ]

72

Green City Energy enables participation in French SHPP [ ECONOMY ]

94

When shut-off devices need a makover [ TECHNOLOGY ]

76

Maximum yield at minimal cost in small-scale hydropower [ ECONOMY ]

98

Relying on hydraulic steel engineering from Muhr [ TECHNOLOGY ]

80

Marked wear on the bearing of a Francis turbine [ TECHNOLOGY ]

100 The custom tailored trash rack cleaner [ TECHNOLOGY ]

84

Environmentally considerate lubricants for hydropower plants [ HYDRAULIC OIL ]

102 Braun’s biggest trash rack cleaner to operate in Salzburg [ TECHNOLOGY ]

86

Laying of DN3000 GRP FLOWTITE Pipes [ PIPE TECHNOLOGY ]

104 The trash rack cleaner - selection criteria and applications [ TECHNOLOGY ]

63

Monitoring and securing penstocks against rock depression [ PIPE TECHNOLOGY ]

94

TRASH RACK CLEANER

100

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April 2013

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HYDRO

UPGRADE FOR SOUTH TYROLEAN 1000-M HEAD POWER STATION Even in the Alps, high-pressure powerstations with penstocks of over 1,000 meters are considered exceptional. A high-pressure power plant was constructed in the municipality of St. Leonhard im Passeiertal in 1993. With a penstock of 1,060 meters ,the Gomion power plant belongs to the elite "1000-metre club". In 2010/2011 the power station underwent a comprehensive upgrade. The company mainly responsible for this was Troyer AG of South Tyrol, who not only replaced the turbine, but also brought the temperature control bang up to date. In all, the small energy provider from the Passeiertal invested approximately 2 million euro in the upgrade of the high-pressure power plant. With the new 960-kW Pelton turbine, the power plant now generates around 3.5 to 4 million kWh of clean electricity in a standard year.

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April 2013

PUBLISHERS Mag. Roland Gruber and Günter Seefried PUBLISHING HOUSE Gruber-Seefried-Zek Verlags OG Lindaustraße 10, 4820 Bad Ischl

photo credits: zek

Tel. & Fax +43 (0) 6247- 84 726

Successful replacement of the hydropower set in the power plant of Swiss company Daniel Jenny & Co.

office@zekmagazin.at www.zek.at EDITOR-IN-CHIEF Mag. Roland Gruber, rg@zekmagazin.at Mobile +43 (0)664-115 05 70 EDITOR

photo credits: Haider

GEBRÜDER HAIDER COMPLETES ANOTHER POWER STATION IN ROMANIA Having commissioned their first hydroelectric power station on the Budac in the Romanian province of Transylvania in 2011, the Gebrüder Haider group of companies followed it up with number 2 last year. In only eight months, the experienced power plant constructors from Austria completed the new high-pressure plant which generates almost three times the amount of electricity of the Budac I plant. The 6-nozzled Pelton turbine (manufactured by Andritz) with an installed capacity of 2.2 MW will supply the Romanian electricity grid with roughly 7 million kilowatt hours per year. For the Gebrüder Haider group of companies, a long-established, reliable general contractor in the field of hydroelectric power stations, this represents an important step in the Romanian hydropower market. Budac III is already in the pipeline.

Masthead

Thomas Mott, tm@zekmagazin.at Mobile +43 (0)664-22 82 323 MARKETING Günter Seefried, gs@zekmagazin.at Mobile +43 (0)664-3000 393 ADMINISTRATION Erika Gallent, office@zekmagazin.at Mobile +43 (0)664-242 62 22 TRANSLATION CPC | Crossing Paths Communications Mag. Andreas Florian, office@crossing-paths.net Mobile +43 (0)664-217 40 90 Reinhard Fischer, ReinhardFischerOffice@gmx.net

The Gebrüder Haider group of companies has now completed its second power station on the Budac River in the Romanian province of Transylvania.

PRODUCTION, PDF CREATION MEDIA DESIGN: RIZNER.AT Stabauergasse 5, 5020 Salzburg Tel. +43 (0) 662 / 87 46 74 E-Mail: m.maier@rizner.at PRINTING Druckerei Roser Mayrwiesstraße 23, 5300 Hallwang /Salzburg Tel. +43 (0) 662-661737 POST OFFICE A-4820 Bad Ischl BASIC GUIDELINES

photo credits: GOMION

REPLACEMENT MACHINE IN SWISS TEXTILE FIRM BRINGS PERFORMANCE BOOST Daniel Jenny & Co, a renowned textile company located in the Swiss town of Haslen an der Linth, has been in operation for more than 170 years. Now, the existing, 107 years old turbine is going to be replaced by hydrospecialists Andritz Hydro and the power plant given a new lease of life. The new hydropower set, consisting of a double-regulated Kaplan turbine and a directly coupled synchronous generator (manufactured by Indar), will generate around 6 million kWh in a standard year. This is set to raise annual production by 75 percent.

Gomion Power Plant, South Tyrol, has been in operation since 1993 and is one of the few high-pressure power stations with a penstock of more than 1,000 meters. The machinery was replaced two years ago.

zek HYDRO is a non-partisan trade publication focussing on hydropower. PRICE INC. POSTAGE € 12,– / copy inc. VAT zek HYDRO is published annually Circulation: 5,400 copies


essential.

MarelliMotori www.marellimotori.com


photo credits: Nalcor Energy

HYDRO

Over the next few years, four power plants with a total output of 750 MW are to be constructed along the river Drina.

photo credits: zek

The Obermatt power plant has been supplying the city of Lucerne and the well-known mountain village of Engelberg with electricity for over 100 years

photo credits: Cornus

Muskrat Falls is located on the Churchill River, 35 kilometers from Happy ValleyGoose Bay. Some of the power will be exported from the province via subsea cables between Newfoundland and Nova Scotia.

ANDRITZ HYDRO SUPPLIES EQUIPMENT FOR MUSKRAT FALLS HPP ANDRITZ HYDRO has received an order from Nalcor Energy to supply four 209 megawatt (MW) Kaplan turbines and four synchronous generators for the new Muskrat Falls hydropower plant in Labrador, Canada. Commissioning is scheduled for 2017. The power generated will be used to replace the energy production of an oil-fired thermal power station. The order has a value of approximately 125 million euros. ANDRITZ HYDRO’s scope of supply includes design, manufacturing, installation, commissioning, and testing of the Kaplan turbines, which are among the largest in the world, the four generators, as well as governors, static excitation systems, and the monitoring, protection, and control equipment. The turbine engineering is based on the hydraulic developments at ANDRITZ HYDRO’s turbine laboratory in Lachine, Quebec, the only hydraulic development and test facility of its kind in Canada. FOUR NEW HYDROPOWER PLANTS IN THE REPUBLIC OF SRPSKA RWE Innogy, the Republic of Srpska - a constituent republic of Bosnia and Herzegovina and the state-run energy provider Elektroprivreda Republike Srpske (ERS) have formed a partnership in Banja Luka for the development, construction and operation of four hydroelectric power stations. RWE Innogy was previously selected as part of a call for tenders. In the coming years, project companies will survey and develop four hydroelectric power stations with a total of capacity of 210 MW along the river Drina. Following a positive outcome to the feasibility studies and completion of the planning process, construction of the first hydroelectric power station could commence in 2014. The chain of hydroelectric power plants should then produce around 750 gigawatt-hours (GWh) of electricity per year. NEW TURBINE FOR CONVENTIONAL SWISS POWER STATION For over 100 years, the Obermatt power plant in Engelberg has been an important source of energy for the city of Lucerne. Up until a year ago, the central building housed five hydroelectric sets. In 2010, the South Tyrolean turbine manufacturer, Troyer AG, was appointed to replace two of these machine units dating from the 1940s. The two old turbines have been replaced by a 4-nozzled Pelton turbine, which with a penstock of 312.5 m is designed with an installed capacity of 8 MW. Special attention was paid to protecting the listed buildings throughout the renovation project. Together with the directly coupled synchronous generator from LDW (Lloyd-Dynamowerke), the new hydropower set will generate around 60 GWh of the total annual capacity of 130 GWh. This is an important technical development for the conventional Swiss plant.

Hydropower for the future !

Wiegert GmbH ࠮ Turbines and Hydraulic Steel Constructions ࠮ Im Muhrhag 3 ࠮ 77871 Renchen iieeegge gerrtt & Bähr Maschinenbau Maassccchh M h n ࠮ Germany maa y m info@wb-hydro.de www.wb-hydro.de ࠮ phone +49 7843 9468-0 iinf in nnfo@ nf ffoo@ o@ @w w ddee ࠮ w ww ww

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April 2013


HYDRO

The new Ashta power plant is also considered to be an ecological showcase as it includes the first fish ladder to be built in Albania.

www.bhm-ing.com

photo credits: VERBUND

OVERALL ENGINEERING & C O N S U LT I N G S E R V I C E S

Power Plants r

VERBUND AND EVN COMMISSION A HYDROELECTRIC POWER PLANT IN ASHTA, ALBANIA Project company "Energji Ashta" and its owners VERBUND and EVN opened a world first in Albania on 18th September 2012: the largest matrix hydroelectric power station formed of many small-scale turbines. The Ashta hydroelectric power plant has been constructed over the last 30 months in the north of Albania near Shkoder, the fourth largest city in the country. It is the largest investment in the Albanian energy market in the last 30 years. An extremely innovative approach has been applied to the Drin river: The matrix technology (a small-scale turbine the size of a telephone booth) enables a particularly efficient use of the hydropower. The total capacity of both power stations (Ashta 1 and Ashta 2) is 53 MW; 240 million kilowatt hours are expected to be generated per year. This will provide 100,000 Albanian households with renewable energy. The volume of electricity generated is approximately equal to a quarter of that supplied by the Freudenau power station located on the Danube near Vienna. Construction began in March 2010. In all, the operators have invested around 200 million euro in the project.

r r r

photo credits: Kössler

The new Kissakoski power plant located along the canal of the same name replaces two old ones from the 1940s. The power plant has been fitted with an innovative Kössler bulb turbine and will generate about 9 GWh in a standard year.

EQUIPMENT FROM LOWER AUSTRIA DESTINED FOR FINNISH REFERENCE POWER PLANT The builders of the new Kissakoski power plant in the south-west of Finland have placed particularly high demands on the properties of their turbine. Not only should it be efficient and robust, it should also be able to cope with an extremely wide variability in operation. The solution to these extraordinary requirements in terms of the large variation in the water supply and penstock was provided by Kössler from Lower Austria. The specifically designed bulb turbine with integrated generator was installed at the beginning of last year. The machine is capable of guaranteeing efficient operation, both in fluctuating water quantities and with a varying penstock of between two and six meters. At a rated speed of 187.5 rpm, the machine is designed with an installed capacity of 1.5 MW. The new power plant will produce approximately 9 GWh of clean electricity per year. It will replace two old conventional power plants dating from the 1930s or 1940s. An industrial museum has now been created in which it is possible to marvel at the historic hydropower technology.

Europaplatz 4, 4020 Linz, Austria Tel. +43(0) 732-34 55 44-0 office.linz@bhm-ing.com, www.bhm-ing.com Bahnhofgürtel 77-79, 8020 Graz, Austria Tel. +43(0) 316-84 03 03 office.graz@bhm-ing.com, www.bhm-ing.com FELDKIRCH ‡ LINZ ‡ GRAZ ‡ VIENNA ROTTENMANN ‡ SCHAAN ‡ PRAGUE

April 2013

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HYDRO

BAVARIAN COMPANY BUILDS TURNKEY HYDROPOWER STATION IN RWANDA The two Bavarian companies F. EE GmbH and Kochendorfer Wasserkraftanlagen have merged to form Kochendorfer & F. EE Hydropower GmbH to get a foothold in the African energy sector. In the context of an international tender process the new company was able to prevail against six international competitors and was awarded the contract for the turnkey construction of the Rukarara II hydroelectric power station in Rwanda. The approximately 8 million euro hydropower project has an installed total capacity of 2.5 MW (Megawatt) and the set of turbines in the plant consists of two identical Francis spiral turbines manufactured by Austrian turbine specialist Kรถssler. The project is financed by the European Union, Belgium and Rwanda itself, the contract having been issued by the Rwandan Ministry of Infrastructure. photo credits: Alpiq

photo credits: Kochendรถrfer & F.EE

Construction of the powerhouse for the Rukarara II hydroelectric power plant in the East African country of Rwanda.

photo credits: Christian Helmle

The Ruppoldingen hydroelectric power station has been generating ecologically valuable electrical energy on the River Aare near Boningen for over 12 years.

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April 2013

ALPIQ SUPPORTS ENVIRONMENTAL PROJECTS ALONG THE RIVER AARE The Ruppoldingen hydropower plant belonging to Alpiq Hydro Aare AG has been certified with the "naturemade star" label since 2010. A considerable part of the added value from the generated ecological electricity flows into a fund. The money is earmarked for projects intended to ecologically enhance the natural environment in the catchment area of the river power stations at Flumenthal, Ruppoldingen and Gรถsgen. Several projects have already been completed, such as the creation of a wetland biotope in the Grenchner Witi, the restoration of the Chriziweiher pond in Biberist and Fischweiher pond in Trimbach, and the construction of two carp ponds in Rothrist and Brittnau. The Barnerschache shallow water areas below the Flumenthal power plant were also restored last autumn. The fund is also financing the design of a new tributary of the Aare river near Selzach. It has currently approved a total of approximately 900,000 Swiss francs for the executed projects and the planning and implementation of further project ideas. HYDRO-ELECTRIC POWER STATIONS ARE CONSIDERED CATHEDRALS OF TECHNOLOGY Christian Helmle's photographs are strikingly beautiful and are inspired by architecture or technology. But the impressive and powerful form of the sometimes gigantic hydro electric structures presented in the illustrated book "Waterpower" by the photographer from Thun in Switzerland and published by Jovis Verlag in Berlin is only really expressed in connection with the landscape that surrounds them. The use of hydropower in the Alpine region manifests itself in many architectural forms: power plants, dams, reservoirs and associated buildings self-confidently testify to a long tradition of generating energy with water along the Alpine rivers and represent strength, power, durability, reliability and richness. The most historic hydroelectric power stations are presented as cathedrals of technology in the artistic photographs in Christian Helmle's illustrated book and thus also bear testament to the engineering talent of the respective epochs. The power station structures illustrate the architectural currents of different decades of the 20th century. Evidence of palace architecture and the Heimat movement can be found along with that of New Objectivity. The photos portray the combination of architecture, technology and landscape and attempt to trace the development of energy architecture. The buildings are divided according to the four major river basins of the Alps: Danube, Po, Rhine and Rhone. The chapters are connected by pictures illustrating the individual local and poetic images of abstraction in progress.


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HYDRO

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photo credits: Deutsche Bahn AG

HYDRO

Deutsche Bahn is planning a steady expansion of the proportion of green energy it uses in the coming years.

photo credits: Siemens

photo credits: Voith

Interior view of the impeller of a Voith Hydro Francis turbine.

The Štetí hydroelectric power station on the banks of the Elbe river in northern Bohemia is expected to go into operation in July 2014.

photo credits: VERBUND

Wolfgang Anzengruber was re-appointed to his office as Chairman of the Board of Management of Verbund AG for a further 5 years .

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April 2013

DEUTSCHE BAHN INCREASES THE SHARE OF ITS ELECTRICITY SOURCED FROM HYDROPOWER The German Railway company Deutsche Bahn AG and E.ON AG have signed a long-term contract for the supply of green electricity from hydropower for rail transport in Germany. From 2015, E.ON will supply DB with 600 million kWh of green electricity per year. This is equivalent to a 5% share of the traction power mix of DB Energie, Deutsche Bahn's energy provider. From 2015, the share of renewable energy will thereby increase to over 26%, while CO2 emissions will drop by 313,000 tonnes per year. The green power will be supplied from the E.ON hydroelectric power stations on the Main, Danube, Lech, Isar and Inn and by 2020, green power will account for over 35%. In Germany, E.ON is one of the largest suppliers of hydroelectric power and annually generates around 8 billion kWh of green electricity in more than 100 plants. VOITH HYDRO MODERNISES TURBINES FOR NORWAY'S LARGEST ENERGY COMPANY STATKRAFT Voith Hydro is going to modernise six turbines in four Norwegian hydropower stations for Norway's largest energy company Statkraft. The recently signed contract is worth around 10 million euro. As part of the new contract, the turbines installed between 1955 and 1975 in the Oevre, Roessaaga, Nedre Roessaaga, Baatsvatn and Vessingfoss power stations will be replaced by six new Francis turbines and will add up to 10 per cent more output in the future. "The contract in Norway is a major success for Voith," said Dr. Roland Münch, Chairman of the Management Board of Voith Hydro. "We are working very well together with out customer Statkraft in the most important hydropower market in Europe." Norway is the sixth largest hydroelectricity producer in the world. SIEMENS RECEIVES ORDER FOR TWO GEAR UNITS FOR EUROPE'S LARGEST KAPLAN PIT TURBINES The Siemens Drive Technologies Division has received an order from Voith Hydro GmbH & Co. KG, Austria, to supply two gear units for the Šteti hydro power plant in the Czech Republic. The gear units will be used in Europe's largest Kaplan bulb turbines in pit design. The special feature of the gear units is that their shafts are arranged horizontally one above the other. They are the biggest Flender gear units ever made for this special mounting position. Through the gear unit, the existing turbine speed will be increased from 64 to 750 revolutions per minute. The three-blade Kaplan bulb turbines have a runner diameter of 5.1 meters. The Štetí hydro power plant will feed approximately 30 gigawatt hours of electricity generated from renewable energy sources into the grid every year and will thus reliably supply power to 12,000 households in the region. VERBUND AG: NEWLY APPOINTED EXECUTIVE BOARD In its meeting of 5th March 2013, under the chairmanship of Dr. Gilbert Frizberg, the Supervisory Board of the listed company Verbund AG appointed the four publicly advertised Executive Board positions for a period of five years. Three of the current members of the Verbund AG Executive Board were unanimously reappointed for the 5-year period from 1st January 2014. These are Wolfgang Anzengruber as Chairman, Johann Sereinig as Deputy Chairman of the Executive Board and Günther Rabensteiner as Executive Board member. Peter Kollmann was also unanimously appointed Chief Financial Officer. The 50-year-old Austrian worked in Vienna and in London immediately after completing his studies. Most recently, he’s been acting as Vice Chairman Corporate & Investment Banking EMEA at Merrill Lynch since 2006 .


graphic: Bielersee Kraftwerke AG

HYDRO

The improved flood protection of the modernized Hagneck plant is also expected to cope with 1 in 1000 year floods of Lake Biel.

FIRST STAGE OF CONSTRUCTION OF THE NEW HAGENECK HYDROPOWER PLANT COMPLETE In 2012, Bielersee Kraftwerke AG, half owned respectively by the City of Biel and BKW FMB Energie AG, completed the first of a total of four years of construction involved in the renovation of the Hagneck hydroelectric power station. The plant, built in 1898, is now obsolete has to be upgraded. Specifically, the high-water capacity of the weir no longer meets today's needs, as proven by the floods of August 2005 in particular.

The reconditioned, modern power plant will increase production by 35 per cent without damaging the environment. The Hagneck hydroelectric plant is located on protected pasture land, so the environmental impact of the plant was given high priority during the comprehensive upgrade. The project also meets with great interest from the public. Since the ground-breaking ceremony, 2,300 people have visited the construction site to find out about the construction of the new plant. The modernised Hagneck power plant is expected be put into operation in the summer of 2015.

Competency for Small Hydro Kรถssler turns Water into Power. We develop innovative, standardized solutions that ensure high economy in the generation of electricity from hydro power for our customers. Our optimum price-performance ratio results from the application of state-of-the-art technologies and our targeted orientation on the specific requirements of the operators of

small hydro power plants: Clearly defined scope of delivery, high availability, trouble-free operation, low operating costs and fast pay-back period. www.koessler.com A Voith and Siemens Company

April 2013

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HYDRO

photo credits: Rolf Handke_pixelio.de

ESHA relies on the support of individual organizations and companies to strengthen and defend the community in Brussels.

EU-Building in Brussels

WHY DOES SHP NEED BIGGER PRESENCE IN BRUSSELS? Even so the European Union and Brussels do not seem to have much to do with the daily business of small hydropower stakeholders in EU member states, EU policy processes and legislation directly impact the small hydropower business on national and local level since EU regulations become immediately enforceable in all member states and directives (for example the Water Framework Directive and the Renewable Energy Directive) need to be transposed into national law.

F

urthermore, several non-EU countries like Norway and Switzerland typically use EU policies as a starting point for their own regulations. And representatives of EU institutions and member states advocate their positions and policy priorities in international organisations such as the United Nations or IRENA. In addition, EU member states tend to distribute aid to developing countries based on their own national policies for energy. In short, if the EU as such favours the development of small hydropower within its territory, they will most likely support it also outside Europe. The EU agenda for 2013 and 2014 includes a number of topics which can have a positively or adversely impact on the future deve-

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April 2013

lopment of the small hydropower sector in each member state. They therefore need to be closely monitored and influenced by the SHP sector.

SHP HAS TO REMAIN AN IMPORTANT PART OF EU’S RENEWABLE ENERGY MIX The development of a Common Implementation Strategy of the European Water Blueprint offers a chance to erase discrepancies between the RES and WFD directives. At the same time, there are discussions about a mandatory Strategic Impact Assessment for each new hydropower plant which would significantly increase its development costs. The SHP sector needs to ensure that discussions and future decisions on the necessity of

support schemes; the future shape and rules of a European internal energy market; the future grid infrastructure; and the planned Directive on the Awarding of Concessions are in favour of the sector’s long-term development. The revision of the RES Directive in 2014 as well as the final EU Energy Roadmap 2050 need to be used to ensure that SHP will be an equally important component of the EU’s renewable energy mix which member states promote now and in the future. ASSOCIATION PROVIDES SUPPORT With 24 years of existence, ESHA is known as an influential and vibrant advocacy organisation which can proudly look back at important political and organisational achieve-


HYDRO

ments. Given the current and upcoming political developments and processes on EU and member states level, ESHA’s reputation, status and activities ensure that the interests of the small hydropower sector are taken into account. ESHA’s activities in working groups, conferences, events and bilateral meetings with EU officials and parliamentarians maintain the necessary contacts and networks to keep the advantages, potential and opportunities of small hydropower in the awareness of key EU decision-makers. The association also provides support to several national SHP associations. An ESHA organised conference in Bucharest last year helped to positively influence Romanian law concerning SHP development. Poland is on the verge of withdrawing the feed-in tariffs for SHP which might significantly hinder the local SHP market by bankrupting 450 of the 700 existing power plants. ESHA lobbies Commission officials to lean on the Polish Government to maintain the existing support scheme against this new legislation.

photo credits: Ben Götzinger

CHANCES FOR GROWTH ARE VERY GOOD Despite being in a difficult political and economical situation, the chances for a strong growth of the SHP sector in the mid-term

run are very good given the new market reality. Within the future market energy design hydropower is a key actor in enabling the production of non-variable, dispatchable, flexible and back-up electricity which will become more important in the coming years. To use this exceptional opportunity, the SHP sector needs endurance and a strong long-term engagement for the upcoming long-lasting consultation processes within EU institutions.

„WE NEED A LOUD VOICE“ In this respect, a strong and stable representation is a prerequisite for successful lobbying. Having a large network of members and their support allows ESHA to run more campaigns and to have a greater capacity to influence the

thousands of pages of potential legislation being written on the European level. By bringing together the entire SHP industry from national associations, power plant owners to equipment manufacturers, ESHA is able to present a unified strong message to policy makers. The more members ESHA has, the louder the voice of the SHP sector. The louder this voice is, the greater the ability to influence policy makers. The greater our influence, the more business opportunities for you! ESHA relies on the support of individual organizations and companies like yours to strengthen and defend our community. In addition to influencing policy makers, ESHA seeks to maintain a strong network within the industry by holding international conferences and workshops. Help protect the future of the small hydropower industry by supporting ESHA.

European Small Hydropower Association Rue d’Arlon 63-67 1040 Bruxelles, BELGIUM www.esha.be T: +32 2 400 10 67 E: info@esha.be

istan bu l, sp rin g 2014 April 2013

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Foto: GHE

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MORE THAN HALF OF EU’S SMALL HYDROPOWER POTENTIAL STILL UNTAPPED For the past ten years, small hydropower potential has been greatly affected by environmental legislation that falls under designated areas such as Natura 2000 and the Water Framework Directive. For some countries, the small hydropower economically feasible potential was reduced by more than a half. Yet, there is still a large potential for small hydropower development in the EU-27.

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ess than half of the potential has already been tapped - some 44 TWh/year. More than 50 TWh/year can be put on line in the future, if the current conditions are improved. Thus, small hydropower must be designed site by site in order to comply with all the environmental requirements to take advantage of the remaining potential. According to the European Commission’s IEE programme co-funded project STREAM MAP, the most promising countries for SHP further expansion in the EU are Italy, France, Spain, Austria, Portugal, Romania, Greece and Poland.

DIFFERENT FROM OTHER RENEWABLE TECHNOLOGIES “It is beyond any doubt that the European hydropower industry is quite mature and highly developed at technological level. Nevertheless, the whole hydropower sector requires stable policies and regulations, both at national and EU level, for its development”, emphasizes European Small Hydropower Associations’ Secretary General Dirk Hendricks. The sector can be financial-

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ly sustainable if fair market rules are provided - financial schemes for hydropower projects should account for multipurpose features of hydropower, not only production of green electricity, but also its incomparable high efficiency, its contribution to grid stability, and other benefits related with water resource management, as flood protection. In fact, small hydropower has specific characteristics that are quite different from other renewable technologies, like time availability of the resource, long life time (up to 100 years) and the multipurpose use of water. However, like other renewables, small hydropower needs regulatory stability and fair market rules, especially concerning permit granting, technical rules and in the financial environment (tariffs).

TRANSPARENT CRITERIA FOR THE LICENSING PROCEDURE It is also important to recall that the licensing procedure for small hydropower is a time consuming and bureaucratic procedure as numerous permits are necessary to be issued. On top of that, most of the time this process

is dependent on poorly coordinated entities from different public authorities. Therefore, the future licensing should rely on simple, fair, solid and transparent criteria suitable with small hydropower scale promoting a faster, and more predictable result in the outcome. To find out more, consult the up-to-date hydropower database and now available Roadmap, at http://streammap.esha.be/ or visit the European Small Hydropower Association at www.esha.be


photo credits: Susannehs_pixelio.de

photo credits: Katharina Wieland M端ller_pixelio.de

photo credits: Dieter Sch端tz_pixelio.de

photo credits: Roger Mladek_pixelio.de

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THE REVITALIZATION OF SMALL HYDROPOWER IN EUROPE Small hydropower is an ecologically sustainable and important part of our renewable energy mix. It contributes significantly to stabilizing electricity production throughout Europe. Investing in local small hydropower projects means support for (often deadbeat) municipal finances. It reduces the dependency on external energy supply and preserves the environment and our historic heritage.

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here is a huge, unused potential of small and micro hydropower in Europe's many historic mills, water wheels, shut-down hydropower plants, weirs and diverted river arms. With the renovation of shut-down hydropower plants electricity is produced for local needs and to provide additional supply to the European electrical grid. This results in higher electricity output from renewable sources, reduced energy dependency and higher grid stability.

The 'RESTOR Hydro Map' gives helpful information on the hydropower potential of historic plants in Europe (EU-27). Free access to all information gathered is granted to regional boards, municipalities, local hydropower operators and any person interested. The 'RESTOR Hydro Map' provides detailed information on the location and characteristics of up to 50,000 plants and in this way supports the development of projects and the foundation of energy cooperatives.

The RESTOR Hydro project comprises a consortium of eleven partners and is coordinated through the European Small Hydropower Association (ESHA). Its goal is to find ideal plants for renovation and put them on a map. With the development of a market-friendly model for regional cooperative projects, investment is stimulated.

A WIN-WIN SITUATION FOR THE REGION The RESTOR Hydro project creates guidelines for the development of small and micro hydropower cooperatives. In terms of financing these cooperatives help increase the chance of renovation projects being realized. An umbrella organization can administer one or more plants in a region. It can be responsi-

ble for evaluating the potential of plants and elaborating feasible financing plans for their renovation. Small and micro hydropower cooperatives keep municipalities going. The cooperative effort to produce decentralized energy strengthens the economy, enhances the security of energy supply and supports the environment. It is a win-win situation for the region. Renewable Energy Sources Transforming Our Regions (RESTOR) Hydro is a project cofinanced by the European Commission through the Intelligent Energy Europe program. For information on the foundation of cooperatives and on the development of small hydropower projects please go to http://www.restor-hydro.eu/ or contact ESHA at info@esha.be.

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photo credits: ESHA

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SUCCESSFUL AND UNCONVENTIONAL DINNER IN THE EUROPEAN PARLIAMENT TO BETTER KNOW SMALL HYDROPOWER On Tuesday 26th of March, the European Small Hydropower Association (ESHA) launched its Hydropower Campaign 2013 entitled “Getting to Know Small Hydropower”. ESHA organised an informative dinner and quiz in the European Parliament in Brussels, hosted by Member of the European Parliament Sir Graham Watson. Almost 100 people attended this special evening, including several Members of the European Parliament and high European Commission officials, and learned about the assets and the potential of this renewable technology. By Dory Moutran (ESHA)

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SHP SECTOR IS BEING THREATENED WITHOUT SUPPORT ESHA President Marko Gospodjinacki pointed out in his presentation that SHP’s strengths were numerous. Its capacity to balance the grid by allowing for effective flexibility makes it a key ally rather than a competitor of other renewable energy technologies. Gospodjinacki also presented several examples of European SHP installations, where technical solutions were found for the

further environmental improvement of hydropower installations. Nonetheless, it was also mentioned that without the EU’s interest in the sector, and without financial and legislative support, the small hydropower sector’s potential in Europe is being threatened. Finally, ESHA’s President invited all policy-makers to make decisions based on rational choice, and was confident that SHP would meet the required criteria to pass the tests.

ESHA President Marko Gospodjinacki (left) talking to Sir Graham Watson, host of the event and chairman of the Climate Parliament.

photo credits: ESHA

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he aim of ESHA’s new campaign is to put small hydropower back on the European energy map. As most recent discussions tend to focus rather on the challenges of phasing out conventional sources of energy, and on the progressive integration in the grid of emerging green energy technologies such as wind and solar, few eyes actually turn to hydropower. However, hydropower is a mature renewable technology of utmost importance for the RES mix. The “Getting to know Small Hydropower” campaign aims at showing both to the public and to the policy makers the benefits and potential of this technology. Among the participants were distinguished Members of the European Parliament from different countries and political parties such as Dr. Paul Rübig, Vittorio Prodi, Csaba Sogor, Antonio Correia de Campos and the event’s host, Sir Graham Watson. They took part in discussions, participated in the quiz and shared their views with representatives of the hydroelectric industry in Europe, representatives of the European Commission, and various participants coming from diverse backgrounds and sectors.


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photo credits: ESHA

photo credits: ESHA

ESHA President Marko Gospodjinacki pointed out in his presentation that SHP’s strengths were numerous.

Member of the EU Parliament Vittorio Prodi describing his view on the small hydropower sector.

of acquiring authorisation procedures, and measures to facilitate fish migration, etc. The final and most decisive question was to estimate the minimum number of small hydropower plants that are currently threatened by liquidation, should a recent revision of the Polish law on support schemes be fully implemented in Poland. The answers to most questions could be found in the “Small Hydropower Roadmap”, a report published in the framework of an EU co-funded project “Streammap”, coordinated by ESHA, which compiles energy, market and policy data on the small hydropower sector in the EU-27. Participants showed active participation in their attempt to answer all questions, as they were discussing SHP with their teammates and going through the pages of ESHA’s extensive publication.

THE DINNER WITH THE QUIZ The highlight of the event was probably the quiz, which was introduced by ESHA Policy Officer Oliver Jung: 10 tables played in teams and had to answer 14 questions on small hydropower. The winning table would be rewarded with bottles of champagne. Questions related to various topics such as the potential for growth of the technology in the EU-27, the lengthy administrative processes

DIFFERENT VIEWS ON EUROPEAN SHP After the answers to the quiz had been revealed, Ewa Malicka from the Polish Association for Small Hydropower Development (TRMEW) gave an emotional speech on the alarming developments in Poland. The country’s small hydropower sector, which struggles as in many EU countries, with already heavy administrative and legal hurdles, is now facing new legislations which would put an

photo credits: ESHA

ESHA Secretary General Dirk Hendricks (right) and Carlos Velasquez from the Latin American SHP organisation CELAPEH discuss collaboration between both regions.

end to financial and regulatory support schemes, without the possibility to regain them. She mentioned a study showing that about 450 out of the 760 small hydropower plants are currently in danger of going bankrupt. Before the results and the winning table were announced, some Members of the European Parliament attending the dinner expressed their views on small hydropower. This opened an interesting debate where participants were able to ask for more information on SHP or contribute with their own knowledge and experiences. UNCONVENTIONAL AND SUCCESSFUL The event was a huge success, and ESHA has received several praises and positive reactions on the organisation of this unconventional event. Several attendants claimed that the dinner allowed them to interact with people from different national and professional backgrounds, while the quiz increased the connections between individuals in their respective teams. The format of the quiz was also suitable to efficiently convey knowledge and information on small hydropower. What a memorable night, especially for the winning team awarded with bottles of champagne. This proves well that small hydropower is not only about water…

photo credits: ESHA

EUROPE NEEDS AN EFFICIENT ENERGY MIX Sir Graham Watson, host of the event and chairman of the Climate Parliament, a network of legislators working worldwide to combat climate change, stressed on the importance of having an efficient European energy mix which should help develop a stable European Supergrid. He mentioned that hydropower’s additional advantage was that many of its plants can serve as energy storage facilities. He also pointed out that although the need for storage is often debated, it was increased by the progressive integration of variable RES technologies into the grid. Watson said that pumped storage had proven to be the most efficient and technologically mature system to balance supply and demand of electricity, capable of generating electricity within minutes, even in case of power cuts.

Austrian Member of the European Parliament, Paul Rübig also attended the dinner.

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photo credits: zek

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Located over 1,000 meters above sea level, Ligonchio is the highest municipality in the Apennines. The district in the Tuscan-Emilian Apennines is characterised by sustainable tourism and use of the rich hydropower resources.

AUSTRIAN HYDROPOWER TECHNOLOGY PROVES ITSELF IN THE TUSCAN-EMILIAN APENNINES With around 25 MW of installed capacity in the form of four high- and medium-pressure power stations, the 900-soul municipality of Ligonchio in the Tuscan-Emilian Apennines is one of the region's hydropower hotspots. One of these power plants is the privately operated Ligonchio power station, commissioned in 1991. Last year, the plant underwent a comprehensive modernisation process including replacement of the electrical equipment, and the operators decided to use high-quality hydropower technology from Austria. While the turbines were supplied by Tyrolean hydropower specialist Geppert, the two new synchronous generators came from the well-known Upper Austrian manufacturer Hitzinger, which is leading the way with such machines in terms of new dimensions and sizes.

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here in high-pressure power stations since the 1920s and the plants have long been part of the historic backdrop.

POWER PLANTS HAVE BEEN CHARACTERISING VILLAGE DEVELOPMENT At the beginning of the 1920s, workers were drawn from the entire province of EmiliaRomagna to participate in the construction of the first hydroelectric power station at Ligonchio. The hydropower plant not only became a symbol of the spread of technology in the previously exclusively rural region, but also one of economic growth, which bought with it an increase in the population. This importance is reflected in the external appearance of the engine house. The building was

designed in an Art Nouveau style and today is considered to be a successful example of early industrial architecture. On a technical note, this engine house contains the central two power plants which process the waters of the Ozola on the one hand and the waters of the Rosendola on the other. Overall, the three hydroelectric sets have a total installed capacity of around 11 MW. Today, the conventional Enel plant is in operation. As is the slightly further downstream power plant Ligonchio Ozola, which is the main usage point along the Ozola. An 11.9MW vertical Francis turbine processes the water from a large reservoir which is fed by smaller side streams as well the Ozola. This power plant was built in 1928 and - just like photo credits: zek

It is most noticeably northern Italy's city dwellers who are increasingly taking their holidays in the secluded Apennine region in the province of Emilia-Romagna. There they are looking for and finding the peace and quiet and natural beauty of the extensive beech forests of the Tuscan-Emilian Apennines National Park where the municipality of Ligonchio is located. The region relies on sustainable tourism which has been steadily increasing in recent years. Ligonchio oozes the pure charm of a mountain village, and located over 1,000 meters above sea level, it is the highest municipality in the Apennines. And yet there is something else that characterises its appearance: hydroelectric power. Electricity has been generated

The two conventional power plants from the early 1920s have shaped the landscape and historical development of the Apennine village: the Ligonchio power plant (right) was built in 1991.

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The new "winter turbine" brings with it a massive increase in capacity. The Geppert diagonal turbine is designed for a capacity of about 1.1 MW and can be operated up to a load of 3 per cent. It drives a directly coupled Hitzinger synchronous generator designed for a power output of 1.4 MVA.

photo credits: zek

turbine" designed to meet periods of low water availability.

NEW POWER PLANT FROM PRIVATE INITIATIVE It was then many years later before further investment was made in the rich hydro resources of the region. It took almost 70 years after the commissioning of the first power plant before another hydroelectric power plant was built in the Apennine community - the lower level power station to the Ligonchio-Ozola power station, which today is simply known as the Ligonchio power station. In contrast to the other three power plants, it is a privately operated plant belonging to P.E.I. AG with headquarters in Como. The power station, which has been in operation since 1991, was designed to take the processed water directly from the upstream plant and channel it via a gravity sewer to a stilling basin. The steel penstock runs from here in a direct fall line to the central building, which, in contrast to the other two large engine houses, is located in a remote area difficult to access. The works water covers just under 45 meters before it reaches the two turbines installed in the engine house. At the time of commissioning, the installed vertical axis

Francis turbine had a rated capacity of 2,380 kW. Five years later, in 1996, a second, smaller turbine was installed. This 550-kW horizontal axis Francis turbine served as a "winter The new hydropwer set 2 with a Geppert Francis turbine and a Hitzinger synchronous generator. The turbine is designed with a rated output of 2.2 MW, while the generator has a rated apparent power of 2.6 MVA. With this output class, wellknown manufacturer Linzer has introduced a new size to the market, now also making the proven quality of the Hitzinger generators available to medium-sized power plants.

photo credits: zek

the first plant - its striking, complex architecture blends into the Ligonchio landscape. Over the following decades, the two power plants have dominated the development of the small Apennine village. In the same way as they initially contributed to the growth of the local population, the increasing level of automation, particularly during the late 1960s, led to a decrease in employment and subsequently to increased emigration.

DOUBLE-SIZED WINTER TURBINE Although after at least 20 years of operation the power plant could hardly be considered old, some parts of the electrical equipment no longer met today's standard of technology. For this reason, and to increase the profitability of the plant, the operator decided to replace the installed machines and the control and automation technology. The operators from northern Italy decided on the sophisticated machine technology from Austria. The two turbines were supplied by the Tyrolean company Geppert, which, in spite of the existing hydraulic and spatial conditions in the engine house, made use of a certain amount of leeway with regard to the type of turbines used. "The large machines could only be replaced by a vertical Francis turbine because of the structural conditions. With 2,300 kW, it is even slightly smaller in terms of performance than the previously installed model," explains Geppert's project manager Dipl. Ing. Christian Moriel. "The small horizontal axis Francis turbine has now been replaced by a diagonal turbine, which, thanks to its specific

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photo credits: Geppert

Lifting the circular pipeline

photo credits: zek

Foto: zek

photo credits: Geppert

Assembling the turbine housing

The control technology was supplied by the South Tyrolean company en-co.

Technical Data w w w w w w w w w w w w

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Flow Rate (total): 8.3 m3/s Machine 1: Diagonal Turbine Flow Rate: 2’800 l/s Rotation Speed: 500 rpm Generator M1: Synchronous Generator Current: 1’171 A Machine 2: Francis Turbine Flow Rate: 5’500 l/s Rotation speed: 500 rpm Generator M1: Synchronous Generator Current: 2’175,5 A Standard Capacity: approx. 5 - 5.5 GWh

April 2013

w w w w w w w w w w w

River: Ozola Manufacturer: Geppert Net Head: 45.0 m Turbine Output: 1’119 kW Manufacturer: Hitzinger Apparent Power: 1’400 kVA Manufacturer: Geppert Net Head: 45.0 m Turbine Output: 2’234 kW Manufacturer: Hitzinger Apparent Power: 2’600 kVA

properties, covers a much larger scope than the previously installed set. With a rated capacity of 1,100 kW, it is twice as large and now allows a larger total quantity of water to be processed, namely up to 9,000 litres/sec. But where the diagonal turbine particularly excels, is that the power plant is also capable of operating with very small amounts of water, as is often the case in the winter. This turned out to be the right choice when it was commissioned in December, as the diagonal turbine operated with a turbine opening of just 3 percent during the first night of operation."

STARTING OPERATION WITH A THROTTLED TURBINE The Geppert engineers faced a challenge even before construction began. It was necessary to ensure that the new turbines could be integrated without having to rework the engine house. According to Christian Moriel, even the dimensioning of the diagonal turbine required the use of every millimetre of space. The feedin of the larger "winter turbine" also required a larger cross-section, starting with the bifurcated pipe: DN1000 up from DN700. "Unfortunately, the owner was unable to obtain the necessary building permits in such a short period of time. So, as short-term measure, a pipe section was manufactured to make use of the existing DN700 butterfly valve in order to go into operation with the new turbine throttled," explains the Geppert expert. A further challenge faced by the Austrian machine suppliers was the delivery of the turbine and generator. This was not only due to the extremely steep and unpaved access route to the engine house, but also to the weight of the generator. The larger of the two weighed around 17.5 tonnes and therefore even required the overhead crane in the central building to be modified. PUSH IN A NEW DIMENSION This weight is by no means normal for a synchronous generator produced by the well-known manufacturer Hitzinger. Quite the contrary: the larger of the two Ligonchio generators (the BG136) is actually the first of this size that Hitzinger has constructed. It was produced as a result of the reaction of the long-established manufacturer from Linz to the demands of the hydropower market, which is increasingly demanding medium-capacity synchronous generators between 1.5 and 3 MVA. Up to now, the capacities offered by Hitzinger were lower than that and therefore designed for classic "low water" applications, but operators can now also count on the high quality of the Hitzinger generators in the medium-range class too. The manufacturer insists that no technological leap was required. It merely sought to transfer the high quality standards of the smaller machines to the larger ones. And in this they undoubtedly succeeded. These synchronous generators also score points in the medium-range class in terms of their robustness, operating smoothness, good reliability and high level of efficiency. They also transferred the patented control system for high continuous short circuit current, along with the additional complex isolation technology in order to


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MODERN CONTROL SYSTEM In concrete terms, the larger generator is designed for 2,600 kVA and driven at 500 revolutions per minute by the vertical Francis turbine. The smaller synchronous generator, which is coupled to the shaft of the diagonal turbine, has a rated capacity of 1,400 kVA. The specified upgraded capacity of the turbines in the hydropower set is 1,119 kW. The total installed rated capacity of the turbines is around 3,350 kW. In place of a hydraulic oil system, the control device for both machines uses the tried-and-tested electric drives produced by the company enco. The electrical engineering company from Ratschings in South Tyrol managed the upgrade of the electrical equipment and modernisation of the control system. It was necessary to replace the transformers, the low and medium voltage equipment, and the substation. Specifically, as the lower-level power plant, the dual-generator operation requires state-of-the-art automatic control and a digital water level control system with feed-forward control. This level regulation system has now been exactly adjusted to the actual quantity of water in the turbines. The water is allocated to the machines precisely according to the respective efficiency curves to ensure that

The turbine water from the Ozola River is channelled directly from the upper power plant (built in 1928) via a gravity sewer to the surge chamber.

the power plant is always operated to optimum efficiency. The en-co electrical engineering specialists have now also implemented self-contained black-start capability of the power plant, for example after a power failure.

REMAINING WORK At the end of the thaw in June of last year, the two old machines were disconnected from the grid and the retrofit project got under way.

Electromechanical Equipment for Small Hydropower Stations

More Sustainable Energy from Hydroelectric Generation

GEPPERT GMBH A-6060 Hall in Tirol

www.geppert.at

since

1896

photo credits: zek

make the turbines even more resistant to environmental influences. The larger of the two generators in the Ligonchio power plant has therefore become the first reference turbine in this performance category and has continued to prove itself for months.

The entire task took less than half a year and the new hydropower sets were commissioned in December. However, the entire project has not yet been completed. In the near future, conversion work is planned in the intake building, the surge chamber and raking device, and the supply pipe for the small machine will of course also be replaced. A lot of the electro technical and control detail is also soon to be implemented by enco. The new equipment has an additional total installed capacity of around 500 kW today compared to the old setup. That is remarkable, but still does not allow any precise conclusions to be drawn regarding the increase in the plants' standard capacity. The Ligonchio power plant currently generates around 5 million kWh in a standard year. Thanks to the higher efficiency of the new hydropwer set, the higher volume of water and more effective control system, it should certainly be possible to raise this by a couple of per cent. However, it is not possible to determine by exactly how much until operation starts. The operator is more concerned that the renovation has been successful, that the plant now meets all the current demands placed on hydropower plants, and that operational reliability has been ensured thanks to the high quality of the machines for many years to come. Finally, the high quality of the machines made in Austria is ensuring that red-white-red hydropower technology is making a name for itself in the mountains of the Apennines too. April 2013

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new vertical pressure tunnel (inside mountain) old penstock (above ground)

photo: Eisackwerk Mühlbach

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underground cavern power station

old power house access tunnel and water outlet

Diagram of the hydropower facilities in the South Tyrolean market town of Mühlbach

PRIVATE PIONEER PROJECT OPTIMISES POWER GENERATION FOR SOUTH TYROLEAN COMMUNITIES

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uilt in the 1940s and 1950s, the double hydropower plant in the South Tyrolean Pustertal region was a local landmark of sorts, with its two penstocks running straight across the town of Mühlbach, much to the displeasure of the local population. For one thing, the humming of the turbines and generators in the nearby power house at the Mühlbach reservoir were clearly audible far and wide during the night. Also, the steely twin pipe, through which the waters were constantly gushing with an inside pressure of more than 60 bar, represented a considerable danger.

PRIVATE PROJECT APPLICANTS WIN OUT WITH INNOVATIVE CONCEPT It was precisely these two rather unpleasant characteristics of the existing facilities that the two private project applicants decided to address with their new implementation concept. Deviating from the project designs of the

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photo: Eisackwerk Mühlbach

In 2009 the permit for the almost century-old hydropower plant in the market town of Mühlbach was up for re-application. But it was not the region’s big players of the energy supply industry that won the project at the head of the Pustertal, but two ambitious businessmen from Bozen. Their well-conceived, sustainable concept won the day – and the permit. Dr Karl Pichler and Hellmuth Frasnelli – who each hold a 37.25% stake in plant operator Eisackwerk Mühlbach GmbH – showed great determination and patience during the ensuing legal negotiations. In the end, their perseverance was rewarded with the successful startup of their innovative hydropower station in the autumn of 2012.

The route of the old penstock led straight through the town.

competing energy suppliers, which called for an overground penstock to the old power station, the Eisackwerk Mühlbach GmbH proposed to install the motive water pipework under ground through a 430 m tunnel leading to a new cavern power plant inside the mountain. “One mustn’t forget that the existing penstock pipes had been subjected to pressures of up to 62 bar for 60 and 70 years, respectively. Who knows what might have happened if the pipes had been damaged by falling rocks or something like that,” says Hellmuth Frasnelli, commenting on the disaster hazard of open-air penstocks in the middle of an urban area. In intensive collaboration with the contracted planning offices of Studio G of Bruneck, project manager Dr Karl Pichler managed to develop the idea of using underground pipes into a workable project plan, which eventually won the full approval of the responsible officials during the contract awarding process.


photo: Eisackwerk Mühlbach

photo: Eisackwerk Mühlbach

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The intake at the Valser Bach stream was also fitted with the patented Coanda trash rack system by Wild Metal.

UPHILL STRUGGLE FOR A PERMIT But despite the decision, for Eisackwerk Mühlbach GmbH the project was far from being a done deal, as local authorities and political representatives kept criticizing the “radically innovative” character of the new concept. Until they finally were granted the required permission in November 2009, the two managing directors had to fight for approval all the way, including litigation in six cases against public offices and the provincial government. From the time when they submitted their planning documentation in 2005, the uphill struggle for the Pustertal power plant project went on for almost four years until all court cases were finally settled and the two innovators were granted permission for water power utilisation until 2040. With this hurdle cleared, they could concentrate fully on their ambitious power plant project for the Mühlbach region. NEW INTAKE WITH PATENTED COANDA SYSTEM The project plans called for the complete renewal of the existing (and still used) components of the motive water pipework in the upper section of the facilities. Renovation

The entrance portal of the 850 m access tunnel to the power plant cavern

work began at the main intakes at the weir gates in Pfunders and Vals, which were completely renewed and fitted by Wild Metal of Ratschings with a new Grizzly trash rack. This patented intake system, which combines a Coanda screen with integrated protective rack, was installed in place of the original classic Tyrolean weirs. Gufler Metal of Moos in Passeier supplied and installed the other hydro steel structures for the project, including, among others, 26 barrier sluice gates with frame heights of up to 8 metres. The granted permit also authorised an increase in the design flow rate for the two new machine units in the central control cavern. This allowed the project operators to draw water at the Pfunderer Bach intake at 2.3 m3/sec (previously 2.0 m3/sec) for their electricity generating purposes. At the Valser Bach intake, the flow rate was increased to 1.9 m3/sec from previously 1.5 m3/sec. At the same time, however, the residual water flow at both streams had to be increased as well in order to preserve the ecologic qualities of the outflow reaches. Also, the weir facilities at the Valser Bach had to be fitted with a fish pass, which was implemented by the Studio G planners of Bruneck in the form of a pool

pass with cross-wall notches and submerged orifices. RAISE-BORING METHOD ENSURES PRECISION AND MANY BENEFITS The main intakes are situated at different elevations: the Pfunders at 1,350 m above sea level, and Vals at 1,250 m.a.s.l. From there, the existing headrace tunnels lead to their respective pressure basins with surge tanks, which were completely refurbished as part of the overall renovation work. From these points onwards, the two pipes now run in parallel, not over-ground downhill towards Mühlbach as previously, but through a vertical pressure shaft – which was excavated using the so-called raise boring method – towards the power house cavern inside the mountain. “After 430 metres, the deviation of our pilot bore was only about 3 cm. For a 25 cm core bit, that is quite impressive”, explains Dr Karl Pichler in commenting the high-precision work of the tunnel excavation team. With the initial bore for the 2 penstocks and the breakthrough into the excavated cavern complete, new core bits with diameters of 1,5 m and 1.8 m, respectively, were fitted to the

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flange pipe and raised while in rotation, thus creating the required shaft. With this drilling method, the excavated material simply drops to the ground, where it can be collected and removed quite easily. This allowed for a steady progress of around 20 m a day. Raise boring has other advantages as well: the machinery can be operated safely outside the mountain, and the method allows for higher excavation speeds at low operating effort. NEW PENSTOCK DIMENSIONS Once the excavation work for the pressure shafts was finished, the engineers went on to insert and install the new steel penstock pipes. The 12 m pipe sections were welded together near the shaft entrance and lowered carefully into the mountainous depth. When the last pipe sections were installed, the total weight carried by the hydraulic lift amounted to more than 200 tons. “Once the pipework was in place the two shafts were bricked up,

so everything should be maintenance-free for the next hundred years, and that’s that!”, says Hellmuth Frasnelli emphatically, confirming the longevity of the steel penstock pipes. During the planning stage for the new penstock runs, the extension of the previous pipe diameters was a key issue, as it was essential for boosting the capacity of the new plant. “The old penstock for the machinery in Vals was a combination of DN600 and DN700 pipes. For the new pipework we used DN1100 pipes throughout. This way, we were able to reduce the hydraulic loss significantly, which means a higher net head and higher energy output,” explains DI (graduate engineer) Thomas Fiechter, project manager at hydropower specialist Troyer. VISIONARY SOLUTION WITH STRUCTURALLY IDENTICAL TURBINES BY TROYER Wherever the name Troyer is mentioned, one usually does not have to look far for the tur-

The two private project operators Hellmuth Frasnelli and Dr Karl Pichler, and construction supervisor Walter Unteregelsbacher of Oberloser (left to right)

photo: Eisackwerk Mühlbach

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Following the breakthrough into the power cavern, the core bit for raise boring is fitted.

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Next, the 12 m steel pressure pipes are carefully lowered into the tunnel.

photo: Eisackwerk Mühlbach

photo: Eisackwerk Mühlbach

The drive rig used for the vertical bores delivers 300 kilowatts of pure excavating power.

photo: Eisackwerk Mühlbach

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bines by the renowned family-owned manufacturer of the South Tyrolean town of Sterzing. In the power house of the new Mühlbach hydropower facilities, two nearly identical four-jet Pelton turbines have replaced the original machinery, which remains in the old power house 700 m away. Describing the new turbines as “structurally identical” may sound slightly confusing at first, considering that they are not only designed for different design flow rates, but also work with different water heads: 622 m in the case of the Pfunders machine, and 487 m for the one in the Valsertal. “But to keep things easy for the customer in terms of replacement parts, the machine in Pfunders is operated at 1,000 revolutions per minute, and its ‘almost identical’ twin in Vals at 750 rpm,” reports Troyer’s project manager Thomas Fiechter. NEW HYDROPOWER PLANT GENERATES 20% MORE OUTPUT Both of the high-grade, air-cooled synchronous generators were provided by Lloyd Dynamowerke of Bremen (Germany); they can achieve output efficiency levels of up to 98%. The operating heat of the generators is dissipated through a closed cooling system into the used motive water, which is carried into the Mühlbach reservoir by way of two concrete pipes installed at the bottom of the 850 m cavern access tunnel. As a result of the comprehensive modernisation, the output of the new facility is more than 20% higher, thanks to the increased design flow rate, the higher output efficiency, optimised partialload behaviour of the new 4-jet turbines, and the improved, widened pipe hydraulics. In effect, these improvements translate into an increase in installed capacity from the old facility’s 16 MW to 20.7 MW.


Installers of Troyer are busy performing welding work on the water ring duct of the Pelton turbine in Pfunders.

photo: Eisackwerk Mühlbach

photo: Eisackwerk Mühlbach

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Inside view of the four-jet vertical Pelton turbine, whose rotator measures 1,100 mm in diameter.

The two penstocks finally lead into the underground power station cavern.

SOUTH TYROLEAN VALUE CHAIN When the second machine was connected to the grid on November 16, 2012, the two project organisers could finally breathe a huge sigh of relief, take a step back and look at their achievement with a certain sense of pride. “We made a conscious decision to award all project contracts to South Tyrolean firms,” says Hellmuth Frasnelli, thus confirming the essentially regional character of the entire project. Of the 26 million euros that he and his business partner Karl Pichler invested into the project, they provided 20% themselves, the remaining 80% were contributed by Unit Credit Leasing, with an expected amortisation period of 18 years. But there is another thing the two private operators want the locals to profit from: Eisackwerk GmbH intends to grant 50% discounts, for up to 1,800 kWh per year, to all

households in the Mühlbach community that have 3.3 kW mains connections. In case this is not possible for legal reasons, the operators intend to donate an equivalent amount to charitable causes in the region. This generous offer is the final highlight that underscores this ambitious and thoroughly successful model project in the South Tyrolean energy supply industry.

Technical data: w w w w w w w w

Total flow rate: 4.2 m3/s Gross head: 487 m ; 622 m Turbines: 2 x vertical Pelton Manufacturer: Troyer Generator: 2 x Synchronous Manufacturer: Lloyd Dynamowerke Installed capacity: 20.7 MW Annual production: 100 GWh

photo: zek

photo: Eisackwerk Mühlbach

RECORD-LENTH UNDERGROUND HIGHVOLTAGE CABLE To be able to feed the expected annual energy output of 100 million kWh into the grid, Troyer – which also supplied the entire medium-voltage and protection technology – transported the transformer from the old power house at the Mühlbach reservoir to its new destination at the entrance to the cavern access tunnel. The transformer station located there, together with another, smaller transformer, now convert the generators’ 15,000 V output power to 132,000 V before it is carried via a 800 m underground high-voltage cable to the transmission line at the old power house. Troyer kept the old power station operational until 2012, when it was finally time to switch over to the machinery at the new Mühlbach cavern power plant.

The two LDW synchronous generators in the underground cavern after startup of the Mühlbach power station

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Gufler Metall KG, based in the South Tyrolean Moos in Passeier, Italy, has been a big player in the field of hydraulic steel engineering for over 20 years. Originally a blacksmith and locksmith business, it was founded by Gothard Gufler in 1991 and over the years developed into a hydropower specialist focusing on metal construction, hydraulic steel engineering and penstock welding. Gufler's proud references include almost all new hydropower plants built in South Tyrol in the last few years. Therefore it comes as no surprise that Gufler Metall KG was commissioned to provide the special hydraulic steel engineering and welding works at the new Mühlbach power plant.

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n the course of the renovation of various water catchments of the Mühlbach power plant in the South Tyrolean Puster Valley, Gufler Metall delivered and installed numerous hydraulic steel components, including a total of 26 gate valves with a frame height of up to 8 meters. These valves were installed in the water catchments on the Pfundererbach Creek, Valserbach Creek and Eiterbach Creek, as well as in the surge chambers of Pfunders and Vals.

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Foto: Gufler Metall

GUFLER METALL KG FACES SPECIAL TASKS AT THE MÜHLBACH POWER PLANT

Two technicians of Gufler Metall are welding together a penstock on the challenging grounds of the Mühlbach power plant.

Furthermore Gufler Metall KG was responsible for supplying and installing the penstock protection valves of a dimension of DN1200 and a pressure rating of PN10, as well as the bellmouth and the supply and return air ventilation ducts of the two surge chambers.

SPECIALISED IN WELDING OF PENSTOCKS The welding specialists of South Tyrolean hydraulic steel engineering company Gufler were even assigned the welding of the new

penstocks from the two surge chambers to the passage into the vertical shaft. These tasks were performed partly on steep and challenging grounds. The highly qualified personnel employed by Alfred and Gothard Gufler are constantly kept up to date regarding the newest technology and operation processes. This guarantees Gufler Metall KG's high-quality products and the company's consistent success.


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GRIZZLY MODULE SYSTEM: TREND-SETTING WATER CATCHMENT TECHNOLOGY

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dapting the water catchment to stateof-the-art technology was an important stage of the modification project of the M端hlbach power plant. This is why the operators decided on a new and highly efficient rack cleaner system, which guarantees the highest screen capacity and the lowest maintenance requirements: the Grizzly by Wild Metal. Its patented catchment concept, which is constantly revisited by the manufacturer based in Ratschings, South Tyrol, combines a robust, hot dip galvanized protective screen with a Coanda screen placed underneath it. To significantly increase the functionality of the catchment on the Valser Bach Creek, its

The new Grizzly rake at the water intake Valser Bach

existing structures were adapted by installing 14.5 elements of the Grizzly rake modules. The water catchment on the Pfundererbach Creek is a clearly larger version with 18 integrated modules of the Grizzly 2300. With a breadth of 20 meters it is the largest water catchment with a Coanda system in the Alpine region. It is designed for a guaranteed capacity of 3,000 liters per second. The extrastrong protective rack was designed to divert even a heavy bed load of a few tons safely over the catchment during high water periods. MINIMIZING CONSTRUCTION COSTS WITH THE GRIZZLY SYSTEM The patented Grizzly rack module is a truly innovative development by Wild Metal. The basic technical improvements in comparison to a Tyrolean weir are the shorter gap spacing

photo: Wild Metall

The new operator of the M端hlbach hydropower plant, Eisackwerk M端hlbach GmbH, hired Wild Metal, a company based in South Tyrol, Italy, to supply and install the entire hydraulic steel engineering components in the course of the modification works of the plant. Grizzly rake modules for water intakes turned out to be the ideal solution for an efficient and low-maintenance discharge of process water. This system, patented by Wild Metal, combines an integrated protective rack with a Coanda screen and skims off the smallest sediments and debris. The water catchment on the Pfundererbach Creek is equipped with a Grizzly 2300, which is the largest Grizzly module ever used in power plants.

of the Coanda screen and the integrated protective rack. The gap spacing of the Coanda screens used at the catchment of the M端hlbach power plant is 0.5 mm. This means that only particles with a grain diameter of less than 0.3 mm can enter the process water system. Consequently the grit chamber is smaller in dimension and in that way saves construction costs. Pine needles, leaves, twigs and other debris is washed over the catchment and floats off. The design of the module offers an extraordinarily simple and quick installation. Another characteristic of the Grizzly rack is its low height. Together with the newest development of coarse rack bars expanding towards the bottom, it represents the most maintenance-friendly rack cleaner system for water catchments currently available in the hydropower market.

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photo credits: Andritz Hydro

The Budweis Sokolsky power plant lies in the center of Budweis on the Sokolsky island, where the Vltava and Malse River join. It has been one of the five highest-performing power plants in South Bohemia since the 1930s.

OUTPUT DOUBLED AT LONGSERVING BUDWEIS POWER PLANT The long-operating hydropower plant on the Sokolsky peninsula in Budweis, Czech Republic, was renovated, modernized and provided with state-of-the-art hydropower technology in a comprehensive project last year. In December 2012 the three almost 80-year-old turbines were replaced with modern vertical Kaplan turbines from Andritz Hydro's Standard Compact program. These turbines are now driving high-performance synchronous generators manufactured by TES Vsetin. With the successful renovation of the plant the total output has been doubled to 1,320 kW. power plant in South Bohemia is its weir plant. Exceptional features of the plant are the two approximately 28 meters long cylinders with a diameter of about three meters, designed to close the two-span weir. The log flume was constructed orographically on the left side, while the powerhouse was positioned on the right.

The new high-performance and robust synchronous generators

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photo credits: Andritz Hydro

Three vertical, double regulated Kaplan turbines were installed.

installed, but these machine units were replaced after only a few years, in 1936. One of the Francis turbines was replaced with a Kaplan turbine of a higher performance, manufactured by Storek. The total output of the three turbines (210 kW, 250 kW and 300 kW) at that stage was 760 kW. A significant element of this long-established photo credits: Andritz Hydro

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n the early 1930s the provincial government of Bohemia built a hydropower plant on the well-known Sokolsky island, where the Malse and the Vltava River join. The plant was put into operation in 1933 to produce electricity for the city of Budweis and its trams. In the beginning three Francis turbines had been


The old machine unit

OLD PARTS CIRCULATING A HUGE OIL FLOW German Schmatz GmbH acquired the power plant in the 1990s. “At that point, the power plant was out-dated, as we had expected it to be. The machine units from the 1930s were, of course, operating with an enormous oil circulation. However, there was an automatic system installed, which operated the old machine ensemble more or less automatically,” says Sigi Dietl, managing director of Bodenmais-based Schmatz GmbH. Aqua Energie, the official operator of the plant, did not hesitate to modernize it. The old centrifugal governors as well as other controlling devices were replaced with hydraulically regulated control systems 15 years ago. A modern automatization system made it possible to operate the power plant with the newest technology available. ISATS delivered the software and hardware for this system. MORE HEAD THROUGH BED DEGRADATION Originally the turbines were designed for a water amount of 10.2 m³/s and 11.5 m³/s, respectively, and a gross head of 3.4 meters. This all changed within the last decade when the Czech government launched a new project. The aim of the project was to improve flood control and shipping. A shipping service from Prague to Budweis was planned. The head was increased to 4.9 meters by lowering the bed in the tailwater. Adjusting the power plant to the new conditions presented a complex challenge. “Together with river management company POVODI VLTAVY and the University of Prague, Department of Hydraulic Structures, we had worked intensively on the ideal adaptation of the power plant since 2008. At the Department of Hydraulic Structures the team of Professor Fosumpaur constructed a model plant and proved that our reconstruction plans were not interfering with the state's project for improvement of the shipping sector. On the contrary, we showed that ships were better able to make turns through the new design of the outlet. An expert opinion with a trial run in the model was compiled in

photo credits: Andritz Hydro

photo credits: Andritz Hydro

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The old turbines were removed in the late fall of 2011.

2009. The technical know-how of Professor Fosumpaur and his team was a huge support for us,” says Sigi Dietl. He adds: “Meanwhile smaller passenger liners steer close to our power plant where they can turn in a special turning basin.”

AMBITIOUS TIME SCHEDULE Thanks to the excellent cooperation with POVODI VLTAVY and the University of Prague the reconstruction project was finally approved. On October 5, 2010 the authorities gave the project the green light. After the following public invitation to tender the contract was awarded to construction company VHS Vodospodarske stavby s.r.o. Andritz Hydro won the contract for the electromechanical equipment of the plant. The contract comprised three vertical, double regulated Kaplan turbines with a diameter of the runner of 1,450 mm. Furthermore it included the appropriate oil hydraulic power unit, installation surveillance, commissioning and training. The reconstruction works started in August and it soon became clear to all participants that the timetable was scheduled rather ambitiously and optimistically. For the installation of the turbines, for instance, the draft tubes had to be adjusted and reset in concrete. The

Installation of the new guide vane apparatus in January this year.

existing concrete volute casings, however, could be used for the new turbines.

CRUCIAL POINT: BUILDING STATICS “There were two main challenges with this project: first we had to deal with the tight schedule along with the difficulties of conducting the installation works at temperatures below zero and, second, we had to deal with the building statics. Assigned structural designer Mr. Krug from CDM Bingen did an excellent job and supported the construction company very well. Mr. Reisser of Andritz Hydro and I planned the machine units together, while the construction management was handled by the Czech company manager, Mr. Prasnicka, and me. ISATS was again responsible for the entire control technology and the electrical engineering works,” says Sigi Dietl. The installation team and the supplier of the electrical engineering had to face Arctic temperatures last winter, which were constantly between minus 10 and minus 20 degrees. The works could finally be completed in February this year. As the operator put it: “We had extreme frost and two meters of ice in the river this February. Still we managed to put the machine units into operation.”

Technical data: w Flow Rate: 10 m³/s each (3x)

w Gross Head: 4.9 m

w Turbines: Vertical Kaplan Turbines

w Quantity: 3

w Turbine Capacity: 440 kW each

w Manufacturer: Andritz Hydro

w Runner Diameter: 1,450 mm

w Blade Quantity: 4

w Generator: Synchronous Generator

w Nominal Apparent Output: 430 kVA

w Nominal Rotation Speed: 230.77 rpm

w Frequency: 50 Hz

w Manufacturer: TES

w Nominal Voltage: 400 V

w Average Energy Capacity: Approx. 7 GWh

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Successful cooperation: Operator Sigi Dietl and Martin Reisser of Andritz Hydro.

EFFICIENT ENSEMBLE OF MACHINES Thanks to the lowering of the tailwater level and the subsequent increase of the head the operator was able to install machine units of considerably higher performance and efficiency. The three double regulated Kaplan turbines manufactured by Andritz Hydro are designed for an output of 440 kW each. The total installed machine capacity is now 1,320 kW, which is almost twice as much as the output of the original machine unit. In addition to the new and efficient highperformance turbines, the operator is now also using high-quality synchronous generators by TES Vsetin. The machine units of TES Vsetin stand for generous design, robust constructional components by renowned manufacturers and great know-how. The brushless synchronous generators for hydropower use are the Czech company's flagship products. Today the Vsetin-based company produces generators of an output of 30 to up to 15,000 kVA.

View of the power plant from the upstream side: After the modernization the new Budweis Sokolsky power plant will produce approx. 7 m kWh in an average year.

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photo credits: Andritz Hydro

Acceptance of the turbines at Andritz Hydro.

The three generators operating in the Budweis Sokolsky power plant have a nominal apparent output of 430 kVA. They are driven at a nominal rotation speed of 230.77 rpm.

THE TECHNICAL JEWEL ON THE VLTAVA RIVER STEPS INTO A NEW HYDRO POWER ERA Although the capacity of the turbines has been reduced marginally to 10 m³/s, the increase in output and production is striking. Sigi Dietl and his company manager expect a production of approximately 7 m kWh in an average year. This makes the power plant one of the five biggest hydropower plants in South Bohemia – just like at its commissioning 80 years ago. It is not under monument protection but it is regarded as a technical jewel in Budweis and beyond. The power plant has made a momentous transition to a new hydropower era with its new equipment.

photo credits: Andritz Hydro

photo credits: Andritz Hydro

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photo credit: Kössler

On November 4, 2012, Albanian Prime Minister Sali Berisha attended the inauguration ceremony of the new Lapaj power plant on the Bushtrica River.

HYDROPOWER TECHNOLOGY FROM LOWER AUSTRIA FOR NEW PRESTIGIOUS POWER PLANT IN ALBANIA In November last year Albania's highest government officials and other top politicians got together in the periphery of the small town of Kukes in the northeast of Albania to inaugurate the new Lapaj hydropower plant. In 2008 works started on the plant, which was realized as the first part of a comprehensive cascade project on the Bushtrica River. Hydropower as an energy source is of the greatest significance in Albania. A plant that provides electricity for more than 22,000 Albanian families is considered a national priority. For this reason a provider for the installed hydropower technology was carefully selected. Lower Austrian hydropower specialist Kössler was awarded the contract for the electromechanical equipment of the power plant, the best advertisement for Austria's hydropower technology.

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simple push of a button highlighted the outstanding opening ceremony of the new Lapaj power plant on November 4, 2012. None other than Albanian Prime Minister Sali Berisha launched the two machine units and put the prestigious plant into operation. Guests included Minister of Economy and Energy Edmond Haxhinasto, Minister of Interior Affairs Flamur Noka, Italian Ambassador Massimo Gaiani as well as numerous high-profile politicians, economists and representatives of society. The glamor of the occasion reflected in particular the new power plant's importance for the regional electricity supply and the general

use of hydropower in Albania. Prime Minister Sali Berisha called the project “an important step in the constant transformation of Albania into a regional power for renewable energy.” One can guess the economic significance of this project for the country by looking at the number of 2,500 people being directly involved in the realization of the plant. The construction of the plant took about 4 years to complete. WATER FROM GREAT HEIGHTS The project was based on a feasibility study dating from 2007, which was conducted by diploma engineer Islam Zhupa. The extensive

research focused on the course of the Bushtrica River in the valley with the same name. The river runs from the east to the west in a V-shaped course through the province of Kukes in the northeast of Albania, which is still extremely remote. A gauging station in operation since 1971 provided the planners with comprehensive hydrological data on the flow characteristics of the river. The source of the river lies at more than 2,000 meters above sea level where the two creeks Reka and Lushi originate and unite along their courses. With the confluence of even more creeks and especially of the Caja River, the Bushtrica becomes a characteristic April 2013

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of the landscape with a total catchment area of 132 km2. One important issue in the planning of the Lapaj power plant and the other intended cascade power plants was learning about the characteristics of the flow and the bed load during heavy rainfall. Especially the water of the Caja River is known to carry a great amount of clay and sand and to generally have a large bed load. The Bushtrica has the reputation of adapting the features of a torrent during heavy rain and was feared for its floods. These issues played a central role in planning, which, however, was completed rather fast due to the feasibility study and the green lights given by Albanian politicians. THE FIRST LINK IN A CHAIN OF TEN PLANTS The plans comprised a chain of ten power plants set to be situated along the Bushtrica River. The first one to be realized was the Lapaj power plant as the central plant of this chain. Four plants are currently being planned upstream and five downstream. Lapaj is the core plant of the power plant cascade due to its high output of 2×6.81 MW. It is also the junction of the grid connection and the control center for the cascade. The project is run by Gjo-Spa Power, a majority stake in which is owned by Italy's ETEA Group, a very active enterprise in the fields of renewable energy. The group is also the majority owner of the other operating company involved, Hidrobushtrica, which will realize and operate all other cascade plants. The plant concept for the Lapaj power plant includes two water catchments, the second catchment and the connected open channel will be completed within the next few months. Currently the process water – with a maximum of 6 m³/s - is fed into a catchment designed as a Tyrolean weir. From there the water runs through a sedimentation basin into a 2.75 km long concrete channel before it reaches a cushio-

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ning basin with a capacity of 2,000 m3. Then the water is led into the two turbines via a double-legged 570 meters long steel penstock DN 1300. Along the way the process water flows down a slope of 258 meters. HYDROPOWER TECHNOLOGY FROM LOWER AUSTRIA The core of the plant are two state-of-the-art machine units consisting of two Pelton turbines with 6 injectors, each of them driving a synchronous generator with a nominal rotation speed of 600 rpm. The turbines were produced by Austrian hydropower specialist Kössler, the company that is also responsible for the two shut-off valves, the turbine governors, the closed-cycle cooling system of the generator bearings and the pipe burst valves. Further features of the plant constructed by photo credit: Kössler

Two high-performance machine units provide an average annual output of about 50 GWh. The high-quality turbine technology comes from Lower Austrian hydropower specialist Kössler, also responsible for the core piece of the plant, two Pelton turbines with 6 injectors.

photo credit: Kössler

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The Pelton runners for the Lapaj power plant have been designed and constructed according to the highest standards at Kössler.


the Lower Austrian provider of hydropower technology are the electrical engineering, safety components as well as the entire SCADA system. This has not been Kössler's first order coming from the southeastern country with a huge potential for hydropower. Kössler had delivered Francis and Pelton turbines to Albania before and had received only positive feedback for its services. This might have been the reason why the Lower Austrian company was awarded the contract to equip the prestigious power plant Lapaj with the electromechanical units.

photo credit: Kössler

SNOWED IN AND NO ELECTRICITY The period from order acceptance until delivery and launch of the plant was an eventful journey. Again and again adverse weather and difficult terrain conditions led to delays in the construction schedule. The contract was signed in June 2010, however in accordance with the owner the construction works could not start until November 2011. Works then started under extremely harsh conditions: “It was a very hard winter. The supply of the construction site with consumables, diesel for emergency power systems and for heating was slowed down. At one point the electricity supply collapsed and the construction workers were snowed in, which forced the project to a halt. On our part the works were completed in May last year,” says Stefan Kunst, offer project manager. He adds: “However, the cooperation with the owner was excellent. Even before the machine unit was constructed they had built a hotel nearby so all people involved in the project could reside close to the power plant site.” After the completion of all final works the machine unit was put into operation in early July 2012. The commissioning of the power plant took place in mid-July. Ever since the machine units have been working reliably and

Operator Gjo-Spa Power invested about 15 million euros in the realization of the new Lapaj power plant.

photo credit: Kössler

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The architecture of the new power plant also reflects its importance. The plant is responsible for the electricity supply of the region and represents the central junction for the regulation of all cascade power plants.

very efficiently and were stopped only once for the occasion of the official inauguration, just to be put into operation again soon after by Prime Minister Sali Berisha. IMPORTANT ECONOMIC IMPULSE The operator decided on a turbine with 6 injectors due to the flow characteristics of the river. The process water at disposal in the Bushtrica can rise and fall suddenly. Especially in the summer months July, August and September the water level is at its lowest. In this case it is important that the turbines can operate with a decent degree of efficiency at a low pressurization. The operator can now rely on Kössler Pelton turbines even in this situation. Both installed turbines are designed for an output of 6.81 MW. In total they will provide an average of about 50 GWh of clean electricity for the regional district of Kukes annu-

ally. The supply is sufficient for 22,000 Albanian families. As there are still many problems with infrastructure in the northeast of Albania a hydropower project of this size is given the highest priority. For this reason Prime Minister Sali Berisha in his opening speech strongly emphasized the positive effect the plant has on the region and its economy and underlined that hydropower is the most important source of energy of his country. For turbine specialist Kössler the project on the Balkan Peninsula produced equally positive results. With this international project Kössler proved that the company stands for machines of the highest quality, reliability and competence in construction and commissioning. The Lower Austrian provider of hydropower technology not only became a desired cooperator in the further development of hydropower in Albania but has already been offered follow-up orders.

Technical Data: w River: Bushtrica (AL)

w Drainage Area: 132 km2

w Net Head: 258 m

w Flow Rate: 6 m3/s

w Turbines: Pelton Turbines 6 nozzled

w Pieces: 2 Pieces

w Output: 2×6.81 MW

w Rotational Speed: 600 rpm

w Generator: Synchronous Generator

w Nominal Apparent Output: 7,978 kVA

w Open Channel: l=2,750 m

w Penstock Material: Steel

w Penstock: l=570 m

w Penstock DN1300

w Average Energy Capacity: approx. 50 GWh

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It's not only hydroelectric power stations "Made in Austria" that are in high demand. Control and automation systems from the Alpine republic also enjoy a strong reputation in the sector. Schubert Elektroanlagen from OberGrafendorf in Lower Austria, which has been providing electrical equipment for 40 years, is a perfect example of this. One of the newest and yet most prestigious reference projects was recently completed in Albania: Schubert managed the entire control and automationsystem for the important Lapaj cascade hydroelectric power station, fitting it with an efficient "nervous system" that meets the state of the art in hydroelectric technology.

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photo credits: Schubert

ardly any other hydroelectric power station in the Balkans has been in the international headlines in the last few years as much as the Lapaj power station. It has become the symbol for the Albanians’ efforts to press ahead with their country's expansion of its own hydropower potential. The conditions could hardly be more favourable. With mountains up to 2,800 meters high and the best precipitation patterns due to its damming position, the south east European country is one of the most promising growth markets in Europe in terms of hydropower.

The Schubert Elektroanlagen team also installed the enclosures of the 20-kV switchgear.

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photo credits: KĂśssler

RED-WHITE-RED "NERVOUS SYSTEM" FOR EXEMPLARY ALBANIAN POWER PLANT

1The Lapaj power plant is the hub of the entire cascade system. It not only acts as the monitoring and control centre, it is also the grid feed-in point. All of the electro technical equipment was provided by Schubert Elektroanlagen.

The potential for expansion is estimated to be around 12 TWh and and Albania is thought to have currently developed only around one third of its economically and ecologically usable potential. If you consider that the country continues to import around 50 percent of its electricity from abroad, it is easy to see why the Albanian government under Premier Sali Berisha places such importance on the expansion of hydropower, and thus attracting wealthy investors to the country. Particular attention has been paid the new power station at Lapaj. It is actually a key pro-

ject. Firstly, it is highly significant as an infrastructure project, since it generates electricity for around 22,000 Albanian families in a region where economic development still lags far behind Central European standards. Secondly, it is the technical centrepiece of a whole chain of cascade hydropower plants to be constructed along the Bushtrica River. A TRIED-AND-TESTED CONSORTIUM Not least because of the power station's great significance, the operators, Gjo-Spa Power, did not want to make any compromises when it came to the plant's technical equipment. High demands were placed on the availability, durability and efficiency of the hydropower technology employed. Only the very best quality was considered. Quality which hydropower specialists such as Kossler or Schubert Elektroanlagen are known to guarantee. As a consortium under the leadership of the Lower Austrian turbine manufacturer, the two companies were awarded the contract for the power station's electrical equipment. "For us it meant that we would be providing all the electrical equipment, from various types of measurement sensors to the 24 kV grid feedin, over the period of approximately one year. We received the order in June 2010 the contract, and in June 2012 we completed the project with its commissioning," explains the Power Station Division Manager at Schubert, Ing. Christian Schwarzenbohler.


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PREVENTING A "BOTTLE NECK" What the made the task particularly challenging for the experienced electrical engineering specialists from Ober-Grafendorf was the fact that the power station is to be the hub of the planned chain of power stations. As Schwarzenbohler explains: "The Lapaj power station will be the feed-in point for all the planned power stations. For us, the conceptual challenge was to construct this plant to be suitably robust and reliable. We had to create a situation whereby it would not create a "bottleneck" in terms of the energy supply when it is later connected to the other upstream and downstream plants, and ensure that availability and reliability will remain high. A further important aspect was the SCADAsystem. It had to be programmed and designed so that the cascade can also be controlled, monitored and managed centrally from the Lapaj power plant." A proven turbine control system is used, which is precisely aligned to the optimum points of the turbines’ efficiency curves and also controls the crossover points for the interaction between the two hydroelectric sets. Christian Schwarzenbohler's team have once again demonstrated their competence on this project. They are now able to draw on the enormous amount of experience gleaned from the roughly 400 hydropower projects performed by Schubert Elektroanlagen around the globe over the last 40 years.

photo credits: Schubert

FLEXIBILITY BRINGS ADVANTAGES The equipment installed in the prominent Lapaj power plant by no means represents Schubert Elektroanlagen's dĂŠbut in the south east European country. It is actually the fourth plant it has worked on in Albania, and two more are currently under construction, due to be put into operation later this year.

As is the case with Schubert, all of the comprehensive data and operating conditions were displayed in a visualisation system, which is highly appreciated thanks to its clarity and ease of use.

There are several factors behind the electrical engineering and control technology success of the company from Lower Austria in the hydroelectric power station sector. One of them is certainly the flexibility of a company that has advantages in terms of its size when it comes to its internal organisation and pricing structure. Then there is the famous high quality. This stems from the fact that the Schubert electrical engineering solutions are developed entirely in house. "This certainly works in our favour. We manufacture our switchgear here in house, all the way through from the planning stage to execution. And we intend to continue building on this advantage. In the future, using a 3D CAD design system will enable us to plan and execute the switchgear production and electrical installations even faster and more accurately. This will take us yet another step ahead of the competition, and another step closer to our

customers," says Christian Schwarzenbohler. With the order for the equipment of the new Lapaj power station, Schubert was able to make full use of all the synergy effects of a broad-based energy technology company. "Because the scope of delivery included all the electrical equipment, we were able to provide everything from a single source. This is great, but on the other hand, it requires the highest level of teamwork from all the departments in our company. To then be able to come up with an overall concept for a major customer, from the smallest sensor to the grid feed-in, also requires reliable project management. And this is else something we place great value on," explains the division manager. In any case, the Lapaj power plant project represents a satisfying conclusion for him. An ambitious project which once again demonstrates the high level of competence of the Austrian hydropower company.

For further informations: Schubert Elektroanlagen GmbH Industriestr. 3 3200 Ober-Grafendorf AUSTRIA Ing. Christian Schwarzenbohler Head of Power Plant Technology c.schwarzenbohler@elektroanlagen.at Mobil: +43(0)676-832 53 164 Telefon: +43(0)2747-2535-164 www.elektroanlagen.at

The data of the surrounding cascade power plants are collected in the Lapaj power plant.

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photo: Axpo

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Dammed-up Lake Limmern with its 92 million cubic metres of storage capacity forms a central part of the Linth-Limmern power plant complex in the eastern Swiss canton of Glarus.

CONSTRUCTION SITE OF THE CENTURY AT PUMPED-STORAGE PROJECT LINTHAL 2015 The Linth-Limmern power stations were erected in the years between 1957 and 1968. The large-scale power plant, which comprises the Linthal facilities and the two underground power stations of Muttsee and Tierfehd, was designed for an overall capacity of 480 megawatts and functions as a storage power station that provides valuable peak electricity. A first extension of the facilities was already begun in 2009 with the start-up of the Tierfehd pumped-storage plant. For three years, work has also been progressing on another pumped-storage unit as part of the spectacular large-scale project “Linthal 2015”. Once completed, it will boost the total capacity of the facility to 1,480 megawatts.

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ith the launch of Project Linthal 2015, the management of Kraftwerke Linth-Limmern AG (KLL) marked their commitment to ensuring the sustained supply of electricity in Switzerland. KLL is owned jointly by the canton of Glarus (15%) and utility operator Axpo (85%). Budgeted at CHF 2.1 billion, the project calls for a new pumped-storage plant with four machine sets, the first of which is already scheduled for connection to the grid by the end of 2015.

COMPLEX EXISTING FACILITIES WITH THREE POWER PLANTS The currently operational facilities include the Muttsee, Tierfehd and Linthal power stations. The Muttsee plant utilises the natural water body of the Muttsee, which is situated

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at 2,446 m above sea level, for producing its maximum annual output of 4.4 megawatts. The control centre is located in a rock-cut cavern, from where the water flows down into the Limmernsee, which lies at 1,857 m above sea level. The Tierfehd power station has two levels: the first level processes the water from the Limmernsee, whereas the second level uses the water from the Hintersand compensating reservoir (1,298 m a.s.l.); together they generate a rated output of 301 megawatts. After passing through the power house, the motive water is guided into the Tierfehd reservoir (811 m a.s.l.), and the water from the Hintersand reservoir can be pumped into the Limmernsee at off-peak times. The Tierfehd pumped-storage plant, which began operations in 2009, uses the existing Limmern pressure system. Its machine set

delivers a maximum of 140 megawatts in turbine/pumped operating mode. In doing so, the Tierfehd power station utilises the 135 metre drop between the compensating reservoirs of Tierfehd and Linthal. After contributing to the power station’s 34.4 megawatts of annual output, the water flows back to the compensating reservoir at 676 m above sea level, and on into the Linth river. NEW PUMPED-STORAGE PLANT TO GENERATE 1,000 MW OF POWER The new underground pumped-storage facilities Limmern will pump the water from the Limmernsee around 600 m uphill and back into the Muttsee for re-introduction into the power generating cycle. Divided into caverns for the machine and transformer units, the cavern control centre is


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HIGH DEMANDS ON LOGISTICS Projects such as Linthal 2015 pose a huge logistic challenge, not least because of the difficulties involved in transporting the construction material. To keep the impact on the environment and the local residents at an absolute minimum, required bulk material has been transported by rail to a specially constructed transshipment hall in Linthal since 2011 – an arrangement negotiated with the local government of Glarus. The complex construction work for this ‘project of the century’ was likewise subject to extremely high demands in terms of organisation and logistics. Up to 500 persons are working at the construction site around the clock in three daily shifts to complete the first milestone in the pumped-storage plant project by the end of 2015. To be able to navigate the mountainous region and transport the various tools and machinery to the construction sites, a sophisticated concept was implemented whose sheer size and scope dwarfs all previous undertakings of this sort by far.

on site of Ochsentäfli at the Limmernsee to the highest construction site on Muttenalp. Initially, this cableway was used primarily for removing the rock and other material from the excavation of the central control cavern and the various tunnels. Most of the excavated material is used for building the Muttsee dam wall. The cableways are also equipped with an additional cabin, which has a load capacity of up to 40 persons. The two heavy-duty cableways are a core element of the construction infrastructure and an essential link in the logistics chain of Project Linthal 2015. Until the planned further cable car – a funicular with a load-bearing capacity of 250 tons – is put in operation in the Tierfehd access tunnel as a means of transport to the subterranean central con-

Construction Cableway 2 enables the transport of construction material from “Ochsentäfli” at the Limmersee to the Muttenalp construction site at 2,500 m above sea level.

photo: Axpo

photo: Axpo

RECORD-SIZED CONSTRUCTION CABLEWAYS Garaventa AG, the industry specialist for aerial ropeway engineering, installed two heavy-duty high-load aerial cableways as a means of transportation for people, machines and material to the respective construction sites. The specs of these cableway giants are as follows: Since 2009, Construction Cableway 1, an aerial tramway, has been supporting the transport of material, heavy equipment and persons from the base station near Tierfehd to the so-called Kalktrittli, the entrance point of the transport tunnel to the Limmernsee. Operating 20 hours every day, the two cableways each transport standard loads of up to 25 tons, although in exceptional cases they can bear loads of up to 40 tonnes – a clear world record for this type of construction. A few months after the startup of the first construction cableway, the second one was put in operation, which now connects the central constructi-

The hydropower facilities of Linth-Limmern AG after their extension

graphics: Axpo

the core element of the new power plant complex. The huge machine cavern is organised into seven levels, which will house the pump turbines, upstream spherical vales and engine generators. This is also where the mountain station of the funicular will be installed, which leads up from the entrance of Access Tunnel 1 in Tierfehd. As of autumn 2013, the funicular can be used for transporting all machine parts and the transformers uphill. The transformer cavern will be home to the four machine transformers and the equipment for conducting the generated electricity to the grid. With the four vertical machine sets expected to deliver a pumping and turbine capacity of 1,000 MW, this should give KLL’s facilities an instant boost from today’s 480 to 1,480 MW.

The two heavy-duty cableway pulleys can transport exceptionally heavy loads of 30 40 tons to the various construction sites on the mountain.

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photo: Axpo

The new dam wall on the Muttenalp serves to raise the filling level of the Muttersee by 28 metres, which corresponds to an increase in storage volume of 16 million cubic metres.

photo: Axpo

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Excavating the machine cavern has been a crucial milestone in the part of the project that has been completed so far. It is this cavern where the turbines and generators will be installed.

trol cavern at around 1,700 m above sea level, the two construction cableways are the only way to reach the construction sites high up in the mountains. DIFFICULT CONDITIONS AT 2,500 METRES ABOVE SEA LEVEL Currently the construction site with the highest elevation is on the Muttenalp, where concrete is being poured to raise the 1 km long and up to 35 m high dam wall that is designed to achieve the planned water storage goal: raising the natural elevation of the Muttsee of 2,446 m a.s.l. to an elevation of 2,474 m a.s.l. This is to expand the current storage capacity of 9 million m3 to 25 million m3 in future. Muttenalp is also where current-

1) Access Tunnel 1 with funicular 2) Access Tunnel 2 3) Access Tunnel 0 4) Adit 1) 2) 3) 4)

Headrace pressure tunnel Surge tank Pressure shafts Tailrace pressure tunnel

3D-graphics: Axpo

1) Construction cableway 1 2) Construction cableway 2

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ly between 2,500 and 3,000 cubic metres of concrete are being poured every day to build the new dam wall, the first 500 m of which were scheduled for completion by the end of November 2012. Obviously, maintaining a construction site high up in the alps means being exposed to the caprices and unpredictability of the weather. Still, the 150 workers and specialists from all over Europe who are currently at the site are doing an excellent job in braving the rough, changeable conditions and are so far keeping well within the planned time schedule. Another feature of the Muttenalp are the workers’ living quarters – neatly arranged barracks that house up to 300 persons, as well as a separate canteen, which is open almost

around the clock to make sure the workers never go hungry. EXTENSIVE TUNNEL EXCAVATIONS FOR THE NEW POWER PLANT The two pressure shafts leading from the Muttsee down to the machine cavern of the Limmern pumped-storage plant were excavated, one after the other, using the same 5.2 m tunnel excavator. From the central control cavern, two underwater galleries around 500 m in length lead straight into the Limmernsee. Access to the central control cavern from the base station near Tierfehd is by way of Access Tunnel 1, which is around 4 km long and was excavated using a 8.0 m tunnel excavator. Equipped with its own


funicular, this will be serving as a transport tunnel from 2013. Heavylift specialist Baumann GmbH & Co. KG was contracted to lift the parts of the disassembled tunnel excavator out of the central control cavern by means of a 700-ton lifting rig, then load it onto their SPMT and transport it to the Ochsentäfeli. The transport distance was around 4 km, which included a 2.8 km stretch with 14% inclination. Meanwhile, work was begun to fit the inside of the pressure shafts with steel pipes, which had been bent, welded and prepared for transport in a production hall in Tierfehd over a period of around three years. 830 pipe sections altogether, each measuring 3m in length and up to 4.4 m in diameter, are required for the two pressure shafts of the Limmern pumped-storage power station. They are transported to the control valve assembly at 2.300 m above sea level by way of Construction Cableways 1 and 2. Here three pipe sections each are welded together to form 9 m long units, which are then lowered into the pressure shafts from above.

photo: Axpo

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NEW 380-KV LINE FOR GRID CONNECTION Meanwhile the currently used compensating reservoir in Tierfehd was complemented by a further reservoir to the north of the powerhouse. This way, the storage capacity can be increased by 350,000 cubic metres to a total of around 560,000 cubic metres of water. The massive increase in output achieved under Project Linthal 2015 means that the facilities must be connected to Switzerland’s extra-high voltage grid. Today there is an overhead wire connection that leads from Tierfehd to the Grynau region near Uznach. The Linthal 2015 project calls for an additional 380 kV overhead line from Tierfehd to the Schwanden/Sool region, where it will be connected to the existing 380 kV line.

opportunity to provide their input to project consultancy groups, and they also contributed actively to protection and utilisation planning. “Working together with government agencies, associations and the public from the very early stages of the project made the whole planning and approval process very smooth and efficient for us. We were very happy about this indeed,” says Rolf W. Mathis.

COOPERATION FOR A WELL-BALANCED SOLUTION In Switzerland, large-scale infrastructure projects are not always easy to manage, as negotiating between the various stakeholders often makes it difficult to get things done. Project Linthal 2015, on the other hand, is considered an example of excellent cooperation between the building contractor and stakeholders in a hydropower construction project. “In our experience, including all interest groups in the process right from the beginning makes is much more likely that the project will be completed successfully,” explains Rolf W. Mathis, head of the Hydraulic Energy division at Axpo. Environmental organisations were given the

This impressive tunnel excavator was used for excavating Access Tunnel 1, which leads from the base station to the central control cavern.

OPTIMISM DESPITE CRITICISM According to some experts, the strong growth in solar and wind-powered energy production in Germany has had a negative effect on the business model of pumped-storage power plants. The reason for this is the fact that the different in profit between selling cheap electricity from pumped storage plants and selling peak electricity has been shrinking due to falling commercial electricity rates. This is why Project Linthal 2015 also met with a certain share of criticism and doubt regarding the profitability of the CHF 2 billion project. However, those in charge of extension project Linthal 2015 are still confident that, based on an investment period of 80 years, the new pumped-storage plant in Limmern can be operated profitably in the long run. They also point to the staunch pioneering spirit of previous generations, who provided a solid, valuable foundation for Project Linthal 2015 already in the 50s and 60s of the last century when they implemented the LinthLimmern power station.

Fü rs S c h w e rs t e g u t B e s t wh e n i t ge t s h e avy

Viktor Baumann GmbH & Co. KG Siemenacker 12 · D-53332 Bornheim-Hersel Tel. 02222 8303-0 · www.viktor-baumann.de

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photo credits: zek

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Textile manufacturer Moessmer is the oldest traditional manufacturing operation in the South Tyrolean Puster Valley. Today, like back then, the firm is committed to the utilisation of hydropower

OLDEST INDUSTRIAL OPERATION OF THE PUSTER VALLEY OPENS NEW CHAPTER IN HYDROPOWER UTILISATION As it did in the past, textile manufacturer Moessmer of Bruneck is committed to the use of hydropower. As the oldest industrial operation in the Puster Valley, the firm’s tradition-steeped history goes back more than 100 years. Over the last few months the current facilities were subjected to a comprehensive modernisation process, fitting them with the latest technical equipment. Thanks to a newly granted permit, the existing solution with two machines from the early 1980s was able to be updated to a GHE-PIT turbine solution with considerably higher output. The conversion on the premises of the textile factory turned out to be a complex challenge both for the planners and the construction engineers. In the end, they were able to keep within schedule. As a result, clean electricity has been generated on the Moessmer textile factory grounds since the end of last year.

T

hey count designer fashion labels such as Prada, Armani, Dolce & Gabbana or Louis Vuitton among their clientele. Superior quality, produced with sustainable manufacturing processes that reflect a successful symbiosis of tradition and modern style, has long been the hallmark of fabrics by Moessmer, one of the very few textile manufacturers in the Alps that still covers the entire production process from wool to top-quality fabric. Production has been up and running in Bruneck since 1894, making the factory the Puster Valley’s very first industrial operation – and a highly successful one to boot, as Moessmer was already appointed supplier to the Austrian imperial court by the turn of the century. The brand quickly took root and was destined for further success, despite the turmoil of the two world wars, turbulent market developments and changes in ownership. What remained was the backbone of the firm’s manufacturing power: the hydropower, which the owners still rely on as they did back then. “The reason why the factory was established here in Bruneck in the 1890s can be found in Rienz. They used the force of the moving waters to drive the mechanical equipment by means of transmissions. Years later, in 1923, the first power station was built, which provided around 220 kW,” says Dr Josef Zingerle, Head of Controlling at Moessmer. The start of the factory’s independent electricity generation was a milestone in

the firm’s history, as Zingerle explains. “In the early 1980s the power station was completely refurbished. They installed two Kaplan turbines, which were still in operation until June last year.” What was to follow was a new chapter in the history of hydropower generation at Moessmer. PROBLEMS WITH HIGHER WATER VOLUMES In 2010 the permit for the Moessmer power station expired, and to get the much needed extension called for swift action. The idea was to come up with a new concept in order to be able to accommodate new, future requirements as well as the changed basic conditions. These concern primarily the operation of the “Bruneck” upstream plant, which was constructed back in the late 1950s. Says Zingerle, “Until 2002 or 2033, the water was usually available to our turbines around the clock. But from then on, the operator adjusted the production to the economic electricity rates at the Energy Exchange. This means that the motive water began arriving at irregular peaks. On the one hand, our turbines were not designed to handle the higher water volumes, which means that quite a bit of the water remained unused. On the other hand, the two machine units were unable to react quickly to the constant changes. If you consider that at low levels the water often wasn’t available for more than three or four hours at a time, while the turbines took

about thirty or forty minutes to synchronise for parallel grid operation, you can imagine that the whole operation wasn’t always running very efficiently at all.”

ONE GHE-PIT TURBINE TO REPLACE TWO KAPLAN ONES In practice, this means that the design flow rate of previously 18,300 l/s would have to be adjusted to that of the upstream plant, which was 22,000 l/s. Besides, it was also necessary to find the machine solution that would provide the best outcome in terms of technology, economy and ecology. After intensive deliberations and research on various possible arrangements on the part of the owner and contracted planning office Studio G of Bruneck, the final decision came out in favour of a Kaplan-Pit turbine, which owes its name to the term for a shaft with an open top. Its excellent controllability and superior efficiency, combined with its low space requirements, were the most convincing arguments that sealed the decision in favour of this machine version. Where to obtain such a machine was decided rather quickly when the contract was put up for tender early last year. It was decided to award the contract for the electromechanical equipment to Upper Austrian hydropower engineering specialist GHE (Global Hydro Energy), which also enjoys an excellent reputation as an expert in Kaplan-Pit turbines. April 2013

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photo credits: zek

photo credits: zek

The turbine by GHE is designed for a flow capacity of 22 m3/sec. Its main characteristics are a high efficiency and excellent controllability.

graphic: GHE

Schematic graphic of the machine installation site.

To protect it against cavitations, the new machine unit has been lowered in elevation by 3.1 m. Picture: engine and generator

“We had had excellent collaboration experience with GHE in the past, so we were confident that they were up for it. Where quality was concerned we really had a lot of confidence. On the other hand, however, it was also extremely important for us to have a partner that would be able to deliver just in time – and demonstrate handshake qualities at the same time. In both respects, GHE has fully lived up to our expectations,” as Studio G’s panning team confirms. HIGH-SPEED CONSTRUCTION PROJECT Especially the time schedule represented a central criterion for getting the new power plant up and running. After all – as in many other Italian hydropower construction projects that year – the main goal in terms of time was to complete the entire modification and reactivation before the year was out. It was a tough challenge, considering that the plans called for particularly sensitive constructional measures – and that while the textile manufacturing operation had to be kept running. Once the new permit was obtained (this one will be valid until 2040), the earth was broken and the project kicked off in late June last year. The old machine units were dismantled, the old power house was knocked down, and preparations for the actual civil engineering work were begun. The contracted building firms saw themselves up against a very tight schedule from the very start. After all, the existing facilities had two machine units installed, which had required the construction of two separate tailraces, which were around 170 m apart. “Due to the difference in altitude between the tailraces the overall efficiency of the facility was not quite optimal, especially since the larger ones of the two machines – the one whose tailrace was further upstream – also had a lower gross head. So the obvious thing to do was to use the lower tailrace for the newly installed turbine,”explain the planners of Studio G. “In effect, this means that the higher one of the existing tailraces had to be brought down, while the lower one had to be expanded and adapted to the 22 m3/sec water flow.”

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SPECIAL CIVIL ENGINEERING MEETS JET GROUTING The expansion pushed the planners and construction specialists to their very limits, Due to the static conditions and restricted space conditions, the cross-section of the tailrace could be expanded only by lowering, but not by widening. To ensure a properly safe extension of the outer walls down to the required depth, the team decided to use a method known as “jet grouting” – a special engineering method that allows for setting up underground concrete structures by means of a high-pressure injection technique. During the procedure, an injection pipe is inserted into the ground. Once the proper depth is reached, a mineral compound is squirted in at extremely high pressures of up to 600 bar, which binds to the soil to form a solid concrete body. The rotating motion when the pipe is lifted out creates a concrete cylinder. Placed next to each other, these can be used to form regular underground walls without the need to dig up the soil. There are many advantages to this construction method: for one thing, it allows for the use of small machines, which can work even under very restricted spatial conditions; what is more, the ‘jet stream method’, as it is also known, has both a static and sealing function, which was particularly important for the Moessmer hydropower project. As a result, not only could the side walls be stabilised with a solid foundation, but the construction pit could be sealed more densely as well. Especially the latter was of critical importance for the subsequent construction of the new power house. “By the time we could start building the power house, we were 11 m below ground-water level. Here, again, we used jet grouting to create a sealed construction pit. It all worked very well,” recall the Studio G engineers. The base plate for the tailrace was also constructed by jet grouting. The concrete base, which is now situated around 4 m lower, was therefore prepared underground, with the soil above it being removed only later on. INNOVATION IN HYDRO-STEEL ENGINEERING The next construction steps required the intake channel to be adjusted top the new conditions along a 28 m stretch. This was done by gradual-


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Jet grouting preparations are under way.

Everything’s ready for jet grouting. This involves a concrete suspension being injected into the soil by means of a thin pipe.

photo credits: GHE

UNBUREAUCRATIC SUPPORT Technically, the lowering of the tailrace and the construction of the power house posed the greatest challenges for everyone involved – especially since the entire project had to be completed within a few short months. With the actual starting shot to the project being fired in late June of last year, the engineers could begin with the installation of the machine in late autumn – exactly as planned. This alone is reason enough for the engineers of Studio G to commend the contracted firms and the owner for their commitment: “Both representatives of the owner, Dr Niedermair and Dr Zingerle, were often at the construction site, and they contributed very actively to the project. We also commend the contracted firms for keeping the schedule the way they did, and for their competent way of handling the project.” A rather important issue for the construction part of the project arose in connection with the intake. The plans called for the newly build power plant contributing to the electricity grid of the Bruneck Public Utilities. That raised the

photo credits: Studio G

photo credits: Studio G

ly reducing its cross-section as it approaches the turbine. One question arose in connection with the design of the power house: due to the lower elevation of the installation site for the new machine, the engineers dispensed with the usual roof construction. Instead, the Studio G engineers planned a concrete ceiling just above the edge of the terrain. For mounting and maintenance purposes, a 6 m x 4 m, double slidable steel cover was placed onto the insert opening, which can be shifted very easily by hand. This solution was implemented by South Tyrolean steelwork engineering specialist Wild Metal, which had been awarded the contract for all steel construction and hydraulic steelwork engineering for the project. Their task gave the steelwork engineers from Ratschings the opportunity to prove yet again their reputation for being extremely inventive and resourceful. Numerous designs were constructed in three dimensions by Wild’s in-house construction department and quickly issued to the manufacturing department and partner firms. Highlights of their engineering ingenuity include the turbine pit, which is 8.5 m long and 3.6 m wide, as well as the reinforcing ring, which measures 4 m in diameter and whose contact surface with the guide vane assembly was engineered to an extreme level of precision. For the sluice gate at the intake, which has a width of 8.2 m and height of 3 m, the hydraulic cylinders were arranged so that they hardly reach above the sluice body. The downstream gate was anchored so deeply that the corresponding 10 m frame also remains almost fully hidden. A pressure-tight, cylindrical access shaft with hydraulically optimised bottom (also by Wild) was inserted into the suction pipe. The construction was complemented by some made-to-measure covers, as well as the railing and access ladders for the pit and turbine shaft, and the creatively designed spiral staircase, which provides access to the central level. An indoor crane – a special construction by Wild Metal – allows for controlling the guide vane system, which measures 3.6 m in diameter, in a space with only 4.7 m head clearance. The space between the twin crane car and ceiling is only 5 cm.

The suction pipe form work is finished, as is the pit casing by Wild Metal.

Wild Metal GmbH • Hydraulic steel constructions • Patented Coanda-system GRIZZLY • Trash rack cleaner • Gate • Security valve • Water intake rake • Complete water intake systems made of steel Wild Metal GmbH • Handwerkerzone Mareit Nr. 6 39040 Ratschings (BZ) • Italy

Tel. +39 0472 759023

www.wild-metal.com

Fax +39 0472 759263

info@wild-metal.com

We clean water April 2013

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photo credits: Wild

photo credits: zek

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Only the fine-screen trash rack was kept; the sluice gate was completely remanufactured by Wild Metal. Characteristically, are is no guiding rods for the gate sticking up in the air – again, this is a technical innovation by Wild.

The indoor crane, which was specially constructed by Wild, allows for lifting the 3.6 m guide vane assembly in a restricted space with only 4.7 m head clearance.

question of whether it would be possible to get the grid hookup up and running within such a short time. “We were very happy to see that the Public Utilities people were very helpful and unbureaucratic. As a result, we were able to start up operations right on time,” say the Studio G engineers.

SLOW RUNNER WITH CONVINCING QUALITIES Full of suspense, the owner and planners awaited the premiere ‘performance’ of the new turbine, which was lowered by 3.1 m to protect it against cavitations. The Pit-Kaplan turbine has several benefits for this type of application. Apart from its modest space requirements, it provides higher full-load efficiency in arrangements with a low head than vertical Kaplan turbines. Also, this type of turbine is usually highly reliable. Besides all that, it also provides easy access for maintenance, repair and inspection purposes. To top it off, the fast, efficient control of this turbine

makes it the ideal choice for applications like the Moessmer project. All these quality features are packed into the Pit-Kaplan turbines by GHE. Hundreds of reference facilities all over the world testify to their popularity. Compared to the previously installed turbines, the new one is a real ‘slow runner’, whose rotor moves at a very moderate 190 rpm. A spur wheel gearing transmits the rotational speed to 750 rpm. This arrangement was well calculated: after all, the intermediary gearing reduces the efficiency loss to only around 1 per cent. This is a record number – and a great argument in favour of the spur wheel gearings by Eisenbeiss, which are specifically designed for Pit-Kaplan turbines. At 750 rpm, the turbine drives the generator (manufactured by Hitzinger), which is designed for a rated output of 1,500 kVA. The turbine’s capacity at a net head of 6.70 m and maximum design flow rate of 22 m3/sec is 1,353 kW – a value that can hardly be achieved during the winter season, when the water levels are low.

QUICK REATCION TO CHANGING WATER VOLUMES More significant, however, is the rated medium output as referenced to a medium design flow rate of 11 m3/sec. Under these conditions, the two old turbines generated around 308 kW and 324 kW, respectively. By comparison, the rated medium output of the new turbine is now 832 kW. This sharp increase has several reasons: “One reason, of course, lies in the fact that the tailrace of the larger of the two machines was further upstream, which means it had a lower gross head. The new turbine now has the gross head of the lower one of the two machines. Another reason can be found in the excellent hydraulic design of the GHE turbine, which achieves very high efficiency levels to start with. However, there is another factor that comes into play where the overall efficiency of the facility is concerned: the new machine offers very good control qualities, reacts quickly to changing water volumes, and syn-

99 per cent efficiency with spur wheel gearings for Pit-Kaplan turbines Slowly moving Kaplan turbines often make it impossible to transmit the relatively low rotational speed of the turbine to the faster speed of a generator. In these cases, the operator needs to consider carefully the difference (loss) in efficiency by the introduction of a transmission gearing between the two components. In view of the special design of the Pit turbines, the gearings used to increase the rotational speed must meet very specific requirements. Besides requiring a compact construction to fit into the turbine shaft, they also need a smooth transfer of the turbine drive to the gearing. The additionally required high efficiency for such gearings require specialised solutions. Gearings by long-standing Upper Austrian-based manufacturer Eisenbeiss of Enns are designed specifically for this purpose and have been proven in numerous installations all over the world.

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Developed specifically for pit turbines, these gears are of robust, compact design and are approximately 99% efficient. This is achieved by means of a double helical toothing optimized for this particular application, low-friction bearings and an optimum lubrication regime. In conjunction with a gear system support halfway along the shaft, a cleverly constructed ribbing transfers the forces from the turbine straight Austrian-based spur wheel to the foundation. gearing specialist EisenAs a result, flexubeiss has developed ral stresses in the gearings that meet the specific requirements of housing are avoiPit-Kaplan turbines. ded, and excellent Thanks to their special double helical toothing and tooth meshing is high-grade design, they guaranteed even achieve efficiency levels of up to 99 per cent. at maximum load.


efficiency [%]

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Efficiency performance of the Eisenbeiss spur wheel gearings depending on the load of the turbine. [graphic: Eisenbeiss]

chronises within a very short time for parallel grid operation. This process, which used to take between thirty and forty minutes, now usually takes less than sixty seconds. With frequently changing water volumes, this is a key criterium,� say the planners of Studio G. The turbine control assembly was also provided by GHE. It is based on the highly proven, custom configurable HEROS control unit, which offers a characteristically high level of operating convenience.

ADAPTATION OF THE INTAKE CONSTRUCTION The start of regular operation of the facilities went ahead on schedule last December. Since then, the power station has been working reliably, its high efficiency rates confirming to the operator that they made the right decision – even if the machine has been running mostly on partial load, due to the seasonal water conditions. “After the necessary adjustments, the new machine unit is now living up to all our expectations. What helped shape our decision to go with GHE was the assurance of a guaranteed service over the next years. We will soon see how the output will change during the water melting season. The overall annual production depends essentially on the prouction of the upstream station,� explains Dr. Zingerle. Even if the heart of the facility is already pumping at a healthy beat, the overall project “Moessmer Power Station� is not quite finished yet. The to-do list still has a few as yet unfinished items on it, including the renewal and adaptation of the intake construction, which is situated around 250 m above the power station. The main objective there is to implement the ecological regulations and high-water safety standards, Studio G will once again play a leading role in making it all happen. PERFECT SYNERGY BETWEEN TRADITION AND NEW TECHNOLOGY The managers of the renowned textile manufacturer can consider their reconstruction project a true success – and with good reason: as plan-

Everyone involved in the project approached the renovation of the Moessmer power station with great dedication and enthusiasm: DI Adolf Dengg (Studio G), Dr Josef Zingerle (Moessmer), Philipp Meindl (GHE) and Ing. Thomas Eder (GHE).

ned, the reconstruction work, which involved clearing some complex administrative hurdles, was completed in record time. It was only around six months that the factory had to make do without its own hydro-powered electricity supply. Now, the path has been cleared towards a reliable, efficient operation until the current permit expires, i.e. 2040. As 120 years ago, when the first water usage permit was granted for the manufacturing location in Bruneck, hydropower is still a part of the Moessmer operations that no one would want to do without. And what would fit the mission of the Puster Valley’s oldest industrial enterprise better than hydropower – the epitome of traditional and modernity in perfect unity. Just like the textile factory itself.

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Technical Data w w w w w w w

Flow Rate: 22 m3/s Turbine: Pit Kaplan turbine Turbine Output: 1’353 kW Rotation speed: 190 rpm Generator: Synchronous generator Rotation speed Generator: 750 rpm Gear: spur gear (Eisenbeiss)

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Net Head: 6.70 m Manufacturer: GHE Number of blades: 4 Runner diameter: 2050 mm Manufacturer: Hitzinger Output: 1’500 kVA gear ratio: 1 : 3.947

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April 2013

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photo credits: Troyer

The power house for the new hydropower station was erected at the shores of the Vernagtsee at around 1,690 m above sea level

GLACIER WATER DRIVES NEW HYDROPOWER PLANT AT VERNAGTSEE Ever since Schnalstaler Gletscherbahnen AG built a high-head hydropower plant at the Schnalserbach stream in Kurzras near the head of the South Tyrolean Schnalsertal (Val Senales in Italian), the operators of the plant in the picturesque side valley of the well-known Vinschgau region had been planning to build another plant further downstream. Today, a quarter century later, the plans have come to fruition, thanks to the cooperative efforts of the community of Schnals and SEL AG. Energie Schnals Konsortial-GmbH invested around 8 million euros into the construction of the hydropower plant, which uses two structurally identical machine units to generate around 13 gigawatts of electricity. The facilities have been fully up and running since June 2012. he highest situated aerial cableway in South Tyrol leads from Kurzras at the head of the valley up to Mount Hochjochfern in the Ötztal Valley, around 3,200 m above sea level. The region owes its worldwide fame not so much to its touristic attractiveness but rather to the discovery of the “mummy of the Hauslabjoch”, better known as “Ötzi”. No doubt the cableway up the glacier, which was built here in the first half of the 1970s, has contributed greatly to the touristic development of the Schnalsertal region. To supply the cableway with local electricity, a hydropower plant was erected around a decade after the cableway had commenced operation. The plant uses the water of the Schnalserbach stream, which flows down a 400 m head towards the two twin-jet Pelton turbines, enabling them to generate a combined output of around 3.2 megawatts. This plant is still an important contributing supplier of electricity to the Schnalstaler Gletscherbahnen.

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OPPORTUNITIES OPEN UP AS SEWAGE WORKS CLOSE DOWN The idea of using another gradient step down to the Vernagtsee for generating hydroelectricity was already being considered at the time. “There used to be a sewage works in the tailwater area of the Kurzras power station, which used the Schnalserbach as a receiving water course. This made it impossible to get the necessary building permission for a second power plant,” explains the town’s former mayor, Hubert Variola. “The opportunity came when the sewage plant was closed down and the sewage water from Kurzras could be redirected to the central sewage works in Schnals,” says Variola, who currently serves as chairman of the Supervisory Board of Energie Schnals Konsortial GmbH. Subject to the local regulations for environmentally compatible, nature and landscape friendly building construction, the project was given the green light by South Tyrolean authorities in 2008.

Experts in limnology (i.e., the study of fresh water bodies) and landscape preservation were consulted to help in working out the plans. Initially, the water rights were linked to the permission of the Gletscherbahnen, which is due to run out in 2015. This was unacceptable to the operators. They immediately appealed the decision, which was revised in their favour when they pleaded their case. In the end, they were grated a permission for 30 years. Regarding plant operations, the communal government finally negotiated a solid partnership with SEL AG, which now holds a 40% stake in Energie Schnals Konsortial GmbH. Like many other hydropower plants throughout South Tyrol, this one is now also operated by Hydros AG.

TIGHT SCHEDULE FOR CONSTRUCTION When construction was began in the summer of 2010, it was clear that the project would involve massive building and engineering


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MOTIVE WATER FROM TWO INTAKES Like the upstream hydropower plant in Kurzras, the new facilities of Schnals Energie Konsortial GmbH utilise the water of the Schnalserbach stream. The water is captured directly in the downstream area of the plant and guided to a reservoir by way of a non-pressurised DN1000 steel penstock. The 2,700 m3 reservoir was built underground, with only a slight elevation in the hilly Kurzras landscape hinting at its existence. “Having it above ground wasn’t an option,” as the planning engineer explains, “because of our landscape preservation laws”. From the reservoir, the motive water is guided through a 2,500 m long DN700 drain pipe to the pipe intersection, where a Y-pipe section combines this stream with the water from the Lagaunbach. The

The core of the facilities consists of two structurally identical machine units, which deliver around 12 million kWh of clean electricity in a normal year.

photo credits: Troyer

work. “The Schnalserbach intake lies at around 2,150 m above sea level. This gave us only a very narrow time window to complete our work during the warm season. In view of this situation, construction work was contracted out to several firms so that they could work the various construction sites in parallel. As a result, the teams were working up to ten machines at the same time,” says Dr. Ing. Peter Pohl of the Pohl engineering team from Kastelbell.

latter flows to the intersection through a 1,150 m DN500 penstock. The combined motive water stream is then fed to the power house at the shores of the picturesque Vernagtsee by way of a 1,400 m DN800 penstock. This way, the power station is supplied with motive water from two intakes.

DUCTILE CAST IRON PIPES USED A total of 5 km of penstock piping was installed for the new hydropower plant. The products used for this purpose are ductile cast

iron pipe systems by Duktus. There are specific reasons for that. “To us it was important that the pipes had to be easy to install – more or less independent of the weather situation – to help us keep to our schedule. That was just one of the reasons why we went for the Duktus cast iron pipes,” explains Pohl. Another reason was the comparatively small trench size. Says Pohl, “We also had to dig the channel, which gave us quite a bit of excavation work to do. With that in mind, it was essential to keep the earth-moving work wit-

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photo credits: Duktuus

hin reasonable limits and avoid disturbing the landscape unnecessarily.” Depending on the inclination of the terrain, the engineers used classic pipe sockets or longitudinally stable Class K9 – K12 BLS® socket joints.

The penstocks are constructed from ductile cast iron pipes (by Duktus) with an inside protecting layer of alumina refractory concrete.

photo credits: Duktuus

Most of the piping was installed along the road – 5 km in total.

Technical characteristics w w w w w w w w w w w w w w w

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Design flow rate (total): 1.5 m3/s Net head: 255.26 m Turbine: 2 twin-jet Pelton turbines Design flow rate per turbine: 750 l/s Turbine capacity: 1,700 kW each Manufacturer: Troyer Nominal rotational speed: 750 rpm Generator: Synchronous generator Manufacturer: WKV (Wasserkraft Volk AG) Rated apparent power: 2,000 kVA Penstock: Ductile cast iron Total length: approx. 5 km Manufacturer: Duktus DN700 - 2,500 m / DN500 - 1,150 m / DN800 - 1,400 m Standard capacity: approx. 12 GWh

April 2013

EFFECTIVE CORROSION PROTECTION “As for everyone in hydropower plant construction, our focus in this project was on ensuring a long lifespan of the materials, especially where the long penstocks are concerned. It’s a well-known fact that penstocks made from ductile cast iron usually keep for many decades. But in this case we had something else to take into consideration: the motive water has a low hardness level and a particularly low pH value, which means a relatively high acidity level. So, to protect the piping against corrosion we had to apply a durable inside protective layer. This is why we decided to go with the Duktus pipe systems with an added coating of alumina refractory concrete,” says Pohl. Large sections of the penstock pipework was installed underground beneath roads and paths. This sounds much easier than it turned out to be. Among other things, the engineers had to install three pipe bridges across various rifts and ditches. The longest of these measured a full 28 m in length. Still, the contracted firms all managed to keep to their schedules. “All the firms did an excellent job. They were able to complete the majority of the work between mid-June and late October. This made it possible for us to put one of the two machine units into partial operation already in summer 2011,” Variola recalls. ELECTRICITY FROM TWO MACHINE UNITS Where machine equipment was concerned, the operators favoured a solution with two machine units to be able to adapt to the seasonal fluctuations in available water resources. In particular, they selected two identical twin-jet Pelton turbines by Troyer AG, each with a design flow rate of 750 l/s at a net head of around 225 m. The two horizontally aligned machines generate a rated output of 1.7 megawatts each. Both turbines are coupled to a 750 rpm synchronous generator. The rated apparent power of the generators (made by WKV) is stated as 2,000 kVA. With the acquisition of this electrical machine equipment, the operators have made a solid investment in ultimate hydropower quality. Both turbines and generators stand for high output efficiency, durability and a long useful life. It was already apparent during the first season of operation that the machines do live up to the operators’ expectations. A particular characteristic of the WKV generators is the fact that they not only look powerful but are indeed extraordinarily powerful. A lot of material went into the construction of the housing and end shields, providing a solid basis for the overall durability and smooth operation of the machine. In particular, the combination of high-quality stator sheets and a sophisticated ventilation system ensures the high level of efficiency in this machine. WKV offers no “off the shelf ” generators. Every one of their machines is fine-tuned precisely to the specific application environment and the individual requirements for its intended purpose. The generators are therefore just as “tailor made” as the turbines.

DEPENDENT ON THE UPSTREAM PLANT While the new power station completed its first year in partial operation, it was waiting for the water from the Lagaunbach to awaken its yet dormant potential. After all, work on the supply intake at the Lagaunbach was not scheduled to complete before June 2012. But once the work was finished, the time had come: the new power station with its two machine units was finally able to switch into high gear and full operation. “The motive water from the Lagaunbach stream is very important for this power plant. It’s not just about the additional volume of water. The main point is that it makes the facilities independent from the production regime of the Kurzras plant. In accordance with the requirements of its operator, the cableway now receives its electricity from the upstream power plant. Thanks to a water reservoir,


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The longest of the three pipe bridges extends 28 m across a rift.

TURBINE BUCKETS PROTECTED AGAINST GLACIAL ABRASION By utilising the supply intake from the Lagaunbach in combination with the small daily storage reservoir downstream of the Kurzras plant, it was possible to minimise the hydro-peaking effect of the Schnalserbach – something quite undesirable, not least for ecological reasons. “The reservoir serves an important purpose. For one thing, it supports our demand-based production and allows us to plan efficiently in times of low water levels. On the other hand, it is essential for protecting our turbines. We know from experience with the upstream plant what kind of damage glacial abrasion can do to the Pelton buckets. It tends to wear out most conventional rotors within a single season. But we have our reservoir: this allows the fine-grained glacial sedi-

photo credit: Duktuus

the plant can generate both supply electricity and peak electricity, which means it is operated in hydro-peaking mode,” as Pohl explains. “Also, our reservoir allows us to generate peak electricity at the downstream facilities. But since the electricity that’s generated here is sold on the open market, the production curves of the two plants are not synchronised very well. That doesn’t always make things easy for the operator, Hydros GmbH.”

ment to settle, which prevents it from getting into the penstock,” explains Pohl. A first check of the rotor after its first year of operation confirmed the reservoir’s bucket protecting qualities. The verdict: no visible damage from glacial sediment. PEOPLE FOR HYDROPOWER For both the SEL AG and the community of Schnals the new power plant at the Vernagtsee has turned out to be a true success story. After all, it is by no means typical or expected for a local population to welcome hydropower projects like this one with an emphatic “yes” – especially at a place where only 60 years ago an

entire community was evacuated to make room for the artificial lake. Back then a largescale power plant was erected against the will of the people – a course of action that caused much suffering and has left scars on the souls of many locals that are still felt today. However, the new hydropower facilities were built with the consent of the people. Today they are actually proud of their new small-scale power station. Generating around 12 million kWh of clean electricity in a normal year, it will not only help to support and secure the energy supply to the Vinschgau region, but even provide a nice income for the local community as well.

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photo credits: Neithan90

photo credits: kgberger

HYDRO

The entrance to the mining shaft (“Rudolfschacht”) in Bad Bleiberg

Since time immemorial, 2.166 m high Mt Dobratsch has served as one of the most important drinking water reservoirs in the Austrian province of Carinthia.

AUSTRIA’S FIRST MINE-MOUTH POWER PLANT IS MINING ECO-POWER In the tradition-steeped Carinthian mining town of Bad Bleiberg there is a whiff of renaissance in the air. Not that the zinc and lead mining operations of yesteryear has been revived. But in view of the recent construction of Austria’s first mine-mouth power plant at 250 m below ground it would be no exaggeration to speak of a highly innovative re-use of closed-down mining cavities. Getting this small-scale power station built was no small feat. In addition to complex negotiations with the authorities it also required a series of special technical solutions. But in the end the efforts of project operator AAE Entwicklungs GmbH were crowned with success. The Bad Bleiberg hydropower station has been a reliable source of eco-power for about a year now, generating around 1.5 million kWh per normal year.

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water out of the tunnels. But this was when something extraordinary happened: the water turned out to be 28 °C warm thermal water. Along with the water, the basis for today’s spa and wellness tourism had emerged, eventually turning the catastrophe into a blessing. DRAINAGE INTO THE DRAU VALLEY The miners had almost reached sea level in their excavations into the depth. The “Rudolf Blindschacht” (underground tunnel), which was named after Austrian Crown Prince All water streams converge in a distribution system in the building of the Rudolfschacht.

photo credits: HOBAS

H

igh up in the mountain valley between Mounts Dobratsch and Erzberg in the Bleiberg region of Carinthia, the ground looks perforated like Swiss cheese. During the region’s mining history, which goes back more than 800 years, the miners have constructed an elaborate system of 1,300 shafts and tunnels with a total length of 1,200 km. Especially lead and zinc have been mined here since the second quarter of the fourteenth century. Back then, the mining industry was the economic backbone of the entire region. By the end of the eighteenth century, Bad Bleiberg had 4,000 inhabitants – a quarter more than today. The first sharp decline for mining came during the time of the big world economic crisis. In 1931 all mining activities were suspended for a whole year. But the most significant turning point in local mining history happened 20 years later, when excavation work at the twelfth run caused water to flood the tunnels at a rate of around 3,000 litres per second. The tunnel system was completely flooded up to the eighth run. It was a catastrophic situation, which the miners tried to remedy by means of the most advanced pumping technology available at the time. In the end, they actually succeeded in getting the

Rudolf, reached down 850 m to only 87 m above the Adriatic sea level. One of the most important tunnels – the “Kaiser Franz-Josef-Stollen”, took eighteen years to excavate: from 1894 until 1912. With a length of 12.8 km, it provides the essential connection between the Antoni shaft and the Drau valley. It was through this tunnel that the miners were able to drain all trapped water and most of the pumped water into the River Drau. This water was then used by the Töplitsch hydropower station to generate electricity. However, electricity was also generated inside the mine itself. A power station had been erected at the fifth run, around 250 m below ground. From 1918 onwards it provided the electricity needed to power the underground mining equipment. WATER DOWN THE DOBRATSCH All through the mining history of Bad Bleiberg, water has played a key role in local mining operations. One essential contributor to the water supply was nearby Mount Dobratsch, a 2,166 m mountain composed primarily of porous limestone, which has served as a source of drinking water for centuries. One of the mountain springs is the


photo credits: zek

photo credits: HOBAS

above-ground operations. They justified their decision by saying that in the case of shutdown mining sites like this it is not necessary to apply the regular mining regulations,” says Christoph Aste, who was finally handed the overall permission to go ahead with the hydropower project in 2009. Together with AAE Wasserkraft GmbH of KötschachMauthen (Carinthia), the project stakeholders founded AAE Entwicklungs GmbH, which was to complete the hydropower plant within around 16 months. USING DIFFERENT WATER SOURCES Christoph Aste’s ingenious concept not only called for the use of water from the Nötschbach spring, which may be used up to a volume of 100 litres per second, as per an age-old permission granted back in the old days of the mining operation. In addition to this water source, Aste’s plan included the use photo credits: zek

TOUGH NEGOTIATIONS FOR PERMISSION Credit for the idea of constructing a smallscale power station at the age-old mining site is due to Dipl. Ing. (Master of Engineering) Christoph Aste, who was the first to become aware of the site’s potential. Since 2004 he has been pursuing the project with great patience and persistence, clearing all the many administrative hurdles to finally obtain building permission. “Being able to re-use the shut-down mining areas in this case required a mining permission in addition to the usual water usage and electricity generating permits and licenses. That led to a whole series of problems: after all, the electrical norms and regulations under ground are completely different from the ones that apply above ground. It took us years to get all three permissions sorted out. In the end, it was the mining authorities who broke the ice, by granting a permit in accordance with the legal requirements for

HOBAS GRP (glass-fibre reinforced plastic) pipes in the building of the Rudolfschacht (top left). Installing the GRP pipework (bottom left) The bend of the GRP pipes was achieved through the use of angulated pipe sockets (centre). Right: A century-old grey cast iron pipe, which was manufactured in England in 1890. The socket consists of a layer of small wood panels (top).

photo credits: HOBAS

Nötschbach spring, which emanates at 1,015 m above sea level and delivers up to 500 litres per second when the water levels are high. This water used to be pressed towards the reverse slope to carry the water off via the Antoni Shaft towards the Drau Valley, but also to lead it into the Muskari reservoir. This reservoir has a capacity of 3,000 cubic metres and used to serve as a level sensor for the old small-scale hydropower station at the fifth run. The mining level is exactly the one that is still located just above the flooded tunnel system today. When the mining operation was shut down in 1993, more and more water kept seeping into the mine, eventually flooding the system up to the fifth run at around 250 m below ground level. Immediately beneath it, the water is carried towards the Drau Valley by way of the drainage tunnel.

photo credits: HOBAS

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Visit to the machine cavern 250 m below ground level: Michael Bader (EFG), DI Christoph Aste (Project Developer, Planner and Plant CoOperator), and Werner Goldberger (EFG Managing Director) (from left)

of water from the Muskari reservoir and all other mountain water sources that can be viably collected and led to the power station. A distribution system was to be installed at the entrance of the Rudolfschacht, which was to carry the water from all incoming sources to the penstock. The penstock itself was to lead straight down along the outer wall of the Rudolfschacht to the site of the old power station at the fifth run. The machine unit was to be installed at a depth of 250 m below ground level. This was not only to generate electricity, but had to be able to withstand the adverse conditions under ground for decades to come. The energy is carried away from the mountain on the low-voltage side. “Of course we could avoid conduction loss by increasing the high-voltage power,” explains Aste. “But we decided against this, for security reasons. After all, one has to consider that there is always the danger of water leakage. In the end, it would just be too dangerous.” ANCIENT PIPEWORK MEETS MODERN REPLACEMENT One of the first tasks in the project concerned the penstock from the Nötschbachquelle. The existing one was the original pipe that was laid in the 1890s. “The old DN360 penstock pipes made from English grey cast iron were quite extraordinary. Although their walls were only a little more than two and a half centimetres thick they were extremely solid and still in excellent condition. The pipe sockets are covered with small, chip-like larch wood panels, which swell up as they soak up the water. This way, they keep the connection tight as long as they remain soaked with water. We put the pipes to the test, and they proved to be literally airtight. So we left the April 2013

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EFG Project Manager Gero Pretis can look back in satisfaction on a successfully completed project.

lation was only allowed at night to avoid disturbing the spa guests in the nearby treatment tunnel at the first run.” Installation began at the bottom and proceeded upwards. The pipes were fastened into place by means of specially developed clamps and anchored to the walls of the Rudolfschacht with dowels. Although 20 cm dowels were sufficient for the deeper limestone layers, the layers closer to the top required the use of 2-metre anchors to fasten the penstock into place. “What really surprised us was that the shaft was not quite level, according to our measurements. This meant that the installation team had to expand the shaft with a jackhammer at one point,” as Christoph Aste recalls.

CERTIFIED MINING STAFF INSTALLS PENSTOCK In the shaft structures of the Rudolfschacht the transitional link to a cast iron pipe was installed in the form of a steel socket. From there, it leads off into an elbow and on to the penstock, which was made from ductile cast iron pipes by Duktus. The vertical installations were implemented using DN250 calibre pipes with a cement-mortar lining. “Using a larger dimension was simply out of the question, as we were already pushing the space limits,” says Aste, commenting on one of several difficulties the engineers encountered during the installation of the penstock. “Only authorised, certified mining personnel is allowed to perform installation work in the shafts. And even they kept running into all sorts of difficulties. The danger of falling rocks limits the ability for miners to work on different levels above each other, which also limits the size of the working teams to only a few people. Also, instal-

MACHINES, ‘TROPICAL STYLE’ The entire project was technically extremely demanding on everyone involved. Especially the core element of the facility, the turbine-andgenerator unit, had to be designed specifically to withstand the extreme conditions under ground. As EFG’s project leader Gero Pretis explains, “Due to the high humidity levels – around 90 per cent – the entire turbine had to be made from stainless steel. For the same reason, the generator by Hitzinger was delivered with an additional insulation for tropical climate conditions. It’s the only way to ensure reliable operation for decades to come.” As one might expect by now, transporting the machine unit to its destination turned out to be a difficult, extremely sensitive undertaking as well. Both the turbine and generator had to be hauled downwards by means of a cable winch. Especially moving the generator along its gui-

photo credits: EFG

old penstock in place down to the first low point,” says Aste. From this point onward, however, the engineers relied on the qualities of modern pipework engineering technology. A little downstream of the stream capture, near the culvert, the old pipes were cut off and replaced with GRP pipework (DN300, SN10.000, Pressure Rating PN16) by HOBAS. The pipe now covers the 980 m distance to the shaft building on the other side of the valley. Says Aste, “The HOBAS pipes allowed us to design a solution that is both highly functional and cost-efficient at the same time. Best of all, we hardly had to use any pre-shaped pieces. This is because we were able to achieve the necessary bends with angulated pipe sockets and cut-off pieces, which were pre-fabricated at the HOBAS production facilities. The people at HOBAS really helped us a great deal with that during the planning stage.”

WORKING UNDER EXTREME CONDITIONS Downhole work was generally hampered by a series of problems that power plant construction engineers would never encounter under normal conditions. Werner Goldberger, Managing Director of EFG of Feldkirchen, which supplied the electromechanical equipment, can tell a thing or two about it: “You had to climb around twelve hundred steps to get to the machine cavern. If you forgot something up there you just had to do without it. Even our most athletic colleagues were barely able to get there and back again more than once a day. As if that was not enough, communication was extremely difficult as well. It should have been possible to talk to colleagues in the machine cavern by walkie-talkie, but in practice the connection was anything but optimal. Working in a confined space in artificial light and extreme humidity 250 m below ground level took a lot out of our people. Their notebook computer stopped working after about half an hour. The conditions down there are really tough, especially considering that there is always the danger of the light failing. You have to keep your calm under any circumstances. Looking back, I can only say that it takes really well trained staff to do this kind of job – people who are used to coping with conditions like these.”

Technical characteristics w w w w w w w w w w

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Flow Rate: 120 l/s Net Head: 322 m Turbine: Pelton Turbine Nozzles quantity: 2 Manufacturer: EFG Turbine Capacity: 341 kW Rotation speed: 1’500 rpm Generator: Synchronous Generator Manufacturer: Hitzinger Average Energy Capacity: 1.5 GWh


photo credits: zek

HYDRO

Project Developer Dipl. Ing. Christoph Aste and Michael Bader (EFG) performing the monthly inspection of the machine unit.

ding tracks did not work out as expected, but the efforts were finally crowned with success. Once delivered safely to the bottom of the pit, the generator had to be transported around a hundred metres through the kneedeep water of the Franz-Josef-Stollen to the machine cavern. To protect the machine against the water, it was hauled onto a watertight transport tub, which in turn was placed onto an old mining tram. Packed onto the old transport vehicle, the generator finally made its way through the water into the dry machine cavern. “All in all, it’s fair to say that as far as workflow is concerned we have entered a lot of new territory. Fortunately, there were no real accidents, and nobody was hurt,” says Aste. 1.5 GWH IN A NORMAL YEAR Having started work in May 2010, the project team was able to complete their power plant project by September 2011. Today, after more

than a year in operation, the facility has proven itself to live up fully to everyone’s expectations. In a normal year, the power station, which is officially known as “Kraftwerk Nötschbachquelle-Rudolfschacht”, will feed around 1.5 million kWh into the grid of electricity provider KELAG. The twin-jet Pelton turbine by EFG is designed for a capacity of 341 kW at a net head of 326 m and a flow capacity of 120 l/sec. The “made in Carinthia” turbine will drive a brushless Hitzinger synchronous generator at a nominal rotational speed of 1,500 rpm. DOUBLE USE FOR THERMAL WATER Among the other hydropower plants operated by AAE, the new Nötschbach plant stands out not just for its 1.5 million kWh generating capacity. It special qualities lie rather in the fact that it can provide buffered energy to cover peaks within the grid, thus contributing to an evenly sustained supply of electricity.

To boost these particular qualities even further, project developer Christoph Aste has plans for a further extension of the water utilisation concept at hand: he intends to utilise the thermal water as well – and do so in two ways. At a pressure of 17 bar the thermal water is pumped upwards to the fifth run. “Since the water has a temperature of 28 degrees, we intend to move it all the way up to use its thermal capacity for long-distance heating purposes. The used water will then be fed back into the penstock. This allows us to kill two birds with one stone: we’ll be able to use the water for heating via a heat pump while increasing the annual output of our plant,” says Aste. PROTOTYPE WITH IMITATION POTENTIAL Installing power plants in mountain caverns is not a new concept any more. In fact, there seems to be a certain trend towards this type of installation. However, installing a power station inside a closed-down mine is something that has never been done before in Austria. In this sense, the Nötschbach power station serves as a prototype for a hydropower engineering concept that might set a trend for further projects in the future. Says Christoph Aste, “There are lots of closed-down mines here in the Alps that could be developed into hydropower sites based on a similar concept. One mustn’t forget, many of the issues that can be a real headache for power plant engineers – things such as ecologic concerns, residual water volumes, the interests of local residents, noise and so on – are all irrelevant underground. Of course, we will pass on the know-how that we have gained here to others. However, what would be needed now is a comprehensive potential analysis of these type of projects.”

GRP Hydropower Pipe Lines O O O O O O O O

Minimal friction and pressure loss Less water hammer High abrasion resistance Corrosion resistance UV light resistance Angular deflection Low operating an maintenance costs Long service life

E Rohre GmbH Wietersdorf 1 | 9373 Klein St. Paul | Austria | T +43.4264.2852.0 | F +43.4264.2852.2045 | www.hobas.at

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SMALL HYDROPOWER PLANT IN CHILE WITH OSSBERGER CROSS-FLOW TURBINES

I

n 2004 Chile had to deal with problems caused by its growing dependence on energy imports when gas deliveries from Argentina stopped and the country experienced a shortage in its electricity supply. This situation resulted in a new energy policy focusing more strongly on energy efficiency and renewable energy sources.

graphic: Ossberger

NEW LAW HELPS SMALL HYDROPOWER PROJECTS In recent years large hydropower projects have faced growing resistance from environ-

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photo: GPE

Since the 1990s the South American country of Chile in the Andes mountains has seen a rapid economic development. This economic growth is accompanied by a growing energy demand, which currently increases at an annual rate of eight percent. According to Chilean President Sebastian Pinera it will take an expansion of the country's installed hydropower output from currently 17 GW to 25 GW to satisfy the growing energy demand until 2020. Chile's energy matrix shows that about 60 percent of the country's demand is covered by fossil fuels, of which almost the entire supply has to be imported. The remaining 40 percent of demand is met by renewable energy sources. Hydropower accounts for about 35 percent, and therefore the lion's share, making it the most important source of electricity produced from the country's own resources.

The core of the small hydropower plant on the Chilean Río Allipén are 2 Ossberger cross-flow turbines identical in construction with a maximum capacity of 9.0 m3/s each.

mental protection activists. In 2004 the Chilean government provided support even for small hydropower projects with a new legislation: the laws “Ley Corta 1” and “Ley Corta 2” support and facilitate a profitable operation of small hydropower plants. Thanks to these legal simplifications and facilitations a small but interesting hydropower plant project was realized near the city of Cunco in the Araucanía Region last year. Bavarian turbine manufacturer Ossberger provided its renowned cross-flow turbines including the clever SCADA control system.

The fully automatic SCADA control system by Ossberger controls and monitors both turbines.

April 2013

DIVERSION POWER PLANT ON AN IRRIGATION CHANNEL The new hydropower plant was constructed on a 5 km long irrigation channel, which deducts a water volume of 18 m3/s from the Río Allipén. Depending on the season the river carries a water volume of 100 m3/s up to 1,000 m3/s. During the summer months the water of the channel is used to irrigate agricultural fields, while during the winter months the water is not needed by farmers. During this period or in longer rainy seasons the water of the channel is used to produce hydropower energy. The head at the end of the about 5 km long diversion channel measures 20 meters. SPECIALIST FOR HYDROPOWER FROM IRRIGATION SYSTEMS For the construction of the small hydropower plant a joint venture was founded by the Allipén irrigators collective, a collective of local farmers and operators of irrigation plants, and the Santiago de Chile–based company GPE (Gestión de Proyectos Eléctricos). The company specializes in developing and operating small power plants together with agricultural associations, such as the hydropower projects Huasco in Vallenar and Puclaro


photo: GPE

photo: GPE

HYDRO

After flowing through the inlet structure the process water is directed through a penstock to the new power house.

The coarse and fine rack in front of the inlet structure of the power plant

in La Serena, both positioned at the bottom of irrigation storage reservoirs, as well as the Mallarauco power plant, which was also built next to an irrigation channel. In general these projects bear more advantages for the Chilean agriculture than just supporting more than 120,000 farmers, who would not be able to realize such plants considering their low income. The farmers can still use the water at their disposal, they can make additional profit with the hydropower plant and they can, at least partly, invest in improvements of their existing irrigation systems. At the same time the local electrical grid is improved with the construction works of the plant. Chile has an extraordinarily great potential for such hydropower plants. Unfortunately there are huge differences of opinion within the irrigator collectives regarding these projects: 5060 members of the Puclaro collective had negotiated for more than three years until an agreement for the construction of the small hydropower plant was reached. OSSBERGER S TESTED SOLUTION FOR TURBINES Regarding the selection of a suitable turbine type the Chilean company GPE relied on the tried and tested cross-flow turbines manufactured by Ossberger. The operator saw the advantages of the cross-flow turbines by Ossberger in the small effort needed for the installation, the easy handling and easy maintenance as well as the turbines' good partload behavior. For the channel's total flow rate of 18.0 m3/s two crossflow turbines identical in construction were installed, which produce a nominal output of 1.48 MW each at a head of about 20 meters. The two synchronous generators manufactured by AEM Dessau have an output of 1.48 MVA each. For this plant Ossberger also delivered a SCADA system automatically controlling the two turbines. It enables monitoring and controlling not only on site but also over the internet with access being protected by passwords and authorization regulations.

relies on the technical know-how of its experienced European partners to promote the development of hydropower in the South American state of Chile with flagship projects, such as the power plant on the Allipén River.

Technical Data w Head:

20 m

w Design Flow:

18,0 m3/s

w Turbines:

2 x Cross-flow Turbines

w Manufacturer:

Ossberger

w Nominal Output:

2 x 1,48 MW

w Rotation Speed:

139 rpm

w Generators:

2 x Synchronous

w Manufacturer:

AEM Dessau

w Output:

2 x 1,48 MVA

GREAT POTENTIAL FOR SMALL HYDROPOWER PLANTS IN CHILE The construction works on the hydropower plant near Cunco on the Chilean Río Allipén took about one year. The plant was put into operation in May 2012 and has been running smoothly ever since, very much to the operators' satisfaction. In general there are a few adjustments and improvements to be made throughout Chile in order to increase the efficiency of the country's existing hydropower potential. GPE, a specialist for small power plants, April 2013

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photo credits: Lukas

HYDRO

The "Ratsmühle", which was purchased by Celle Town Council in 2009, was converted into a "green power plant" in 2012.

ECOLOGICAL MODEL POWER PLANT CREATED IN THE HEART OF THE TOWN OF CELLE The old "Ratsmühle", a former mill owned by the local council, in the centre of the Lower Saxony county town of Celle is a hydroelectric power site which is steeped in tradition and has a long history. From as early as the 14th century, this was home to water mills and hammer mills which were later converted and expanded to create a grain mill. Following a temporary shutdown in the 1980s, the hydroelectric power plant was then revitalised and started operating again in the mid-1990s. From 2011 to 2012, the "Ratsmühle" was once again modernised on behalf of Celle Town Council and converted into an ecological model power plant.

T

Parts of the fish protection grill with horizontal grill bars with a fish-belly profile and a gap of 15 mm between the bars.

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photo credits: Heidt & Peters

his is because the "Ratsmühle" hydroelectric power plant, which has been completely renovated, is the first power plant site in Lower Saxony that has both a fish ladder and a fish bypass as well as a fish protection grill. The plant was planned and its construction was supervised by the Lower Saxony State Agency for Water Management, Coastal Defence and Nature Conservation and Ingenieurgesellschaft Heidt & Peters mbH; all of the hydraulic steel construction was carried out by the Bavarian industry specialist LUKAS Anlagenbau from Waldthurn.

OPTIMISED TURBINE CONTROL SYSTEM INCREASES EFFICIENCY The machine unit for the "Ratsmühle" power plant consists of 3 Francis turbines, each with an output of 200 KW, which were completely overhauled during the course of the revitalisation. The units are now controlled via an optimised turbine control system and in this way, depending on the flow rate, always operated in the optimum efficiency ranges in single-machine or multiple-machine mode. An optimised gearbox was also fitted as part of the latest modernisation measures. EXTENSIVE HYDRO STEEL STRUCTURES WITH SPECIAL FUNCTIONS However, the centrepiece of the revitalisation of the plant was the extensive hydro steel structures. The company performing the work, LUKAS Anlagenbau, was responsible for planning, delivering and installing the hydro steel structure components and created a 19.6 m long horizontal fish protection grill, a bypass valve, a fish box channel for the fish bypass, a bottom outlet paddle with a back-up flap on it as well as a deflector beam which it is possible to walk along. The assembly of these parts of the plant was carried out swiftly from April to September 2012 and, during the course of this work, special assignments which are not encountered every day such as the screwing together of the accessible deflector beam in the water were also carried out. Equipped with just a pair of trunks and a size 30 spanner, the fitter summarily made his way into the River Aller and from there screwed together the 6 m long individual parts of the deflector beam. Even when additional concrete work


for the turbine inlet chamber became necessary and the installation of the hydro steel structures had to be interrupted at short notice, the timetable was still kept to and the work completed on schedule by the company LUKAS. INNOVATIVE SOLUTION FOR FISH BYPASS The client and sponsor of the entire project, the royal town of Celle, was keen right from the very outset to make sure that the revitalisation had a heavily ecological focus. The situation regarding the fish bypass in particular was solved in an elegant and above all effective way by the Heidt & Peters planning team led by Mr Schumacher: Normally the flush or sluice gate of a power plant is always closed and only opens when the trash rack cleaner switches on or floating debris is washed up. In this case, the sluice gate does not open from top to bottom, but rather opens to the side like a door and is approx. 15 cm open The fish can descend down into the lower water via this fish box channel.

SUSTAINABILITY OF THE PLANT THE TOP PRIORITY In order to minimise the hydraulic losses resulting from the inclined inflow of the grill, horizontal grill bars with an optimised fishbelly profile were fitted by the company LUKAS, with the distance of 15 mm between the bars being stipulated beforehand in consultation with the fishery biologists. The operator consciously accepts the loss of works water for the lock current and the hydraulic losses at the fish protection grill and thus lays down a clear marker that the powers that be from Celle Town Council pay more than just lip service to concepts such as sustainability and ecology. However, when commissioning took place, power outputs of 190 kW were still measured for each turbine, which demonstrates that, despite the great level of attention paid to the environment and nature, it was possible to keep the production losses to very manageable levels.

photo credits: Heidt & Peters

Fitters from the company LUKAS doing the final work on the accessible deflector beam.

RENEWABLE ENERGY ACT CRITERIA WERE MET Following all the efforts made in the area of the environment and sustainability, it is hardly surprising that the new plant meets the strict criteria of the German Renewable Energy Act and thus receives an increased level of feed-in compensation in accordance with the amendment to the German Renewable Energy Act in 2012. The ceremonial opening of the modernised "Ratsm端hle" hydroelectric power plant was performed in November by the Minister for Economic Affairs of the German State of Lower Saxony, Gert Lindemann, and in the presence of Celle's Mayor Dirk-Ulrich Mende as well as representatives of the council and administrative body the ecological model power plant was then handed over to its intended use. LUKAS Anlagenbau GmbH Albersrieth 27 D-92727 Waldthurn tel: +49 (0)9657 930-0 fax: +49 (0)9657 930-299 mail: lukas.alb@lukas-anlagenbau.de web: www.lukas-anlagenbau.de

The imposing horizontal trash rack with the trash rack cleaner shortly prior to commissioning.

photo credits: Heidt & Peters

The slightly opened sluice gate generates a constant lock current for the fish bypass.

all the way along. This generates a constant lock current for the fish in the direction of the sluice gate opening, and in addition the inclined position of the fish protection grill prevents the fish from flowing or being pushed against the front of the grill. Ultimately, the fish can glide unscathed down into the lower water via a box channel. For the fish ladder, a migration aid in the form of a vertical slot was implemented. This facility with a length of 150 m will ensure that the fish wanting to migrate in the River Aller can get from the lower water to the head water by passing through 37 basins. This represented another important step towards the planned reintroduction of salmon and sea trout to the Oberaller, Kleine Aller, Oker and Schunter rivers.

photo credits: Heidt & Peters

photo credits: Lukas

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photo credits: GHE

15 customised turbines from the company Global Hydro Energy for the Uz cascade power plant in Romania: There are 14 Francis turbines and one Pelton turbine in the power range of between 328 kW and 630 kW.

TURBINE POWER FROM UPPER AUSTRIA FOR POWER PLANT CHAIN IN ROMANIA For a number of years now, the Upper Austrian hydroelectric power specialist GHE (Global Hydro Energy) has been one of the best-established turbine suppliers in the booming market for hydroelectric power in Romania. GHE is currently supplying the equipment for an extensive cascade project in the valley of the River Uz in the Szeker Land region. Only recently, a total of 15 turbines for six power plants were delivered to the valley in the north-east of Transylvania, which is difficult to reach. The final mechanical assembly is currently in full swing. In just a few weeks, the first electricity is set to flow from the Uz cascade project.

T

he work on the Uz power plant project in Romania's Szeker Land region has extended over around three years. 300 workers were employed during this period in order to establish the structural foundations for a cascade plant comprising a total of 6 machine exchanges with 15 sets of machines. The power plant project on the River Uz in the valley of the same name, which is backed by the Hungarian-Romanian Hivatalos Srl. investor consortium, is regarded as an important step in the expansion of the hydroelectric power resources in the region. The rumoured level of investment is around 15 million euros.

photo credits: GHE

GREAT LOGISTICAL EFFORT IN A REMOTE REGION The project is now already in the final phase. Since the end of January, the assembly work has been in full swing despite all the adverse weat-

The The turbines turbines are are made made ready ready for for transtransportation portation at at the the GHE GHE factory factory in in Niederranna. Niederranna.

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her conditions. The assembly team from the commissioned turbine supplier GHE is stretched to the limit here. "Our team has faced a number of challenges during the final assembly process. Primarily this involved the great logistical effort required due to the extensive equipment that is needed to get 15 turbines up and running at almost the same time. Another factor was the remoteness and difficult access to the valley, which meant that GHE demonstrated its flexibility again and again during the course of the project," explains GHE project manager, engineer Rainer P端hringer.

30 GWH OF CLEAN ELECTRICITY In total, the hydroelectric power specialist from Upper Austria is supplying 14 Francis turbines and one Pelton turbine for the six power plants in the cascade system. The gradients used, which extend over a length of around 15 kilometres, display differences in height of between 48 and 99.8 m. The power output data from the machines used is equally different: The output capacities of the turbines supplied by GHE are between 328 kW and 630 kW. The final mechanical assembly has now progressed to such an extent that the first start-up should be possible in just a few weeks. Ultimately, the intention is that the power plant cascade on the Uz should be fully up and running before the start of the summer. In a normal year, it will provide around 30 GWh of electricity produced from clean hydro power for the Szeker Land region. In any event, for the commissioned hydroelectric power specialists from Upper Austria, this once again demonstrates expertise in the emerging hydroelectric power market in Romania.


photo credits: zek

HYDRO

With foresight the builders of the Isenthal power plant had planned a largedimensioned powerhouse more than 60 years ago. This made it possible for the operators to install two additional machine units.

ADDITIONAL MACHINE UNITS FOR THE ISENTHAL POWER PLANT In the last few years Elektrizitätswerk Altdorf AG (EWA), energy supplier to the canton of Uri in Switzerland, has consistently expanded its own production capacities in the field of hydropower. One of the projects was the comprehensive refurbishment of the old Isenthal power plant during a low tide period in 2009. In the course of the 8.5 million francs project an additional new machine unit with an output of 2 MW was installed, which increased the total output of the plant by seven percent. In addition to this unit another high pressure turbine was installed last year in the powerhouse. The turbine uses the excess water of the drinking water source of the Seedorf municipality to produce about 1.2 million kWh of electricity annually.

photo credits: zek

cessed there in a powerhouse. The idea behind this strategy - to efficiently produce electricity for the winter - was great,” says diploma engineer Werner Jauch, board member and head of the energy division of EWA. “However, Lake Seeli in Seelisberg was not suitable as a storage lake as it could not be sealed off. A new solution had to be found which eventually led to the realization of the powerhouse at Seedorf.”

The building of the powerhouse of the Isenthal power plant is situated on the idyllic shores of Lake Urnersee.

INSPECTIONS FOR THE LARGE MACHINE UNIT The plant uses water from the Isenthalerbach Creek and from another creek. The water is stored in the Isenthal reservoir at 750 meters above sea level with a capacity of 21,000 m³. The water flows down a head of 320 meters through a 1,800 meters long pressure gallery and a 750 meters long penstock to the main building of the powerhouse, which has been

The Isenthal reservoir at about 750 m above sea level.

photo credits: EWA

I

t took an incredible half-century from the planning of the Isenthal power plant to the official launch in the mid-1950s. A record breaking planning period for a small alpine hydropower plant, which had originally been designed for a different strategy. “The plan at the beginning was to pipe water from Isenthal to Seelisberg. The water should have been stored in Lake Seeli – a natural lake -, piped through a penstock to Bauen and pro-

April 2013

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HYDRO

IDEAL SOLUTION FOR LOW TIDE PERIODS At this point the commissioning works of the brand new machine unit 2 were still in progress, which was intended in the new power plant concept to serve as a valuable addition to the existing unit. As Mr. Jauch put it: “Especially in times of low tide, in winter, when inspections were made, water was passing downstream unused since only one generator was installed between the two twin turbines. For this reason we made variant studies with the aim to build an additional unit into the powerhouse.” The building offered enough space to install a vertical machine unit. Judging by the large dimension of the powerhouse the builders must have taken into account such an eventuality. However, the operator had to face the issue of connecting the new turbine to the existing penstock. “The process water supply to the new turbine had to be connected to both intersections of the penstock system for technical reasons. We had to find a solution for this exacting situation in order to avoid one of the twin system turbines being impacted unilaterally,” Mr. Jauch explains. EFFICIENT COMBINATION OF MACHINES One important aspect of refurbishing is choosing the ideal machines. The operator EWA decided on a Pelton turbine with four injectors manufactured by Andritz. The runner, which was designed and manufactured by Jonschwil-based Turbal, has an output of 2 MW. The turbine drives a brushless synchronous generator manufactured by the German company AEM Dessau with a nominal rotation speed of 1,000 rpm. The combination of these machines guarantees an efficient energy production, a long life expectancy and a high availability. These were also the main aspects why the experienced hydropower specialists from the canton of Uri decided on this combination. ELECTRICITY FROM EXCESS WATER However, these were not the only machine units to be integrated in the Isenthal power plant. Only two years after the installation of the second

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The new machine unit 2: a Pelton turbine with 4 injectors, manufactured by Andritz Hydro, drives a directly linked synchronous generator by AEM. The turbine has an output of 2 MW.

photo credits: zek

erected in the idyllic scenery on the shores of Lake Urnersee. A twin-jet Pelton turbine with an output of 5 MW each was installed in the interior of the powerhouse to drive a generator placed between the two runners. “In order to be able to update the power plant's technology we had to shut it down for the refurbishment works in January 2009 until the next snowmelt,” says Werner Jauch. Within these three months the twin turbine and the synchronous generator were completely modernized. Also the switchgear and the transformers were refurbished. At the end of March machine unit 1 was put into operation again.

unit, in the winter of 2010/2011, another high pressure multi-jet turbine with a vertical shaft was set up: the Seedorf power plant. The process water comes from the drinking water system of the Seedorf municipality. “The results of the measurements we took beforehand showed the exceptionally high discharge capacity of the Chuchibach Creek. It seemed a reasonable option to use all excess water which would not be needed for the drinking water supply of the region as an energy source,” Werner Jauch recalls the early stages of the project. After the residents of Seedorf gave approval to the project, EWA along with the municipality of Seedorf founded KW Seedorf AG and immediately set about the project development. Various different power plant strategies were examined and eventually the machine units were installed in the main building of the Isenthal power plant at the same sea level as Lake Urnersee. Hence it is not a drinking water plant in the traditional sense. Drinking water is deducted halfway and only excess water is directed to the new machine unit through the penstock.


Technical Data: Gross Head: 327 m Turbines: Twin-jet Pelton Turbine Generator: Synchronous Generator

w w

Output: 5 MW each Nominal Output: 12 MVA

Machine Unit 1

w w w w

Gross Head: 327 m Turbines: Pelton Turbine with 4 nozzles Manufacturer: Andritz HYDRO Generator: Synchronous Generator

w w w

Output: 1935 kW Nominal Rotat. Speed: 1,000 rpm Nominal Output: 2,100 kVA

Machine Unit 2

Isenthal Power Plant: w w w

w

Average Energy Capacity: approx. 45 GWh

w w w w w

Flow Rate: 148 l/s Turbine: Pelton Turbine with 3 nozzles Manufacturer: Sigrist Generator: Asynchronous Generator Average Energy Capacity: approx. 1.2 GWh

w w w w

Net Head: 320 m Output: 409 kW Nominal Rotat. Speed: 1,500 rpm Nominal Output: 480 kVA

photo credits: zek

HYDRO

Seedorf Power Plant:

COMPACT POWER UNIT FROM CENTRAL SWITZERLAND The head from the Chuchibach equalizing reservoir to the Isenthal powerhouse is 363.5 meters. The machine unit was designed for a flow rate of 148 l/s. It consists of a vertical axis Pelton turbine with three injectors manufactured by Sigrist AG and a directly linked asynchronous generator. What instantly catches the eye is its unusual compact design, which is a relevant advantage considering that with the installation of machine unit 2 the space in the powerhouse was limited. The new machine unit using the excess water of the Chuchibach Creek has been in operation since June 2011. The plant produces electricity for about 240 households. The efficiency of the plant now proves that the residents of Seedorf were correct about confiding in the plant by voting with a clear majority for the construction. Due to the great know-how of EWA the plant was realized without any complications. Naturally, EWA is now also cooperator of the plant.

Diploma engineer Werner Jauch, board member and head of the energy division of EWA, next to the machine unit of the new Seedorf power plant. A very compact Pelton turbine with 3 injectors was installed to process the excess drinking water of the municipality of Seedorf. The turbine by Sigrist AG produces an output of 409 kW.

nology. Mr. Jauch says: “Today our key competencies lie in the planning and programming of control systems. For this, we can rely on experience from our own plants.” And it pays off with each new power plant project.

100 PERCENT SELF-SUFFICIENT At the moment EWA runs 11 hydropower plants, which produce about 220 GWh of electricity for the canton of Uri. Hydropower is and will remain the most important electricity source for the canton famous for the legend of William Tell. According to the Isenthal concession EWA is obliged to guarantee a sufficient, steady and reasonably priced electricity supply to the canton of Uri. At the moment the output of Uri's most important energy supplier offers a degree of self-sufficiency of 75 percent. This figure, however, is still to be increased. “Our goal is to reach a degree of self-sufficiency of 100 percent and expand our capacities even further. With the projects planned in the canton of Uri we will expand our capacities by about 150 GWh within the next few years. We are currently working on the realization of our most important projects,” says Werner Jauch. The successful expansion of the powerhouse of the Isenthal power plant represents the energy supplier's consequent strategy to increase the offer of green electricity in Uri step by step. An expansion in the fields of hydropower definitely plays a key role in this context. A COMPETENCE CENTER IN THE SAME BUILDING A trademark of EWA is its own local hydropower competence center. This enables EWA to offer all kinds of services, including project development, variant studies, authorization procedures, commissioning, maintenance, controlling as well as electricity and certificate trading. These services are available for third parties as well, especially to clients with smaller or medium-sized hydropower plants. The supplier of the canton of Uri has a highly-qualified team, which has gained a lot of experience in many fields, including control tech-

Made in Germany

-Anhaltische Elektromotorenwerk Dessau GmbH

www.aemdessau.de

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photo: zek

HYDRO

The power house and weir gate of the new Schaldorf power station. Thanks to careful management by evn naturkraft, the locals and neighbouring residential area in the background were spared negative interferences of the construction work.

EVN COMPLETES MODEL PROJECT IN SENSITIVE AREA OF MÜRZ RIVER It was already in the late 1970s that Schaldorf in the Styrian community of St Marein was rated as suitable for future hydropower projects in a potential evaluation study. Around 30 years later, hydropower specialist evn naturkraft went ahead and launched this bold project in the sensitive area between the Trieb and Mürzhofen power plants. Within an extremely short time, they implemented a veritable model project, both in terms of hydropower engineering and ecological compatibility.

VALUABLE OLD ALLUVIAL LAND ACQUIRED The operators took this sustainable approach not just with respect to the people of the region, but applied the same principles to the

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ecological requirements of the area where the new power plant was to be built. As a result, 3.2 hectares of alluvial forest were purchased and put out of commercial use. A dosing system now carries the annual flood flows towards the alluvial forest to help preserve the old woodland plot in its pristine state. Where ecological planning is concerned, evn relied on a collaboration with renowned river engineering expert Otmar Grober, who is known for his innovative approach to near-natural waterway development.

IMPROVED WATER STORAGE The plans for the Schaldorf power plant called for a water storage space that should adapt as much as possible to the natural flow of the river. This is where the specially constructed, submerged groynes came in, which Otmar Grober had developed at the regional building directorate of Bruck an der Mur. These induce spiralling currents at the bottom of the river to ensure selectively dynamised flow rates. As Martin Scharsching explains, “These submerged groynes help to clear away the dregs photo: zek

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hen they are asked about hydropower construction in their area, the locals in the Styrian municipality of St Marein have a lot of positive things to say. This is not just the result of the marvellous opening ceremony for the new power station in late July, which operator evn naturkraft organised at the town’s sports grounds, with a free buffet as a token of gratitude to the community. Rather, from the time when construction work began in February 2011, the contractors had made it a priority to avoid as much as possible any interference with the quality of life of the nearby residents. For this reason they set up a separate motorway slip road. Martin Scharsching, DI, explains its purpose by saying, “With the slip road in place, we were able to transport material to and from the construction site directly via the motorway, sparing the local residents all the noise and dust. Our cooperation with the motorway operator, Asfinag, went very well. The road was in place for about a year and was then removed again.”

The storage are of the Schaldorf power plant, and neighbouring plot of alluvial forest, which was purchased and put out of commercial use by the operators.


photo: zek

The influx of the river water generates a potential vortex in the activation basin.

photo: zek

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Martin Scharsching, DI (l.) and Otmar Grober, about to put the FAH activation basin into operation.

within the storage area when the water level is high, and at normal water levels they prevent sediment from settling within their reach. This leaves the coarser, looser bottom substrate, which improves the ecological conditions for fish in the storage area quite a bit.” Adds Otmar Grober, “The advantage that this particular arrangement has against many other facilities is that the bottom level of the weir is only around a metre above the bottom level of the old River Mürz. This makes it easier for us to create dynamic conditions with the groynes within the storage area. In scenarios where the elevation of the weir is high above the bottom level, this can lead to problems due to the shearing stress, and then even groynes are useless.” The selected elevation of the weir has the added benefit of limiting the length of the storage area, which eliminates the possibility of interference with the Mürzhofen power station around 3 km further up the river.

the bottom of the basin another bypass leads directly into the first reservoir of the fish pass at the intake on the tailwater side. The ‘sucking’ opening at the bottom of the activation basin creates a swirling motion in the river water that is fed into the circular reservoir. This is to cause the water to receive an electrical charge as it moves past the silicate containing reservoir wall in a rotational flowing motion. When ‘activated’ in this manner, the river water is supposed to improve the quality of the attraction flow water at the intake of the fish pass which, as Otmar Grober believes, is essential for the fish to find the fish pass in the first place. A fish pass based on the same activation principle has already been installed at the evn power station at the River Salza. There, local fishermen had to give up their favourite spots near the weir pothole, as too many of the graylings and brown trouts preferred the new fishway to the actual river.

SIMPLE, COMPACT POWER HOUSE The hydropower facilities as a whole blend unobtrusively yet confidently into the surrounding landscape. According to project manager Martin Scharching, the main focus during construction was on functionailty, with a view to minimising future maintenance efforts: “The power house was designed so that, during the various stages of completion of the power house, the turbine components and generators could be transported directly into the building with a flatbed truck, hauled off the vehicle and installed straight away. If, decades from now, the machine need reconditioning, they can be removed and transported away quite easily with an indoor crane and flatbed truck.” Following the completion of the power house, the single-step installation of the turbine (i.e., installation without interfering with the building construction) was one of the reasons why the

COMBINED FISH PASS AND ACTIVATION BASIN A fish pass in the form of a classic slot pass was installed as part of the project. At the half-way point, it leads into a generously spaced, near-natural basin pass, which also serves as a natural habitat in its own right for fish, invertebrates and amphibians. The outlet was installed with exemplary perfection, i.e., as far away from the weir as possible. When they installed the fish pass, the engineers were able to apply one of Otmar Grober’s ingenious innovations to optimise the attraction flow. Water is carried from the storage area via the bypass into a circular shaped activation basin, the walls of which are coated with silicate-based magnesite. From April 2013

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illustration: Jank

With project manager Martin Scharschnig’s two daughters acting as patron saints for the turbines at the opening ceremony, the two machine units were christened “Johanna” and “Theresa” before they were started up for the first time.

photo: evn

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The turbines’ vertical architecture with the directly coupled synchronous generators makes the machines particularly maintenance friendly.

contractors were able to complete the entire plant facilities without problems and within a very short time. TWIN-SET OF GENERATORS IN A MAINTENANCE-FRIENDLY DESIGN The above-mentioned core element of the new hydropower plant is a machine combination that previous installations have shown to be a ‘match made in hydropower heaven.’ The two structurally identical, double-regulated Kaplan turbines by Upper Austrian family-owned manufacturer Jank, each combined with a direct coupled synchronous generator by Koncar, generate an overall annual total of 5.4 million kWh. With a flow rate of 14 m3/s per turbine and installed overall output of 1.15 megawatts, the plant will supply 1,500 households in St Marein and the surrounding region with local eco-power. For the Schaldorf plant, a specially refined turbine design was chosen, which is particularly optimised for use in twin-machine arrangements. As a result, the two machines work at a high level of efficiency both under full load and when the drop head is lowered due to floods. The decision to go with a vertical alignment for the two turbines was also influenced by considerations of maintenance friendliness, as DI Scharsching confirms: “The reason we went for vertical Kaplan turbines was that this allows staff to access the entire mechanism by way of a shaft. We were also careful to avoid the need for gearings. At the end of the day, we are very happy with the solution that Jank and Koncar

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have implemented – everything is working perfectly. One thing I should mention particularly is the low noise level of the generators: they operate with very little vibration and very quietly.” Also, the vertical design makes the turbine arrangement more cost efficient than an alternative arrangement with bulb turbines. REGIONAL TOUCH PROMOTES IDENTIFICATION WITH THE PROJECT The fully automated control of the facility was implemented by Schubert Elektroanlagen. Haider of Kapfenberg (Styria) was responsible for the extensive earth works, concrete placement was contracted out separately to Leyrer + Graf. The contract for the extensive hydraulic steelwork installation went to specialist Mayrhofer of Wenigzell (also Styria). They supplied and installed the weir baffle, the buttomoutlet drain valve with flushing gate, as well as two intake valves, the horizontal fine-screen trash rack with 30 mm bar spacing, and a modular stop log system. Also the hydraulic system for the entire hydraulic steelwork was installed by Mayrhofer. Construction planning and on-site supervision was carried out by the offices of Mach & Partner ZT GmbH of Judendorf (Styria). This choice of local firms aptly reflects the overall local character of the entire project. This means that in additiom to the plant generating electricity for users in the immediate environment, the operator’s choice of contractors also


On-site trial installation of the trurbine sets

ensured that most of the value generated by the plant remains within the region as well. This was another aspect of the project that found favourable reception with the local Mürztal citizenry. Meanwhile, operator evn is already focussing on the next generation of local citizens: when 2,000 trees and 14,000 shrubs were planted in the surrounding area of the plant’s premises, the pupils from the local schools of St Marein and Allerheiligen were invited to join in, which allowed them to learn first-hand about ecological aspects and the way a hydropower plant works.

Technical characteristics w

Design flow rate: 28 m3/s

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Gross head: 6 m

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Turbines: Vertical Kaplan (2 units)

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Manufacturer: Jank

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Flow capacity: 1,15 MW (total)

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Generators: Synchronous (2 units)

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Manufacturer: Koncar

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Nominal rotational speed: 200 rpm

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Rated output: 750 kVA

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Standard capacity: approx. 5,4 GWh

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Control: Schubert Elektroanlagen

OPEN-AIR CLASSROOM FOR THE NEXT GENERATION At the start of the current school year, the project contractors are set to take a further step in supporting the local youth and promoting their understanding of the connections between various aspects of nature and responsible energy production: in the area of the purcased alluvial forest plot, they are planning to open an outdoor classroom for the students of the surrounding schools. In making Project Schaldorf a reality, evn naturkraft contributed know-how gained

photo: zek

photo: Jank

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The fully automated control unit

from new constructions and revitalisation projects of recent years, as well as the extensive experience as an operator of around 70 hydropower facilities. “We have been granted water rights until the year 2100,” says project manager Martin Scharsching. “It makes you think about the vast responsibility for the entire region that you are taking on for this long period of time.” Their model power plant stands as living proof that the project contractors are more than able to live up to the responsibility.

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37-TON POWER UNITS HEAVED INTO SOHLSTUFE LEHEN POWER PLANT

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he realization of the Sohlstufe Lehen power plant, which now enters its final constructing stage, is one of the most exciting and interesting power plant projects in Austria. The biggest part of the construction works has been completed and the mechanical engineers are set to equip the power plant with the electromechanical components. On Thursday, March 07, 2013, the heavy load transporters arrived at the construction site, delivering the synchronous generators, which will soon transform the mechanical energy of the turbines into electricity.

The first machine unit component on its way into the “body” of the power plant: The synchronous generator with a weight of 37 tons is being heaved carefully into the plant.

photo credits: Salzburg AG

The Sohlstufe Lehen power plant, a run-of-the-river power plant in the northern part of the city of Salzburg, is to be commissioned soon. The two generators with a weight of 37 tons are the core pieces of the new plant. They were brought to the site in a heavy load transport and lifted into the powerhouse on March 7, 2013. They are scheduled to be installed within the next few weeks, together with the turbines, which will arrive soon. The power unit of the plant will be launched in mid-2013 and will produce about 81 million kWh of clean electricity in a year on average.

The heavy load of 37.3 tons was supplied by renowned Austrian manufacturer ELIN Motoren GmbH, based in Preding/Weiz. The three-phase synchronous generators run with a nominal rotation speed of 600 rpm and have a nominal output of 9,000 kVA each. Quality ELIN Motoren generators stand for top degrees of efficiency and a robust design, which guarantees high availabi-

photo credits: Salzburg AG

The synchronous generator by ELIN Motoren has reached its final destination. Both generators will be installed together with the turbines within the next few weeks.

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lity. The generators are to be installed together with the turbines within the next few weeks and should be operating by midyear. CLEAN ELECTRICITY FOR 23,000 HOUSEHOLDS IN SALZBURG The machine units are designed for a design flow of 125 m³/s. In total, the two Kaplan turbines, when operating at full capacity, will process 250 m³/s of water from the Salzach River. The runners are dimensioned accordingly, with a diameter of four meters. Their nominal rotation speed is 115 rpm, which is transformed into 600 rpm of generator rotation speed by the interconnected spur gear unit. With a head of 6.60 meters the two turbines have a bottleneck capacity of 13.7 MW. With this output the newest power plant of Salzburg AG company will produce 81 million kWh of clean electricity per year on average, sufficient for 23,000 households in the northern part of Salzburg.

SYNERGY OF RIVER ENGINEERING MEASURES AND ENERGY PRODUCTION From the beginning, producing energy has not been the only focus of the project, although the convincing capacity figures may suggest otherwise. The construction of the power plant, which is close to being finalized, brings additional benefits, which is why the


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photo credits: Salzburg AG

The new Sohlstufe Lehen power plant helps prevent the increasing bed degradation of the Salzach River. As planned, the power plant will be put into operation this summer.

plant has experienced a huge support by the residents of Salzburg. Firstly, the flood control is improved through the project's various accompanying measures. Secondly, the groundwater situation in Salzburg is stabilized. Thirdly, as one of the most important aspects of this project, the power plant helps prevent the increasing bed degradation of the Salzach River. The comprehensive river engineering measures along with the production of clean, green electricity form a synergetic unit. The representatives of the project attached importance to meeting a high ecological standard with the plant right from the start. A passage for fish at the existing vertical hard basin drop structure will be installed, a flood discharge flume will be recultivated and riparian forests will be reforested - to name only a few ecological measures. Furthermore the new design of the surrounding Glanspitz natural area influenced the shape of the project. Currently a local recreational area is being built with foot-

paths and bike trails for the residents of Salzburg, whose many ideas helped in the creation. There are plans for playgrounds and resting spots and an expansion of sports and spare time facilities is being elaborated as well.

Another great achievement is the architectural design of the weir by architects Erich Wagner and Max Rieder. Salzburg AG has set a sign for the development of the city by combining a whole range of various additional benefits in one plant – more than any other hydropower plant in Austria.

A SIGN FOR THE DEVELOPMENT OF THE CITY The energy supplier of the province of Salzburg is investing no less than 85 million euros in the project of the Sohlstufe Lehen power plant. The construction works began in the summer of 2010 and are now close to being completed. The project involved the local residents to a large extent. The focus of all participating parties lay on the development of the construction site, which resulted in directing the biggest part of the heavy load traffic through an individual highway access. The constructive dialogue with the residents of Salzburg played a key role in the successful construction of a hydropower plant of this size in an Austrian provincial capital.

Leading global supplier of electric motors up to 35 MW and generators in the power range up to 50 MVA.

Technical Data: w

Flow Rate: 2×125 m³/s

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Gross Head: 6.60 m

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Bottleneck Capacity: 13.7 MW

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Turbines: 2 Kaplan Turbines

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Manufacturer: Voith

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Turbine Rotation Speed: 115 rpm

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Generator: Synchronous Generator

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Manufacturer: ELIN Motoren GmbH

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Generator Rotation Speed: 600 rpm

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Generator Output: 9,000 kVA each

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Nominal Voltage: 6.3 kV

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Average Energy Capacity: approx. 81 GWh

ELIN Motoren GmbH Elin-Motoren-Straße 1 A-8160 Preding/Weiz Tel. +43 3172 90 606-0

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photo credits: Green Energy City

Along with the power station in Lempdes-sur-Allagnon, there are already the two plants in La Chapelle and Villognon in the fund which Green Energy City is offering for investment.

GREEN CITY ENERGY ENABLES PARTICIPATION IN SMALL FRENCH HYDROELECTRIC POWER STATIONS Green City Energy was founded in 2005 as a 100% subsidiary of the largest Munich environmental protection society Green City e.V. From the beginning, the official aim in its own words was to support a decentralised and democratic energy revolution owned by the citizens. In practical terms, this means: The company plans renewable energy power plants in the fields of wind energy, hydro power, and originally also solar energy. The projected plants are offered to small private investors in the form of investments in funds. For example, these include investment funds in small French hydroelectric power stations, which can be found recently in portfolios of offerings from the German energy service provider. zek HYDRO took the opportunity and contacted Jens M端hlhaus, CEO of Green City Energy, who willingly granted a look behind the scenes. How important is hydroelectric power for your company and what role can it play for the intended energy revolution? M端hlhaus: Hydroelectric power is, in any event, an important base for change in energy production. At the moment, hydroelectric energy represents about 3% of the German energy mix. This doesn't sound like very much at first glance, and hydroelectric power is already widely developed, particularly in the south of Germany. However, a study commissioned by the BMU (German Ministry for the Environment) estimates the total potential for hydroelectric power in Germany to be between 33.2 and 42.1 terawatthours, so there are still many opportunities, especially in the area of modernisation. And hydroelectric power has other advantages. As is the case with wind energy, hydroelectric power is already produced much nearer to the market price than solar energy, leaving a relatively smaller target for political criticism. With proper maintenance, the technology has an extremely long service life; a hydroelectric power station can easily produce green electricity for 60 to 90 years. With hydroelectric power, we also have very high availability of more than 90%, and with pumped storage power plants, for example, flexible operation as well. In this way, renewable energy can be stored.

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Green City Energy has been actively involved in hydroelectric power since 2006. Together with the Munich utilities company, we planned and commissioned the sophisticated underground Prater power station in the middle of Munich. This, of course, enabled us to gain invaluable experience. Amongst other things, we are engaged in the modernisation of existing small hydroelectric power stations in France. This is particularly valuable from an ecological perspective, as this renders the construction of new dams unnecessary. This is an improvement from both ecological and economic points of view. The modernised or revitalised plants are currently offered to the public for financial participation in the "Wasserkraft Frankreich" fund. What significance does the Prater power station in Munich have for the development of the company? And what were key lessons learned from this project? M端hlhaus: Certainly, the project laid the foundation for the expansion of our services to include hydroelectric power; in that way, it was very important for Green City Energy. Even today, there is still great interest in the power station, which pleases us immensely. Of course, planning in the


middle of a city was not exactly easy. The worries of the residents about a possible change in the urban landscape had to be taken into account, and there were unexpected delays which, in our case, were caused by flooding in 2009, partially washing away the riverbank. However, such a project is exciting even without incidents: Before the underground construction work could begin at all, the area had to be pumped dry and the fish removed by hand; for this around 200 employees of the fisheries authority were in action and a total of 60,000 pumping hours were necessary. Now, there is a pressure pipe 150m long and 4.5 wide in the bed of the river Isar. 600 bored piles with a length of up to 10m each were installed, and a total of 3,500m続 of reinforced concrete and 800t of reinforcement steel were used. The power station chamber is a full 25m below the riverbank. The Kaplan turbine with a diameter of 230 cm was developed specially for the location and combines advanced technology from wind and water power. A gearless ring generator from Enercon allows continuous regulation and thus optimal energy production. In 2012, the Prater power station yielded some 20% above forecast. Your company relies on communal participation models in the field of wind energy and, now, investment funds in small French hydroelectric power stations are being offered in the hydroelectric power sector. Which strategy are you following with these models? M端hlhaus: Basically, we support a democratic energy revolution from the bottom up. We achieve this by financing the plants through citizen participation funds. In this way, the plants belong to the investors, who also profit from the yields. A representative study by TNS Infratest in 2011 showed that citizens identify with the plant in their neighbourhood because of its proximity and the possibility of financial interest in an eco-power plant, which increases its acceptance. In this survey, 69% of those people questioned who lived near to a wind farm were in favour of wind farms in the immediate neighbourhood. This is also true for other types of renewable energy plants. The planning of local renewable energy plants also provides communities with good opportunity, on the one hand, to achieve their own energy independence and, on the other, to increase value. Since 2008, we have also been offering active support for local authorities on the way to local energy independence together with our communal energy consulting This includes extensive analyses of potentials and an individual action-oriented timetable for local energy independence and increases in value.

Apart from the Prater power station in Munich, you now operate hydroelectric power stations in France. What makes small French hydroelectric power stations particularly attractive to investors, and where do you see differences to hydroelectric power stations in Germany in this respect? M端hlhaus: We were introduced to this market through our branch in Toulouse. First, hydroelectric power has a long tradition in France as the only renewable source of energy and a good standing; around 12% of the French energy requirement is covered, which is otherwise dominated by nuclear energy. In addition to the large plants, there are some 1,700 small hydroelectric power stations, which are mostly privately owned. However, many of these power stations have been operating a long time. Most of the technology used cannot fully utilise the potential of the location. To solve the congestion, the French government promotes modernised power stations by way of a fixed remuneration, similar to the feed-in tariff in Germany. Some owners cannot or do not wish to finance the necessary modernisation work and therefore sell their power stations. We modernise them in accordance with ecological standards, which increases their efficiency, and offer the investors high security due to the fixed remuneration. In Germany, we are currently exploring the market. Hydroelectric power in Germany is already quite developed, particularly in the south of the country. However, we are generally very interested in acquiring power stations or water rights here as well, in order to create similar funds in Germany. The operators of power stations often mention the responsibility to people and the environment connected with the acquisition of longterm water rights for a hydroelectric power station. How do you view your responsibility for the projects in France? M端hlhaus: As the subsidiary of an environmental protection society, an ecologically correct implementation of our projects is very important to us. With the hydroelectricity fund in France, we are already revitalising small hydroelectric power stations, which means that not only the approval risk for the investor is very small but also that, above all, it is unnecessary to construct new dams. In this way, there is no further intervention in the ecology of the fresh water. In addition, the subsidies are linked with clear requirements which also include the optimisation of the ecological aspects of the power station. This suits our objectives. For example, close-toothed combs are installed to protect fish, and new fish ladders enable the fish to ascend and descend easily. The turbines we use for the modernisation have advanced and photo credits: Green Energy City

The Kaplan turbine with a diameter of 230 cm was designed and manufactured specially for the Prater power station in Munich.

photo credits: Green Energy City

Foto: Troyer

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The machinery of the Prater power station rotates at 25m below ground level.

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proven technology from professional manufacturers, generating the best possible yield for the particular location. In this way, we can improve the existing resources and fully utilise the potential without causing serious disruption to the local environment. After completion of the modernisation work, we do not give up responsibility for the plant. Our French branch Green City Energy France in Toulouse remains on site managing the operating companies. By continuous reporting to Green City Energy AG, support can be provided from Munich with technical issues and with the administration of the plant. The control of the operational management is also carried out from here following the principle of dual control.

The hydroelectric power stations in France are renovated to the most modern criteria and brought up to date.

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photo credits: Green Energy City

How many power stations have already been included in the French investment fund and what are the criteria used in the selection of these small power stations? M端hlhaus: In the meantime, three locations in Lempdes-sur-Allagnon, La Chapelle and Villognon are included in the fund; three further power stations are currently undergoing due diligence processes and there are more in the pipeline. There are concrete and irrevocable investment criteria; compliance with these is reviewed by an investment committee for each acquisition. Before acquisition, the hydroelectric power stations or the hydroelectric power companies owning them are subjected to technical, economic and legal analysis by specialists, tax consultants and lawyers, with the analyses being available before acquisition and forming the basis for consent and release. Basically, they must be small 0.4 - 2 MW power stations in need of renovation or modernisation, which, after upgrading by prescribed investment in accordance with French law, get a 20-year feed-in tariff. Whether or not the modernisation has been completed before acquisition or completed afterwards does not matter. Additionally existing power stations, for which the fixed tariff is expiring, can be purchased into the funds, if the costs of production of electricity are at market level. In this case, the electricity produced is sold on the open market through the energy exchange without feed-in tariff. A regional and technical diversification is also important in order to increase the security of income for the investors. The purchase price of a plant, including planned modernisation costs, should be no more than 11 times the forecast of the future annual net income.

photo credits: Green Energy City

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With the sensational Prater power station in Munich, Green City Energy took the first step in the hydroelectric energy market.

What expertise does Green City Energy bring directly into the project process; in which areas are partnerships or cooperations entered into? M端hlhaus: First, through its own French branch, Green City Energy naturally provides the necessary commercial know-how, knowledge of the French renewable energy market and the appropriate contacts. Therefore, the main responsibility for the selection and investigation of hydroelectric companies to be acquired is ours; in addition, we support the technical due diligence investigations and accompany contract negotiations. Incidentally, the costs of unsuccessful acquisition attempts are borne by us. Due to our many years of experience, we also have a wide ranging network of competent local planners, engineers and technicians. This is, of course, also put to good use in the individual steps, such as acquisition, project investigations, purchasing preparations, modernisation, operational management and maintenance. Green City Energy AG then assumes the commercial management for GCE Wasserkraft Invest Frankreich GmbH; the administration of the hydroelectric power companies is carried out by our French company Green City Energy France S.a.r.l. What possibilities do you offer your investors to request detailed information about the technical condition and the energy-economic potential of the modernised plants in France? M端hlhaus: We highly value transparency and are always ready to speak personally with our investors and interested parties. Our colleagues in investor relations are available to answer questions by telephone or email. Basic information is, of course, available on our web site, where anyone can download the detailed sales prospect approved by BaFin (the Federal Financial Supervisory Authority) and audited by IDW S4. If requested, the prospect can also be sent by mail. In addition, the web site regularly records the progress of the structuring of the fund and the individual progress of projects in Fact Sheets. During the emission, the experts are also available at


detailed information events for specific queries. After completion of the placing of the fund, there are annual shareholders' meetings, in which the management presents the financial statement figures and the annual dividend is decided. In addition, at the first shareholders' meeting, a three-member advisory board is elected from the ranks of investors. This henceforth serves as a supervisory body and intermediary between the investors and the management, and at the annual shareholders' meetings reports on its independent review of the fund documentation. In addition, the investors are informed of the yields and the status of projects via our password protected investors portal.

The German energy service provider is currently looking for more hydroelectric power stations in France, Italy, Germany, Austria and Switzerland.

photo credits: Green Energy City

What yield prospects do you offer your investors in your hydroelectric power fund and on what parameters are these calculated? What general advantages do the investors see in your hydro-electric power fund? Mühlhaus: The forecasted average payout of the French hydroelectric power fund is 8.35% annually. For the annual net income calculation for plants to be renovated or which have recently been renovated, the average water values of the last ten years are multiplied with current electricity prices. The assumptions are supported by technical assessments from independent engineering consultants and by earnings guarantees laid down in the purchase contracts with the technical manufacturers. Further security is also offered in this case by the feed-in remuneration, legally guaranteed by the French government for 20 years, for small modernised hydroelectric power stations. In the event of the acquisition of plants not needing renovation, the average yields actually produced over the last ten years and technical experts' reports are used. There are many advantages of participating in this fund. First, it is a pure equity fund without bank financing and with a relatively short term of just eight years and good earning opportunities. In addition, the investor is investing in ecological material assets with a real value. As the power stations already exist, there are no risks with building approvals or construction. The three-stage construction of the fund is clear and offers the opportunity of nearly tax-free dividends, the applicable capital gains tax is a maximum of 25%. The fixed investment criteria and the standardised due diligence investigations ensure a stable project portfolio. Furthermore, the state-guaranteed feed-in remuneration offers additional security, and the entry prices on the French market are currently low. Green City Energy also offers a buy-back guarantee at a guaranteed purchase price of 15 times the annual net income, plus a 50% more income guarantee.

photo credits: Green Energy City

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With the renovation, great attention is placed on an ecological enhancement; fish passability is very important in every case.

How would you assess the risks for an investor in your investment fund in direct sales? Mühlhaus: The sales prospect is approved by BaFin and audited by IDW S4, which means that the fund concept has undergone extensive economic reviews, offering our investors additional security. A possible risk of direct selling remains in that we inform the investors only of the details of the fund; we do not offer investment advice for making an investment decision. However, for those to whom this is important, this does not mean that one cannot invest. Those interested can obtain advice about the Hydro-electric Fund France from a few select independent investment advisers. Are you planning to expand your hydroelectric business to other countries in the future? In this respect, which international markets would you class as being of interest? Mühlhaus: Apart from further plants in France, we are actually looking for hydroelectric power stations to buy or lease in Germany, Austria, Italy and Switzerland. Water rights are also of interest to us. If the offer is available, we are planning various communal participation models here too.

We are looking for hydroelectric power stations in German-speaking countries (D, A, CH), France and Italy. (also in need of renovation)

• For purchase • For rent

• Equity holdings • Water rights

For further information: Tel. +49 (0)89/890 668-158

photo credits: Green Energy City

wasserkraft@greencity-energy.de

Jens Mühlhaus, CEO of Green City Energy AG www.greencity-energy.com/searching-for-new-projects

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photo: zek

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Small-scale hydropower station at the River Mürz in the Austrian province of Styria

MAXIMUM YIELD AT MINIMAL COST - NEW THINKING IN SMALL-SCALE HYDROPOWER GENERATION by Univ. Prof. Dr.-Ing. Peter Pelz Dipl.-Ing. Manuel Metzler

At the Department of Fluid Systems Technology at the Technical University of Darmstadt, new concepts for optimising environmentally sound hydropower facilities are being developed under the direction of Univ. Prof. Dr.-Ing. Peter F. Pelz. The requirements imposed on hydropower generation by today’s Water Management and Environment Protection Acts call for solid, economically viable machine concepts.

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dolf Pfarr, who in 1897 was the first to assume the Chair of Fluid Systems Technology at the Technische Universität Darmstadt, was also the first to develop a controlled hydropower turbine. It was Pfarr’s designs that the trailblazing Voith turbine controller of 1879 was based on. Following in the footsteps of Adolf Pfarr, we specialise in pioneering new ideas when it comes to developing environmentally compatible turbine concepts with a high level of profitability. Where the long-term success of a technology in the energy sector is concerned, output-indexed investment costs are a crucial factor. The initial electricity production costs of small-scale hydropower stations are determined chiefly by the investment costs, with maintenance and operating costs typically ranging much lower in scale [Wissel et al., 2008]. Low output-indexed investment costs kp enable short amortisation times for power stations and ensure a high level of profitability in the long run. For this reason, lowering these investment costs is a focus of research at the Institute for Fluid Systems Technology.

IS EFFICIENCY A SUITABLE MEASURE FOR COMPARING HYDROPOWER STATIONS? To anticipate the answer to this question: no, it is not! In technology, as in public discourse, there are terms that are either used imprecisely or (e.g. for marketing reasons) misleadingly. “Energy efficiency” is one such term. For an unbiased discussion of the matter

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- which today concerns all areas of engineering - it is necessary to understand the path to energy efficiency as a two-stage process, which consists first and foremost in optimising the system, and secondarily in scaling up e.g. the efficiency level of individual system modules. Efficiency issues are always part of the scaling tasks of a module. A much more important issue - and therefore of higher priority - is the optimisation task of the system. For wind turbines Albert Betz already discovered in 1920 that the theoretical energy maximum that can be generated from any wind-powered machine is 16/27 of the total wind energy used. This means that even an ideal, lossless machine (with hydraulic efficiency η = 1) cannot transform more than 16/27 of the available amount of wind energy into mechanical power. Conversely, it is possible that an unfavourably set operating point of a machine with the hydraulic efficiency η = 1 may have a mechanical power output that is considerably below the 16/27 mark. Most studies on the topic of energy efficiency for hydropower installations focus on the hydraulic efficiency η of the machine as an overall quality criterion for the hydropower station. This is usually defined as the ratio of the mechanical power PT = MΩ (M: torque; Ω: angular frequency) of the machine to its hydraulic power output PH = ρgHT (HT: turbine head, Q: volume flow rate) of the volume flow passing through the machine.

However, all the hydraulic power ratio tells us about the machine is which fraction of the hydraulic power the machine is capable of gene-


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rating at the selected operating point. The question one must ask oneself when it comes to optimising the system is this: at which operating point does the ratio of the available energy transformed into mechanical power attain its maximum (i.e., optimum)? This ratio is described by the coefficient of performance (or “yield factor”)

To highlight the difference between the hydraulic output efficiency and the performance coefficient, Figure 1 indicates the measurements of these factors in an undershot waterwheel by M. Troger [Troger, 2008], plotted above the dimensionless volume flow and the (also dimensionless) tailwater level. These factors, which we shall deal with in more detail in the next section, describe the system’s operating point. However, the following is already obvious from the graphs: the red arrows mark the maximum levels of hydraulic output efficiency (left graph) and performance coefficient (right graph). At the point where the performance coefficient attains its maximum (Cp = 0.315), the hydraulic output efficiency is η ≈ 0.85, i. e., around 15 per cent below the optimum hydraulic output efficiency of η = 0.999. Yet, the energy yield at maximum performance is higher by a factor of around 2.

model as it stands are independent of the type of machine being considered. The “effective height” is defined as

Figure 2: Optimum operating conditions for small-scale hydropower

Here ∅z describes the topological difference in elevation between the headwater and tailwater, h1 represents the water level, and u1 stands for the flow velocity at the headwater. The available energy can be determined, by applying Betz’ thought experiment with a hypothetical, ideal machine, as

The difference between this case and the optimisation task addressed by Betz is that the hydropower case requires that we have to include gravitation as an additional parameter in our optimisation equation.

Figure 1: Hydraulic power output and performance coefficient of an undershot waterwheel, according to measurements by Troger

Our conclusions, viz. (i) that the hydraulic output efficiency is not an appropriate measure for comparing small-scale hydropower stations, and (ii) that the performance coefficient depends on the operating condition of the system, lead to the following question:

WHAT IS THE OPTIMUM OPERATING POINT OF THE HEADWATER – MACHINE – TAILWATER SYSTEM? For hydropower stations, the system to be optimised consists of the three components of headwater, machine, and tailwater. The optimisation objective consists in determining the operating point where the possible maximum of mechanical power output is generated from the available energy. For this purpose, Pelz took a fundamental view on the headwater-machine-tailwater system [Pelz, 2011], which is illustrated in Figure 2. Let us consider a channel with rectangular cross-section and width b. As with Betz, the conclusions that can be drawn from the April 2013

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Given the specific volume flow rate q2 = Q/b (volume flow Q, water level at tailwater h2), we may express the mechanical power output PT as a function over h2 and q2:

the red dwarfs at the main sequence, then proceeding to stars like our sun and beyond.

Scaling for the available power, we get the performance coefficient, whose maximum we can calculate analytically as Cp,opt = 0.5. In words, this means that in an open channel flow at most half of the available energy can be converted into mechanical power. Furthermore, it is possible to derive the optimum operating point, i. e., the optimum volume flow rate and head, for a given energy supply. The result of doing so shows that the optimum operating state is achieved precisely when the head HT is exactly two fifths of the effective height Heff and the Froude number at the tailwater attains the value 1. In algebraic terms, the answer to the search for the optimum operating point is:

Table 1 shows a comparison of key factors at the optimum operating point for hydropower and wind power. Abbildung 3: Cordierdiagramm

WHAT IS THE IMPACT OF MACHINE TYPE AND DESIGN ON THE HYDROPOWER STATION’S INVESTMENT COSTS?

Fluid energy machines align in similar linear fashion with respect to their tip specific speed. This enables a systematic typography of machines. During the planning stage, engineers only need to look at the Cordier diagram to determine at a glance, for example, the machine diameter for each type of machine at a given rotational speed, head and volume flow. Or alternatively, they may want to determine the required rotational speed of the machine at a given installation space, head and volume flow. The practical applications of the Codier diagram are very varied indeed. Having calculated the known optimum operating point (as per [Pelz, 2011]), one can use the Cordier diagram to select a machine and estimate its diameter and rotational speed. For example, when using a synchronous machine as a generator, it is possible to estimate the required rotational speed based on the commercial frequency and the number of pole pairs, and the diameter number can be directly read off the Cordier diagram. Figure 3 shows that the diameter number for displacement machines which includes waterwheels, Archimedean screws, etc. - lies in the range 2 < δ < 100. For high-speed axial machines, it is possible to achieve diameter numbers of σ = 1. The diameter number is proportional to the actual geometric diameter size. This means that when using an axial machine as opposed to a displacement machine, the machine diameter can be reduced by at least 50%.

Using the method introduced in the previous section, we are now able to optimise the energy output and, consequently, the financial yield in the form of the power station’s operating income. In the following, we shall introduce a possible approach to the systematic minimisation of investment costs. A useful tool that we may employ for this purpose is the Cordier diagram (Figure 3). This diagram shows the tip speed ratio [Keller, 1934] against the diameter size [Baashus, 1906]. The Cordier diagram exerts a similar fascination on the research engineer as the Hertzsprung-Russell diagram. This shows the distribution of the stars along certain lines on the brightness/temperature plane, starting with

The crucial information from this is that in small-scale hydropower stations, axial turbo machines always have the lowest performance-specific investment costs, thanks to their high power density. This is because an initial approximate calculation shows that the investment costs are proportional to the cubed diameter. Waterwheels, Archimedean screws and similar displacement machines, on the other hand, incur high investment costs at relatively low power yield. This settles the question of which machine to select in terms of investment costs. This only leaves the question of how the actual design of the machine impacts the investment costs. In his paper “Design and Optimization of Small Hydropower Type Series for Surface Watercourse” [Metzler, 2012] the author examines the influence of modular construction designs on investment costs. Specifically, he addresses the question whether choosing several less powerful machi-

Table 1: Comparison of the theories of Betz and Pelz

This answers the question of how to determine the maximum yield. However, we still need to determine what options there are to reduce the investment costs in a systematic fashion.

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nes over a single machine may be advantageous with respect to investment costs, It can be shown analytically that the investment costs are indirectly proportional to the square root of the number of modules, i. e., that they decrease when the number of modules increases:

investment costs, we can state that axial machines achieve a cost optimum in smallscale hydropower operations, with modular arrangements holding an additional cost cutting potential.

[Troger, 2008] Troger, M.:“Wie effizient sind Wasserräder zur Gewinnung von Energie in Fließgewässern mit geringen Fallhöhen? ; Diplomarbeit,Technische Universität Darmstadt, Darmstadt, (2008).

References:

[Wissel, 2008] Wissel, S. et. al.: Stromerzeugungskosten im Vergleich; Arbeitsbericht Institut für Energiewirtschaft und Rationelle Energieanwendung, Universität Stuttgart, Stuttgart, (2008)

[Pelz, 2011] Pelz, P.: Upper Limit for Hydropower in an Open-Channel Flow, Journal of Hydraulic Engineering; ASCE /; DOI:10.1061/(ASCE)HY. 1943-7900.0000393; (2011). [Pelz, 2012] Pelz, P., Metzler, M.: Optimization of power specific Investment Costs for small Hydropower; Proceedings 17th International Seminar on Hydropower Plants; Vienna, (2012).

Figure 4: Schematic cross-section through a hydropower arrangement with Z=3 modules.

Also, modular arrangements have the benefit of allowing a larger operational area to be served at a high performance coefficient during times of naturally fluctuating volume flows by activating or deactivating individual machine units. So, to answer the question as to the impact of the type and design of the machine on the

[Metzler, 2012] Metzler, M., Pelz, P.: Design and Optimization of Small Hydropower Type Series for Surface Watercourse; Proceedings 17th International Seminar on Hydropower Plants;Vienna, (2012). [Baashuus, 1905] Baashuus, N.: Klassifikation von Turbinen; Zeitschrift des Vereines Deutscher Ingenieure VDI; Band 49; S.92-94, (1905). [Keller, 1934] Keller, C.: Axialgebläse vom Standpunkt der Tragflügeltheorie; Disseratation an der ETH Zürich, (1934).

Authors: Univ.Prof. Dr.-Ing. Peter Pelz Dipl.-Ing. Manuel Metzler Chair for Fluid Systems Technology Technische Universität Darmstadt Magdalenenstraße 4 D-64289 Darmstadt phone +49 6151 16 3353 fax +49 6151 16 2453 manuel.metzler@fst.tu-darmstadt.de www.fst.tu-darmstadt.de

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An interesting assignment presented itself to the Service Team of PRÜFTECHNIK Alignment Systems in a high-head hydropower plant on the river Isar. Marked bearing damage had been identified in a Francis turbine and its associated generator and PRÜFTECHNIK was appointed with the task of identifying the root cause. he hydroelectric power station was commissioned in 1924 and uses a height difference of 26 m in the central Isar Canal to generate electricity by means of four vertically arranged 9-MW Francis turbines. In this power station, the generator sits above the turbine and is connected via a plainbearing mounted vertical shaft (Figure 1). The water that accumulates in the Isar Canal above the power plant flows from the south. In the rest of this report, upstream will be used to indicate this flow and downstream the flow of water discharged from the power plant to the north. The terms east and west will be used to indicate those directions respectively.

photo credits: Prüftechnik

MARKED WEAR ON THE PLAIN BEARING OF A FRANCIS TURBINE - A POTENTIAL ALIGNMENT ISSUE?

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rator’s overhaul team therefore conducted a plumb line test on the plain bearing from the upper side of the generator. This indicated an apparent 2-mm downstream misalignment of the bearings. The power plant operator contacted PRÜFTECHNIK Alignment Systems to perform a laser measurement to confirm the results of the plumb line test. The Service Team of PRÜFTECHNIK carried out the measurement in two stages.

photo credits: Prüftechnik

HIGH ACCURACY WITH A LASER-OPTICAL MEASUREMENT SYSTEM The first stage involved checking the alignment of the bearings to one another. This was

done using CENTRALIGN® Ultra laseroptical measurement system. This device measures the alignment of bores and bearings relative to one another to a high degree of accuracy. First, the system’s laser was mounted on the upper generator bearing using a magnetic holder (Figure 3). The counter piece to the laser is the sensor. Mounted on a pointed bracket, it was clamped in place using a special quick-assembly holder in the plain bearing being measured in a way that allowed it to be rotated (Figure 4). The measurement was made by sampling several measurement points on two measu-

copyright: Wikipedia

UNEVEN WEAR ON THE PLAIN BEARINGS During the course of a scheduled overhaul, atypical uneven wear was discovered on the plain bearing of the Francis turbine and the lower plain bearing of the generator. The wear on the generator bearing occurred on the upstream side and that on the turbine (Figure 2) on the downstream side. The ope-

Figure 2: Wear on the downstream side of the turbine

Figure 1: Arrangement of the generator and turbine

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Figure 3: Assembly of the laser


UNEVEN WEAR RESULTING FROM BEARING MISALIGNMENT Together with the bearing alignment measurements, the pattern of the shaft movement was also a good indicator of uneven wear on the plain bearings. While the bearings were correctly aligned east-west, they appeared to be misaligned along the upstream-downstream axis with the lower generator bearing being 0.3 mm too far downstream. This explained the shaft contact and thus the increased wear on the upstream side of the plain bearing. A similar pattern could be seen on the turbine bearing. In this case, the bearing was 0.15 mm too far upstream. This matched the wear pattern on the lower turbine bearing which was concentrated on the lower downstream part of the bearing. The results therefore confirmed the power plant operator’s initial suspicions that the uneven wear occurring on the plain bearings was caused by some form of misalignment. The reports thus formed a good point of reference for subsequent actions. The lower generator bearing was corrected by 0.3 mm on the upstream side and the upper axial support bearing was levelled slightly by 2/10 mm.

Figure 4: Assembly of the sensor

A follow-up to the bearing alignment measurements allowed the Service Team of PRÜFTECHNIK to use the new system ROTALIGN® Ultra Hydropower to measure the bearings of a two-part vertical shaft (the drive shaft between the turbine and the generator). In the meantime, the two 4-metre long segments of the existing shafting had been reassembled. The initial impact tests went well, with neither the turbine nor the generator exhibiting any significant vibrations. The realignment of the bearings had obviously done the trick. However, it was now interesting to note how the two shaft segments were positioned relative to one another. This would make it possible to check the correction of the plain bearing channel. If there had been any misalignment, the shafting

would have bowed. The team also wanted to identify the position of the shaft relative to the perpendicular. Conventional methods such as using a plumb line are unsuitable in this case. Under optimum conditions, this test device can achieve a level of accuracy of approx. 0.5 mm/m, which is insufficient. This is where ROTALIGN® Ultra Hydropower measurement system from PRÜFTECHNIK comes into its own. The system comprises the powerful ROTALIGN® Ultra platform and the highprecision INCLINEO® inclination measurement device. INCLINEO® is a highly accurate electronic inclinometer which records relative inclination values to less than 0.01 mm/m, which it then transmits to ROTALIGN® Ultra wireless to be analysed and displayed. photo credits: Prüftechnik

ring planes on each plain bearing. The laser merely acted as a reference line for the sensor. The sensor then transmitted the measurement data wireless to the control unit of CENTRALIGN® Ultra. The inclination of the individual plain bearings themselves was calculated in addition to their alignment to one another. The measurement system of ROTALIGN® Ultra is capable of achieving measurements accurate to 1 – 2/100 mm per meter of the measured section. The generator’s upper axial support bearings have a strong impact on the position of the vertical shaft. Any angle error in this bearing will affect the radial movement of the plain bearing. It is therefore essential that this support bearing is levelled. In the second stage of the measurement process, the Service Team of PRÜFTECHNIK checked the level using a high-precision INCLINEO® angle measurement system (Figure 5). INCLINEO® is capable of measuring both absolute (i.e. “under water”) and relative surfaces - and it can do this with the rotating measuring cell in either a horizontal or a vertical position. The upper axial support bearing flange was used to determine whether it was level and flat. Although the flange itself was relatively level, it did exhibit an inclination of 2/10 mm on the upstream side of a flange diameter of 1.6 m.

photo credits: Prüftechnik

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Figure 5: Checking the horizontal alignment of the support bearing with INCLINEO®

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Figure 6: measurement results being transferred via Bluetooth™ to the ROTALIGN® Ultra computer Figure 7a: measurement result; aberration of 0.03 mm on 4 m segment length Figure 7b: measurement result; aberration of 0.65 mm on 8 m of total length of wave

Figure 7b

graphics: Prüftechnik

Figure 7a

Figure 6

The measurement process: as with the other PRÜFTECHNIK devices, ROTALIGN® Ultra Hydropower takes measurements in three stages. Once the sensors have been set up, the dimensions of the shaft sections to be measured are entered in the control unit. The next step involves taking the measurement. The inclination measurement is based on the type of transmission. Two measurements are taken on each of the opposite facing points on a shaft and there are two ways of doing this:

• If the shaft rotates, INCLINEO® is fixed to the shaft and rotates with it (circular measurement) • If the shaft does not rotate, INCLINEO® is placed on two exactly opposite positions on the shaft in succession (static measurement). Measurements are thus taken on each shaft segment for at least each of the four directions (east, west, downstream and upstream). In this instance, the shaft in the hydropower station rotated and INCLINEO® was attached to the shaft segments using a strong

magnetic base. Two circular measurements were taken for each shaft segment in order to check the reproducibility of the measurements. The final step deals with the measurement results (Figure 6). ROTALIGN® Ultra Hydropower showed that the position of the shaft segments exhibited a difference of only 3/100 over a segment length of 4 metres (Figure 7a); a very low value. This proves that the bearings are now very well positioned. Examining the perpendicular gives an offset of 0.65 mm along the entire 8-metre length of the shaft downstream (Figure 7b) and to the west. If required, the perpendicular alignment of the shafting could be improved by adjusting it on the upper thrust bearing. However, according to the operator, this value does not affect the operation of the turbine; rather it is the alignment of the two shaft segments which has the most significance. The shafting itself and the bearing alignment are accurate and very well aligned to one another. The bearing damage on the lower generator and turbine bearing is now a thing of the past. With the new ROTALIGN® Ultra Hydropower the user now has a high-precision, high-speed measurement system capable of determining the relative position of vertical shafts and ensuring they are perpendicular without using the line of sight.

keeps your world rotating

Get it perfectly aligned ROTALIGN® Ultra Hydropower saves time and money Precise vertical shaft alignment. Determines easy and quick ฀ ฀ ฀ ฀shaft runout ฀thrust bearing levelness ฀thrust bearing corrections

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PROVEN QUALITY

Our equipment and services are available around the world. Just contact us.

Made in Germany Global Presence Qualified Support Quality Service

request@pruftechnik.com www.pruftechnik.com


Everything you need to capitalize on small hydro resources Comprehensive solutions from Siemens put everything you need to capitalize on small hydro resources right at your fingertips.

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fo r t h e co ns t r u c t i o n of sm all hydro p owe r p lant s w it h hun dr e ds of su cce ss f ul p roje c t s un d er o ur b e lt . Take a d v ant a g e of o ur uni qu e e x p e r t is e to m a x imize ass e t av ailab ilit y an d p rof it ab ilit y.

www.siemens.com/energy


photo: Panolin

photo: Panolin

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TIWAG Langkampfen Power Plant on the Inn River, Tyrol, Austria

ENVIRONMENTALLY CONSIDERATE LUBRICANTS FOR HYDROPOWER PLANTS Hydropower plants are generally regarded as a very clean source of energy. In order to meet these expectations it is important that operators use environmentally considerate lubricants (ECLs). PANOLIN, a Swiss family-run company located in Madetswil/Zurich, developed its first environmentally friendly, bio-degradable hydraulic oils more than 30 years ago and is one of the international market leaders in this field today.

I

photo: Panolin

n the past lubricants for hydropower plant components were based on mineral oil. In case of a leakage of the plant, however, such products bear the risk of polluting the environment. This risk can be minimized through the usage of environmentally friendly lubricants. ECOFLUID Innsbruck has been successfully working with high-performance ECLs by Swiss lubricant producer PANOLIN in Austrian and South Tyrolean hydropower plants. PANOLIN lubricants are well established not only in the sector of hydropower plants but also in the

ÖBB Braz Power Plant in Vorarlberg, Austria

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sector of hydraulic steel engineering. For many years leading suppliers of power units, plant elements and machine units have been making positive experiences with PANOLIN and therefore it is not surprising that the company has become a major brand in these fields through recommendations. The long-established hydraulic oil PANOLIN HLP SYNTH is used across the country for weir plants, control units, trash rack cleaners and station cranes, while PANOLIN TURWADA SYNTH is used as slide bearing, turbine governor and turbine oil in Francis, Pelton and Kaplan turbines. THE MEANING OF ENVIRONMENTALLY CONSIDERATE LUBRICANTS The first eco-labels for bio-degradable lubricants, or bio oils, such as the Blue Angel or Swedish Standard SS 15 54 34, were established in the early 1990s. The aim of eco-labels is to find ways to diminish the negative effects that leakages can have on the environment. Compared to specifications such as DIN 51524, eco-labels have additional requirements for lubricants regarding their toxic effects on people and mammals and regarding their ecotoxicity, i.e. their harmful effects on plants and aquatic organisms, especially on fish, daphnia and algae. Eco-labeled lubricants are not only bio-degradable but also have a very low level of toxicity. Therefore, the name bio-oil does not adequately describe all their qualities, which is why PANOLIN named their product “environmentally considerate lubricants”, “ECLs”. ECO-LABEL FOR EUROPE In the subsequent years more and more European countries and institutes introduced eco-labels for lubricants. At one point this variety of labels made it almost impossible to put new and approved environ-


ILLWERKE-VKW Rieden-Bregenz Power Plant in Vorarlberg, Austria

photo: Panolin

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cole” (Article 44), which was transferred into act “Loi n° 2010-788 portant engagement national pour l'environnement” (Article 112), prescribes the use of EEL-approved lubricants in environmentally delicate zones. Similar developments can be seen in other countries. With Holland's VAMIL program (tax relief for investments in environmentally friendly machine units) operators receive benefits only when EELapproved lubricants are used. PANOLIN HLP SYNTH E - BIO-DEGRADABLE HYDRAULIC OIL The European eco-label flower has become a symbol of environmentally friendly products, a simple and reliable orientation for consumers. All products that bear the eco-label have been approved by independent bodies for complying with the strict environmental requirements and meeting all fit-for-use criteria. When developing their EEL-approved lubricants the experts of PANOLIN not only met all requirements of the EU environmental protection directives but also made sure the products complied with the company's usual high performance and full compatibility standards. The EEL-approved hydraulic oil PANOLIN HLP SYNTH E, for instance, is fully miscible and compatible with the globally approved PANOLIN HLP SYNTH.

TEWAG Reinbach-Taufers Power Plant in South Tyrol, Italy

photo: Panolin

photo: Panolin

photo: Panolin

mentally friendly products on the European market. In 2003/2004 the EU dealt with this problem and founded the European Eco-Label (EEL) for lubricants. All requirements are detailed in Directive 2005/360/EG “Establishing ecological criteria and the related assessment and verification requirements for the award of the Community eco-label to lubricants“. Lubricants must meet these standards to be EEL-approved. A new era began with this EU directive. Various countries today give approval to plants and machine units in ecologically delicate zones, especially in or next to water, only when EEL-approved lubricants are applied. In France, for instance, act “Loi n° 2006-11 d'orientation agri-

PANOLIN OFFERS TODAY THE LUBRICANTS OF TOMORROW Heinz Hörbst, Senior Manager at ECOFLUID, says with satisfaction: “We made a competitive analysis and, regarding the long period that bio lubricants have been in use, it is absolutely extraordinary that we have not received a single technical complaint with fully synthetic PANOLIN ECLs so far. Thanks to the excellent performance of these lubricants we can now replace the common oil changes with periodic oil inspections and, if necessary, with oil maintenance. PANOLIN lubricants prove their superior quality not only in ecological but also in economical aspects through their long lifespan.” Concluding, it can be said that nowadays environmentally considerate lubricants are not just “nice to have” but have become a must in many aspects.

ETSCHWERKE AG Naturns Power Plant in South Tyrol, Italy

SALZBURG AG, Rott Power Plant on the Saalach River in Salzburg, Austria

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photo: zek

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A crane is used to lift the 6-metre-long GRP pipe sections into the construction pit and move them into position on the prepared substrate at the construction site.

LAYING OF DN3000 GRP FLOWTITE PIPES DURING POWER PLANT RENOVATION IN THE ALLGÄU At the highly traditional Neumühle in the community of Argenbühel in Germany's western Allgäu region, the power of water has been harnessed on the Untere Argen river for centuries; a grinding mill was built there as early as 1754. At the end of the 19th century, the site was electrified by the founders of the Argen works and in 1918 it was equipped with a Francis machine unit. During the course of the 1970s, the operators at the time sold the hydroelectric power plant to the Winter miller family, whose son Hubert Winter then decided to fundamentally modernise the Neumühle power plant, which was showing its age. The new plant concept envisages the installation of pipes for the lower part of the works water channel; the biggest GRP spiral pipes from the Flowtite system with the dimension DN3000 produced by the company AMITECH in Germany were used here.

The low weight of the spiral pipes made from glass-fibre-reinforced polyester resin makes them quick and straightforward to handle at the construction site.

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channel, which is approx. 350 metres long, is still used as far as the old mill, but from there the works water will in future be guided via a siphon line with a subsequent suction pipe into the newly laid GRP pipe string with a diameter of 3.0 metres, which is then guided directly into the new turbine house. photo: zek

T

he most striking aspect about the comprehensive renovation of the Neumühle plant is the relocation of the power production unit from the old mill site to a new powerhouse 50 metres further down the channel, right by the mouth feeding into the Untere Argen river. The old drainage

RAPID LAYING OF THE GRP PIPES THANKS TO INNOVATIVE CONNECTOR SYSTEM When in mid-March 2013 the AMITECH FLOWTITE pipes DN3000 for the new works water pipeline and DN2000 for the necessary undersluice channel are delivered, the construction company Ebert has already perfectly prepared the channel excavation below the old power plant site together with the rough and fine levelling. Under the watchful eyes of AMITECH project manager Jochen Auer and construction site engineer Uwe Pletz, the 6-metre-long sections of pipe made from glass-fibre-reinforced polyester resin are lifted by crane into the construction pit and moved into position there. The construction company has specially produced a steel cross which matches the diameters of the pipes and is attached to the coupling of the GRP pipe which is to be laid. A digger then uses its scoop to press against the attached steel cross and pushes the new section of pipe into the coupling of the existing pipe string which has been well greased beforehand. The AMITECH connector system of the patented


photo: zek

The steel cross made especially for the laying process is used by a digger to press against the pipe sections.

The couplings of the pipe sections are prepared for being joined together.

FLOWTITE series with an interlocking seal produces a specific noise when the sections of pipe are locked together: "When it clicks, it fits," says Jochen Auer in describing the audible sign of success when joining the pipes together with a wink, "with this system we are able to lay up to over 100 metres a day when the conditions on the construction site are in our favour." HYDRAULIC PIPE PROPERTIES PERSUADE THE OPERATOR In addition to its sealing function, another advantage of the connector system is also a certain flexibility when laying the FLOWTITE GRP pipes. The pipe is moved straight into the coupling and it can then be adjusted slightly so that it is possible to work flexibly in a certain range, but not beyond the sealing element. In total, 48 metres of DN3000 pipes of the pressure class PN6 for the works water and 61 metres of DN2000 pipes for the undersluice channel of the new power plant are being laid at the Neumühle site. The developer Hubert Winter is also very satisfied with the GRP pipe strings from the company Amitech: "With the relocation of the powerhouse further down the channel and the hydraulically perfect properties of the AMITECH FLOWTITE pipes, we have now gained a total of approx. 70 cm of net drop for generating power at the new site." With a current total gradient of around 7 metres, the boost in power gained from the new plant concept is therefore around 40 kW. EFFICIENTLY DESIGNED KAPLAN TURBINE DELIVERS NOTABLE BOOST IN PERFORMANCE And in order now to also make efficient use of the optimised drop in gradient in the new powerhouse in energy terms, Hubert Winter decided to install a double-regulated Kaplan turbine from the company HSI Hydro Engineering there. This 5-vane turbine with a vertical axis and an impeller diameter of 1.50

metres will by the end of 2013 replace the almost 100-year-old Francis machine unit from the old mill site and, together with an equally new residual water turbine at the restored discharge weir, now supply twice the annual working capacity to the grid. Incidentally, at the weir a water volume of up to 10.5 m3/s can be drawn into the discharge of the works water channel, but with the design of the Kaplan turbine the main attention was paid to the throughflows of between 4 and 8 m3/s as in this range, with an opening of approx. 45 – 80%, the turbine can be operated in the best efficiency range of around 90%. Coupled directly to the turbine shaft, a permanent magnet generator will turn the mechanical work into electrical energy. The PM generator, which is smaller and lighter compared with conventional units, also offers a persuasive choice with high efficiency in the partial load range. NEW TYPE OF FISHWAY UNDER DISCUSSION As part of the restoration work, a series of measures to support the ecology of the waterways will also be implemented, for example a specially laid lock flow bypass which, competing with the turbine outflow from the new powerhouse, is intended to point the fish

fauna in the Untere Argen river in the right direction towards the discharge channel in the direction of the weir. And if the power plant operator Hubert Winter gets his way, a new and innovative type of migration aid should soon enable the fish at the weir to climb up into the headwater. This is because, in addition to the conventional solutions, consideration is also being given to a newly developed fish lift which in a vertical DN3000 GRP pipe is intended to transport the aquatic water fauna into the headwater by means of a floating acrylic glass basket. Developer Hubert Winter is still coy about revealing too many details of this pioneering idea, but the advantages of rapid and straightforward transportation of the fish to the headwater with drops of up to 30 metres and more, coupled with a design which saves space and costs and has comparatively low operational throughflows, seem to be hard to deny. The operator would like to be connected to the grid with his fully renovated plant by the end of this year. Together with his Thalerschachen hydroelectric power plant, which is also situated in Argenbühel, Hubert Winter will thus be generating a considerable proportion of the power required by this Allgäu community. photo: zek

photo: zek

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The casings for the turbine suction pipe are already waiting to be deployed at the construction site.

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A two-piece housing was used, allowing a subsequent installation without moving the pipes.

photo credits: Straub

photo credits: Straub

The STRAUB-OPEN-FLEX 4H 1670 mm used for installation and pressure test.

THE SOLUTION FOR MONITORING AND SECURING PENSTOCKS AGAINST ROCK DEPRESSION If the rock starts to move there are certain dangers for the installed penstocks: axial misalignment, angular deflection and changes in axial length at the joints. The Vorarlberger Kraftwerke AG was confronted with this situation at the Austrian Klösterle power plant. It was not easy, but eventually a solution to this problem was found. STRAUB Werke AG, based in Wangs, Switzerland, developed a special system with casing shells and sealing sleeves, offering the penstock the required flexibility in the affected areas.

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s the largest local energy provider, Vorarlberger Kraftwerke provides 370,000 people with a reliable power supply. The Vorarlberger Illwerke plants (VI) generate additional peak load power. The Alfenz River is dammed at 1,340 m above sea level and directed through the 5.1 km long Albona and Burtscha II tunnels to the Burtscha reservoir, which has a capacity of 6,900 m³. From this reservoir, the water is fed through a ductile iron pipeline to the Klösterle power station and then returned to the Alfenz River. All water pipelines are under ground. The installed power plant output of 16,000 kW provides an annual power generation of 60.5 m kWh. The tunnel and pipeline were built in 1994. The PAM ductile pipeline is connected using spigot and bell sockets, rests on concrete bases, and is secured using brackets. The geo-

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logical conditions are unstable and it became clear over time that the rock in the middle section of the tunnel was sinking diagonally over a length of over 100 m. This movement was increasingly resulting in axial misalignment, angular deflection, and changes in axial length at the joints. In view of these changes, VI commissioned local consultants to measure the movements and, based on their findings, design a solution that would accommodate them. The survey determined a continuous increase in the pipeline length of 210 mm by 2008 and 870 mm by 2045 (refer to the diagram). CONFINED SPACE IN THE TUNNEL The engineers tested solutions involving flanged compensators as well as dual-gasket couplings to allow sliding. However, the settled area was more than 200 m along a very nar-

row passageway in the tunnel, meaning that only two people could transport the connectors. The weight of each component could therefore not exceed 50 kg. But the approaches proposed involved heavy products that could not be dismantled, so that the tunnel would have had to be enlarged and the pipelines moved. Because of the very high costs and amount of time needed, VI sought other, more appropriate, solutions. THE SOLUTION After the initial contact with the local consultants, STRAUB produced a first prototype featuring welded-on lugs. Installation of the pipe coupling in similarly confined conditions was also simulated and a successful pressure test was carried out. The STRAUB-OPEN-FLEX 4 H 1,670.0 mm pipe coupling met all the criteria. It can


accommodate changes in length of up to 200 mm, can compensate for up to 15 mm expansion and contraction, and can be dismantled into two halves. The weight of the individual components is under 50 kg, and the components can easily be installed by two people. The compactness of the components allows easy transportation inside the tunnel to the connection points. The hot dip galvanised pipe couplings, protected from corrosion by a special coating, were installed within hours, and no additional work was required to be done on site. IMPLEMENTATION OF THE PROJECT A specialist team from STRAUB instructed the workers on site, demonstrating the installation of the first STRAUB-OPEN-FLEX and providing continuing support. Three workers were required to instal the couplings - one on each side of the pipe and a third on it. All three pipes in the critical area were supported between the spigot and bell sockets and then cut twice. The gap between the pipe ends was approx. 30 mm at the beginning. The cut surfaces were sealed by applying a corrosion protection agent. First, the 200 mm wide steel strip insert was placed around the pipe and the sealing sleeve placed on top of it.

graphics: Straub

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Situation in 1994: New pressure pipeline

Prognosis for 2045: Rock movement, leading to deformation of the pressure pipeline, is absorbed by STRAUB-OPEN-FLEX couplings

Then the two halves of the casing were placed over the sleeve from the top and bottom, and the closures tightened using the torque wrench. The position of the coupling was marked on the perimeter of the pipe around the casing. All six pipe couplings were installed within one day, allowing the pressure tests on the installed couplings to be carried out without delay.

ON-GOING MONITORING OF MOVEMENT By continually monitoring the markings, engineers can determine when the movement within the coupling has reached 15 mm. At

that point the locking bolts are undone and the sealing sleeve lifted far enough for the sealing lips to move back to the starting position. This can be repeated until the full range of 200 mm is exhausted, when the next coupling can be brought into play.

Our modular PLUS Add-on programme for the Illwerke project: w The most effective solution w Perfectly matched components w Flawless operation

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photo credits: TechnoAlpin

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In total, TechnoAlpin installed around 8.6 kilometres of ductile cast-iron penstock pipework in various sizes and pressure ratings.

DN400 PN85 FOR ARTIFICIAL SNOW IN RIED When it comes to snowmaking, the resort of Kronplatz (South Tyrol, Italy) has successfully put their trust in the know-how of specialist TechnoAlpin, which is headquartered in the South Tyrolean capital of Bozen. Considering the proven track record in power plant and water pipework engineering of the firm’s Water Solutions division, the resort officials again decided in favour of TechnoAlpin and their expertise for installing the pipework for the resort’s new “Ried Slope”.

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awarded to TechnoAlpine is for all line material, hydraulic material, joints, aluminium and data cables, and 13 snow generators. Along the slope TechnoAlpin installed 4.5 km cast-iron pipes of Class DN 400 PN85 – PN40, 2.7 km of Class DN 250 PN40,

as well as 590 m of Class DN150 and 1.4 km of Class DN125. The material used consisted of System AKPINAL® cast-iron pipes by Saint Gobain. This system was designed specifically for use in technically difficult terrain. Considering the high pressures the pipes photo credits: TechnoAlpin

he new Ried slope, a downhill run that leads from Kronplatz to the valley in Percha, makes the ski resort More easily accessible than ever before. The new section covers a 4.7 km stretch that branches off from the Spitzhorn slope. The contract

Six high-pressure pumps and eight submersible pumps ensure that the water gets to the snow generators. Left: during installation / Right: during operation

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graphics: TechnoAlpin

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TYTON Dichtunggasket TYTON

Retaining Haltering ring

360° Welded seam Schweißwulst

The longitudinally stable Tis-K© socket joint system by Saint Gobain provides a fully tight-fitting, tension-resistant 360° joint. Its offers the great advantage of eliminating the need for concrete thrust blocks, even in difficult terrain.

have to withstand, the requirements are very demanding indeed.

PLANT ENGINEERING EXPERIENCE IN MORE THAN 40 COUNTRIES Efficient planning and dimensioning of pipework is not only essential in snowmaking, but also in power plants, drinking water and sewage works, and many other application environments. By now, TechnoAlpin has successfully installed pipework systems in more than 40 countries worldwide. Along the way, the firm has acquired the necessary sophisticated know-how for implementing custom tailored systems that meet individual local requirements.

photo credits: TechnoAlpin

PRESSURE TEST AT 132.5 BAR The Ried slope project marked the first time that DN 400 pipes with a PN85 pressure rating were used for snowmaking purposes. Many years of experience in pipework construction in difficult terrain have made the TechnoAlpin engineers highly sought-after experts in this field. This is why Techno-Alpin also supervised the process of installing the high-pressure rated pipes. The ALPINAL® system with Tis-K© joints by Saint Gobain is

excellently suited for high-pressure applications like these. In fact, it is the only double chamber joint with a fully tight-fitting 360° retaining ring, i.e. one that fits around the full circumference of the pipe. Depending on the nominal values of the installation, this longitudinally stable socket joint system is suitable for internal pressures up to 100 bar. With this joint system, there is no need for concrete thrust blocks to secure the pipe, even in rough and difficult terrain. With qualities like these, the Tis-K© joint also had no difficulty in passing the type test at 132.5 bar under maximum angulation and shear load.

14 PUMPS UNDER PRESSURE Six high-pressure pumps and eight submersible pumps were installed to move the water from the intake to the Kronplatz summit. The pumping station and pipework system can be thought of as the ‘heart’ and ‘arteries’ of snow generating equipment. Reliable snow generating therefore depends crucially on high-quality materials, machines and components that work reliably and stably even under the most adverse of conditions. This is because even the most powerful of snow generators will be powerless without an efficient, reliable water supply.

Pipe burst valve with sensor DN150 - DN2400 I-39100 Bolzano · T +39 0471 550 550 · watersolutions@technoalpin.com

Connecting point for one of a set of 13 snow generators

www.water-solutions.it

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GRISONS-BASED VALVES SPECIALIST FOR SAFE HYDROPOWER PLANTS photo: ADAMS

Swiss company ADAMS Schweiz AG, the successor company of former AMSAG, has been producing valves for a vast range of applications since 1979. The renowned family business is part of the Adams group, which employs 400 people and has production sites in Switzerland, Germany and the USA. ADAMS Schweiz AG is based in the scenic region of Serneus, in the canton of Grisons. In addition to the production of industrial valves, the company now specializes in the development and production of shut-off valves for hydropower plants.

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hanks to the rapidly progressing technical development of the past 100 years it is now possible to generate an enormous amount of energy through hydropower. To fully exploit this potential, reliable hydropower plants are needed. The hydropower competence center of ADAMS Schweiz AG has been offering a range of specially developed shut-off valves for more than 30 years. Depending on the design of the plant, the company develops individual complete solutions (e.g.: inlet pipes, valves, pipe spools, discharge pipes, by-passes) for both new installations and modifications of existing units, ideally tailored to the clients' needs. These units are manufactured in Switzerland or at Adams Armaturen in Herne, Germany.

photos: ADAMS

COMPREHENSIVE PROTECTION FOR HYDROPOWER PLANTS ADAMS's hydropower program comprises various fields of operation: pipe burst protection, turbine protection and environmentally friendly discharge of water. The entire product line-up guarantees absolutely reliable

ADAMS spherical valve DN 1350 PN80 at the turbine inlet of the Martigny-La Batiaz power plant.

protection and water-proof closure in any challenging situation. PENSTOCK PROTECTION BUTTERFLY VALVE The common penstock protection butterfly valve is installed in front of the penstock at the bottom of the dam. It is used to shut off the water flow in case the downstream penstock is destroyed or damaged by material fatigue, uncontrolled movement of earth or sabotage. This safeguards the reservoir against draining off entirely and helps prevent further damage. The safety valves are mainly made from welded steel, feature stream-favorable

valve discs and come as single or double valves. The valves are equipped with hydraulically regulated servomotors for the opening mechanism and a lever with a counterweight for the forced closure mechanism. TURBINE INLET SAFETY VALVES The safety valves are mainly made from welded steel, feature stream-favorable valve discs and come as single or double valves. They are delivered with hydraulically regulated servomotors for the opening mechanism and a lever with a counterweight for the forced closure mechanism. For any special require-

Images of a spherical valve.

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photo: ADAMS

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Cone jet valve with butterfly valve as the bottom outlet of the Barrage de l'Hongrin power plant.

SPHERICAL VALVES Spherical Valves are specially crafted shut-off valves for high pressure situations. They are installed at the end of the penstock, in front of the turbine and are mainly used to close off the penstock at normal shutdowns or at turbine load rejections. Their casings are either cast or made from welded steel, the rotor is usually forged. The shafts are either forged or bolted and are stored in permanently lubricated sockets. Usually the metallic sealing rings are placed on the downstream side of the casing and are driven by water pressure or bio-degradable hydraulic oil, i.e. they are pressed against the rotor after the closing movement. An advantage of sealing rings positioned on the upstream side of the casing is that they make a replacement of the bearing seal on the spherical valve possible, since this seal is used as a closure system and the penstock does not need to be discharged. CONE JET VALVES Cone jet valves are used for the energy dissipation of dams. The valves are operating on a cavitation free basis through a comprehensive control system. In addition to enriching the water with oxygen, they dissipate the energy of enormous flow and pressure rates. Cone jet valves are mainly made from welded steel and operate hydraulically or electromechanically.

- Up- and downstream pipe spools: ADAMS delivers up- and downstream pipe spools with all necessary manholes, discharge nozzles, air discharge nozzles and connecting branches. - Integrated dismantling flanges: ADAMS provides integrated mounting and dismantling flanges attached either directly to the valve or to the spherical valve or integrated in the up- or downstream spools. These flanges are available as movable or fixed joints, both locked for longitudinal forces. - Air inlet and air discharge valves: For the air inlet of penstocks, etc. as ball valves or plate valves. These valves are designed and built according to the requirements of each project. - Overspeed detectors: As stainless mechanical trigger devices for penstock protection butterfly valves. - Hydraulic power and control units: ADAMS Schweiz AG provides hydraulic power and control units for operating the plant components OVERALL PROVIDER FOR NEW INSTALLATIONS AND INSPECTIONS In the planning, production, installation and commissioning of valves, ADAMS is a com-

petent partner for units of smaller nominal diameters and pressure ranges as well as for units with an installation weight of 300 tons. The company's experienced service technicians are always ready to assist its clients during upcoming service or maintenance works. An additional service offered by the Swiss valves specialist is the inspection and modification of shut-off valves and their control units. During these works the units are dismantled and brought to the manufacturing plant or, if transportation is not possible, are inspected on site. The components are cleaned and checked (crack detection, ultrasonic testing according to corresponding standards) and, if necessary, replaced or modified. HIGH QUALITY GUARANTEES SUCCESS ADAMS' international clientele includes the most renowned energy suppliers and power plant operators in Europe. The company has been very successful in the past, but also has a lot of successful years ahead. The key to the consistent success of the Swiss family business from the canton of Grisons was and still is quality, ideal service and high standards for the rendition of services. photo: ADAMS

ments ADAMS offers a variety of actuation mechanisms. The valves are delivered with all necessary components required for a smooth operation.

Inspection works at a spherical valve DN 2000

SDDITIONAL COMPONENTS AND ACCESSORIES Depending on the requirements of the plant ADAMS offers a range of adequate accessories and additional components: - Needle valves: Needle valves are installed in bypass lines with higher current velocity and pressure. They operate manually, hydraulically or electrically. April 2013

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photo credit: C. Theny

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Refurbishing shut-off equipment for power stations has become an important cornerstone in the business operations of Carinthian-based hydroelectricity specialist EFG. Ball valves like the one at the ÖBB power station in Uttendorf are rejuvenated in an elaborate reconditioning procedure that restores them to their original showroom condition. By now, an entire team at EFG is focussed primarily on this task. Picture: Matthias Eberhard, Workshop Manager Johann Leschanz, Managing Director Werner Goldberger, his son Martin Goldberger, Ernst Eberhard, and Gero Pretis at a factory acceptance test in Feldkirchen.

WHEN SHUT-OFF DEVICES NEED A MAKEOVER At the high-head power plants built in this region some forty to sixty years ago, the shut-off devices are in many cases quite old by now. As a result, most operators of such plants are now having their shut-off components completely overhauled and restored to their former splendour. After all, the shut-off devices are the most important security-relevant feature along the motive water stream of a hydropower station. Nowadays, however, putting the restoration plans into practice can get quite complicated, as by now some of the original manufacturers have gone out of business. In many cases the original machine blueprints have been lost as well. Specialising in solutions to these problems, Carinthian hydropower specialist EFG uses latest technologies to restore the complex shut-off mechanisms of yesteryear to showroom condition – and performing all the required installation work along the way. ince engineers have been building high-head power plants in alpine regions, safety has been an important concern. Especially in storage and pumped storage power plants, which may have a gross head of several hundred feet, one can imagine the enormous pressure that the water column exerts on the shut-off components day in, day out. The ability to control this pressure load and withstand possible pressure surges in case of a machine standstill is a central requirement of the applicable security directives. These are designed to protect not just people’s property but, much more importantly, the people themselves. As a result, shut-off devices for controlling the motive water stream were developed as an indispensable security measure to cut off the water stream in case of an emergency. Hydro-

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power engineers in the past have come up with a whole range of shut-off mechanisms of varying designs. This includes everything from shut-off or pipe burst valves to various shut-off sluices, and the commonly used spherical valve, wedged gate valve, and annular valve systems. The respective designs and constructions reflect the different applications and environments in which the shut-off devices are used. Pipe burst valves are fitted at the intake point of a penstock, where the pressure is relatively low. Installed at the other end of the penstock are turbine shut-off devices, which function as a sort of ‘final link’ in the chain of safety mechanisms and are designed to withstand much higher pressures. The devices used at the lower shut-off point are usually ball valves or spheric al valves. The former are more common in smaller-sized

hydropower stations, whereas the latter are typically installed in large-scale facilities.

LOST KNOW-HOW Especially during the 1950s and up until the 1970s, a large number of regular and pumped storage power plants were built in alpine regions to satisfy the growing hunger for electricity. Today, these facilities have reached a technical age when many of the other components are already in desperate need of restoration. This applies particularly to the shut-off mechanisms, which in many cases were operated unchanged since their installation – up until recently, that is. “Over the past few years quite a few large-scale power plants have been putting a revision of their shut-off systems on their agenda. This is partly due to the age of the components, but it is also a requirement


to ensure the necessary ‘re-granting of water rights’. From the operator’s point of view, the problem is that manufacturing the devices from scratch is usually very expensive. Also, finding specialists who have the necessary know-how for a professional reconditioning is becoming increasingly difficult. Sometimes the reason for this is the fact that the original manufacturers have gone out of business or no longer support the particular model, or the original blueprints are lost,” explains Werner Goldberger, Managing Director of EFG Turbinenbau, which has its head office in the Carinthian town of Feldkirchen. This market situation was what got Goldberger’s firm involved in the issue, eventually making it one of the leading providers of reconditioning services for shut-off mechanisms. Hydropower specialist EFG, which is primarily known in the industry for its high-quality turbines, has also been making its mark with a growing series of reconditioning and revitalisation projects. This, as Werner Goldberger points out, was one of the basic preconditions for EFG’s successful entry into the market for shut-off systems.

The reconditioned ball valves for Fragant storage power plant of operator Kelag, ready for factory acceptance testing.

over the following years ready like a Who’s Who of Austrian hydropower: IKB, Verbund, Kelag, as well as numerous private operators. Increasingly, requests have also been coming in from across the border. For the hydropower specialists in Feldkirchen this development represents more than just the startup of a second business unit next to their turbine manufacturing operation, but also a significant growth in valuable know-how. Says Goldberger, “Of course we are learning new things with every new reconditioning project. It’s not just interesting professionally to know about the technical approaches that the hydropower engineers have chosen for their designs. We are also interested in acquiring the knowledge and know-how that is needed to professionally recondition any common type of shut-off device. This is a definite advantage in the market. Personally, I must confess that working on a complex piece of machinery like a spherical valve can sometimes be even more demanding and more interesting than most turbine constructions for new power plants. photo credit: EFG

WORKING FOR THE ‘BIG PLAYERS’ Barely ten years ago, EFG won the contract for reconditioning its first spherical valve. The contract was awarded by ÖBB (Austrian Federal Railways), one of Austria’s largest hydropower providers. The contract called for a full reconditioning of the shut-off system at the Spullersee railway power station. It was the successful completion of this project that sparked the decision to venture further into this new segment. The list of customers that have sought the services of EFG

photo credit: C. Theny

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The legendary Von Roll shut-off systems are considered to be among the highest-quality units of their type in the hydropower industry. Due to their high technical complexity, reconditioning them requires extensive know-how. EFG have already reconditioned several units of this type.

STEP-BY-STEP PROCEDURE Generally, the reconditioning of these machine parts proceeds in several stages. Matthias Viertler, a seasoned machine engineering expert at EFG, describes them as follows: “First, we take out the shut-off device and transport it to back our workshop. Of course, we keep a seamless documentation of the entire process from the start. That’s not just for our own benefit, it also benefits our clients. Back at the workshop we completely dismantle the device and sandblast the parts. Next, it’s off to non-destructive materials testing and a whole series of other tests. At that point we consult with the client to determine the next steps and the remaining process. This gives us the chance to assess the actual condition of the individual parts in detail. Which parts are still in working condition? Which ones are defective? Which ones need reconditioning or re-manufacturing? These are the main questions at that stage. This usually leads to a combination of welding work and manufacturing of new parts. After that, new gaskets are put in and the corrosion protective coating is applied. The finished device then undergoes various function tests and an intense test run to verify its pressure bearing capabilities. After the factory acceptance test with the client, it’s over to the installation team again, who reinstall the device.” LATEST METHODS FOR BEST RESULTS Quite obviously, the devil is in the detail at every single step in the process. The list of potential problems that the EFG specialists may be confronted with is virtually endless. “It’s not uncommon that we come across invalid labels on some parts that were just left unchanged. Certifiers today would never approve parts like that. All parts are expected to be state-of-the-art technically to get an approval. It’s up to the operator to provide all the missing technical documentation. April 2013

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Together with appropriate certified bodies we are happy to assist our clients with this. By now it’s not much of a problem any more if the original blueprints and documentation are no longer available – which is not at all uncommon. In that case we just measure the parts at a 1:1 scale using our modern scanning systems. The data is then transferred electronically to the CAD software and transformed into a 3-D model. This allows us not only to retrieve and process 3-D models fairly quickly and easily, it also offers clients a complete technical documentation of their shut-off device,” says Daniel Zaminer.

Matthias Eberhard at the activation test for the service gasket.

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photo credit: C. Theny

DAMAGE CAUSED BY SAND AND PEBBLES The types of damage shut-off devices may sustain are as varied as the types of shut-off devices themselves. “When you take a look inside a spherical valve after half a century of use, you’ll notice that it’s primarily sediment, pebbles, sand and pieces of wood that cause mechanical damage. The small grooves that are cut into the steel surfaces under high pressure keep eating away at the metal slowly but steadily and cause the system to leak over time,” explains Mathias Viertler. Of course, general wear and tear contributes to this effect as well. The more repositioning movements a shut-off device has to perform, the more intense the steady load on the sealing gaskets becomes. The bearing bushes may also be chewed away under the pressure, unless they are lubricated properly and regularly. This applies particularly to spherical valves, due to the one-sided surface pressure that is typically exerted on this type of device. “We found that the rack-and-pinion assembly in the gearing of the spherical valve were also in urgent need of repair. Here is a quick rundown of how these parts work: The sprockets of the pinion shift the gear rack, which turns the ball head into its closing position. The pres-

photo credit: EFG

After its thorough reconditioning, the spherical valve of the IKP power plant Untere Sill was reinstalled and taken into operation again, ready for further decades of service.

surised slider plate then ensures proper sealing of the device so no water can get through. In case the sprockets are damaged beyond repair, the flange clearance can be restored with a remanufactured pinion and refinished gear rack; this is achieved by shifting the profile of the sprokkets. Even if it does not sound very exciting,” says Viertler, “rebuilding the sprockets from scratch does take a lot of effort.” Where damage is concerned, the pressure level is a crucial factor, especially in turbine shut-off devices. “High pressures above 70 or 80 bars – which are quite common – may warp even large steel parts. That is why the bolted connections on the partition of a spherical valve are positioned tightly next to each other and are hydraulically pre-loaded due to the intense preload forces. It takes a lot of attention and precision to open and tighten such block flange connections to avoid possible warping, which could lead to the journal pin getting stuck,” says the expert.

THE NEED FOR HIGH PRECISION IN MANUFACTURING As a result, the challenges the reconditioners are faced with are varied and demanding. “Especially the details can get very tricky indeed. Take a task like grinding the ball for a perfect fit in the valve body, for example: It takes a lot of craftsmanship and an incredibly high level of manufacturing precision to get a perfectly tight system with clearances between the metal surfaces of one hundredth of a millimetre. But even a perfectly shaped ball head is not enough to make the valve 100% watertight if there is even the slightest deviation in axial distance between the head and body,” says EFG Refurbishment Specialist Ernst Eberhard, quoting an essential guiding principle for this type of work: “Errors start with a compromise – and the point is to avoid error wherever possible.” Supplementary components such as the bypass system Quite frequently, the sprockets on the gear rack of a spherical valve need to be reconditioned, as in the case pictured here (ÖBB Power Station Uttendorf).

photo credit: C. Theny

photo credit: EFG

Deinstallation of the spherical valve at the Uttendorf power plant in the Pinzgau region in the Austrian province of Salzburg.


and filling nozzles play a rather important role as well. Working on them requires quite a bit of technical know-how and the necessary experience to cope with the many potential problems and challenges. And then, of course, there are the individual needs and wants of the operator that need to be considered as well. Such individual demands, says Matthias Viertler, may even concern things as specific as the abrasiveness level in sandblasting or the type and application of the corrosion protective coating. As he points out, “It’s essential that we cooperate with our client to meet the highly demanding requirements.”

DEADLINES: THE TOUCHSTONE OF PROFESSIONALISM Looking back on the past ten years that EFG has been active in shut-off device reconditioning, its Managing Director can list quite a few interesting reference projects. The complete reconditioning of the spherical valves for IKB at their Untere Sill power station, the ÖBB power stations at Uttendorf and Schneiderau, and similar valve units for hydropower group Fragant/Kelag, for example. A particularly memorable project, he recalls, was the contract EFG was awarded for the reconditioning of four pipe burst valves, including the air valves, at the VERBUND’s hydropower plant near Hieflau in the Austrian province of Styria. What made this project so special was the extraordinary size of the components, which measured an impressive 3 metres in diameter. The other thing that made this project stand out was the extremely tight time schedule, which ‘squeezed’ the whole project into a time frame of only three months. “Especially with largescale power plants, the replacing or reconditioning of components requires long-term planning and meticulous timing of the shutdown. This is quite understandable, considering that downtimes mean a considerable loss of income for the operator. Of course, this puts quite a bit of pressure on us as the contractor. That particular contract really pushed us to the limit. But in the end it was a success, as we finished it all in time,” says the managing director.

photo credit: C. Theny

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The power station at Hieflau (operated by VERBUND) had four pipe burst valves reconditioned by EFG; each of the valves measures 3m in diameter. The sheer size of the construction posed a significant challenge to the EFG team: Gero Pretis, Adi Avramuti, Armin Pretis and Matthias Eberhard (l.t.r.); Refurbishment Specialist Ernst Eberhard (background)

be found primarily in high-head facilities in Switzerland and Western Austria, are on EFG’s list of references. These devices are considered to be expensive and of very high quality, but also a great technical challenge. “In these constructions, the position of the rotary head is controlled by two rotationally symmetric, curvilinear hydraulic cylinders. In my opinion, this is the cleanest and best thought-out solution for any shut-off device in terms of engineering, and experience shows that it has very good maintenance qualities indeed. However, these systems are not exactly easy to repair, as their inner workings are a sort of ‘different world’ altogether. That’s why nowadays they are sometimes replaced by straight cylinders and a rack-andpinion construction – simply because the necessary knowledge is missing in the market. For us, reconditioning a Von Roll system is an exciting, very rewarding challenge, which we

love to take on if we get a chance,” says Armin Pretis from Research and Development at EFG. Although a passionate turbine engineer, Werner Goldberger has developed a great deal of professional enthusiasm for the many different types of shut-off devices that are commonly installed in alpine high-head power stations. Thanks to EFG’s commitment and extensive know-how, this segment has grown into a sizeable contributor to the economic success of the mid-sized firm from Feldkirchen. The issues at the core of the reconditioning business are quite sensitive, as they are all tied to the essential aspects of power plant safety. The fact that some of the largest and most renowned hydropower operators have decided to put these safety issues into the able hand of the EFG engineers may well be seen as a high-profile seal of approval.

EXPERIENCE WITH COMPLEX SYSTEMS The more complex and more difficult the reconditioning of a shut-off device turned out to be, the more experience and know-how the Carinthian hydropower specialists were able to accumulate. By now, there is hardly any commonly used shut-off device that they have not dealt with so far. Even the extremely high-quality Von Roll systems, which can April 2013

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In recent years EDP, Portugal's biggest energy supplier, has decided on a national plan to expand renewable hydropower energy. Today the country's installed hydropower output is more than 4.7 GW. An expansion by another 3.0 GW within the next few years is planned through the construction of new plants and through the revitalization of existing plants. One of the recently revitalized sites, Picote storage power plant in the northeast of Portugal has been equipped with an additional powerhouse during comprehensive expansion works in 2011. Bavarian company Muhr GmbH was responsible for delivery and installation of various large-scale hydraulic steel engineering components for this major international project.

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Technicians of Muhr GmbH in front of the tailwater gates of the turbine outlet

tial as too much unused water was being discharged via the dam. So, in the course of the national hydropower expansion program new ideas for a more efficient expansion of the existing plant were born. NEW POWER PLANT DOUBLES OUTPUT POTENTIAL AT PICOTE A solution was found in the construction of a second storage power plant, named Picote II, photo: Muhr

uilt in 1958 Picote storage power plant lies on the Douro River between Spain and Portugal, however, it is used for hydropower reasons only by the Portuguese. The plant consists of 3 Francis machine units identical in construction and has an installed output of 180 MW and an annual production capacity of 870 GWh. However, the operator EDP saw that the site did not live up to its energy efficiency poten-

photo: Muhr

PORTUGUESE POWER PLANT RELIES ON HYDRAULIC STEEL ENGINEERING FROM MUHR

Inlet structure to the cavern hydroelectric power plant Picote II with a trash rack cleaner and the cylinder for the safety gates

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next to the already existing Picote I, built in a cavern (measurements: 68 meters in length, 23 meters in width and 58 meters in height) 125 meters into the mountain. One and the same basin supplies the new power plant as well as the old one, the water catchment to the approximately 500 meters long underground process water channel was positioned slightly above the existing power house. All access tunnels for construction and installation works add up to a total length of 1.3 km. In 2007 the consortium Voith-Siemens was awarded the contract for installing the electromechanical equipment of the new power plant. The â&#x201A;Ź 56 million contract comprised the delivery of a Francis turbine with a nominal output of 248 MW including the corresponding electric equipment with a 273MVA generator, excitation system, control technology and balance of plant equipment. SEARCHING FOR A HYDRAULIC STEEL ENGINEERING SPECIALIST WITH SPECIAL IDEAS The operator relied on German know-how even for the complex and special needs for the hydraulic steel engineering. A specialist in its sector, Muhr GmbH from Brannenburg in Bavaria, Germany, was ordered in particular to equip the plant with large shut-off valves. The comprehensive order consisted of 2 roller gates as safety shut-off valves for the turbi-


ne inlet (maximum water head of 33.2 meters, constructed for operating with total water pressure), 2 roller gates for the outlet and 3 stop logs. Furthermore Muhr delivered and installed the trash rack including the

trash rack cleaning machine with an integrated 40-tons lifting unit for the stop log. The unit at Muhr GmbH responsible for executing this project was facing new challenges with the new plant Picote II: the large dimension of each component and remote installation sites. Major issues were especially the complex installation of the 45-tons turbine outlet gate within the mountain and the installation of the hydraulic cylinders with a stroke of over 12 meters and a lifting power of 92 tons. PICOTE II COMPLETED AS FIRST PROJECT OF THE EXPANSION The Portuguese client EDP was very satisfied with Muhr's production division HYDROCON for having met the special needs for the hydraulic steel engineering and for having delivered and installed everything on schedule. As an experienced hydraulic steel engineering company with a total of over 2000 power plant installations worldwide Bran-nenburg based Muhr proved once again to be one of the leaders in the international hydropower market by finding special solutions for a large-dimensioned project, such as the new Picote II storage power plant. In the fall of 2011 the new plant Picote II was put into operation as the first hydropower project of

photo: Muhr

The 11.6 m high turbine outlet gate during factory acceptance

photo: Muhr

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Installation of the cylinders for the turbine outlet gates

the new national expansion program. The site on the border river Douro contributes an additional annual average energy capacity of 239 GWh to the Portuguese power supply system.

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THE CUSTOM TAILORED TRASH RACK CLEANER photo credits: Kuenz

Hans Kuenz GmbH from Hard in the Austrian Province of Vorarlberg has been providing trash rack cleaning machines (TRCMs) for the hydropower market since the mid-1960s. One guideline from the early days back then still applies today: the ideal trash rack cleaning machine is the one that perfectly matches the customer’s requirements. That is why Kuenz specialises in customized TRCMs, chiefly for mid-sized to large-sized facilities. The resulting vast experience gained over almost half a century has made the company from Vorarlberg one of the leading providers in the industry.

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eing able to construct powerful, yet economic TRCMs requires extensive experience in hydraulic steelwork construction and machine engineering, coupled with extensive knowledge regarding the specific requirements of hydropower facilities. One company that meets all these criteria – and has done so since its foundation more than 45 years ago – is Hans Kuenz GmbH, which has its headquarters in the Austrian province of Vorarlberg. It was in 1967 when the very first TRCM left the Kuenz production facilities in the town of Hard. Since then, the specific basic requirements for the operation of hydropower stations have changed little, if at all. Still, a few innovations were introduced in the form of technological advancements. These focussed chiefly on areas such as special applications or computer-based control equipment. In general, however, the simple choice today remains between a cable-operated TRCM and a hydraulic TRCM, although a certain preference towards hydraulic machines has emerged over the past decade.

Powerful TRCM with hydraulic cantilever arm at the Rott power plant near Salzburg

The cable operated TRCM with hydraulic gripper at the Rheinfelden power plant moving debris into the rinsing channel system

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photo credits: Kuenz

photo credits: Kuenz

UNDERSTANDING CUSTOMER REQUIREMENTS “Both of these technologies have their merits,” says Samuel Wolfgang, project manager for trash rack cleaning at Kuenz, “and both of them have their upsides and downsides.” He adds: “In the end, the decision which technology should be used in individual cases is up to the customer, unless there is only one logical choice due to the particular conditions, requirements and system.” Regardless of which type of TRCM is selected and for what reason, there is one thing that is always essential for the hydro steelwork specialist from the Western tip of Austria:

Two movable, cable operated Kuenz TRCMs at the Walsee power station

The hydraulic TRCM at the Gamp power station is also used for setting stop logs.


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every machine must be tailored perfectly to the individual conditions and requirements. “The first essential step is to become familiar with the requirements, and to fully understand them. Then we can go about playing out strengths in design and construction to deliver a machine that is precisely tailored to the individual needs and conditions,” says Samuel Wolfgang. Whatever the specific demand – whether it’s a particular rake width or cleaning depth, a special rake technology that’s needed, or certain performance or low-noise standards that must be met – Kuenz has made it its mission to deliver the solution that perfectly satisfies all individual needs and wants.

SILENCE OF THE TRCM Proof of this commitment comes in the form of impressive reference installations, such as the TRCM that Kuenz recently completed for a power station on the River Main. As per the customer’s requirements, the machines of type RRM-H500 were constructed with a semi-/gantry portal. The engineers implemented a way to get to and from the circular dam along a 140° radius. They also developed a new type of gripper rake, which enables not only proper cleaning of the trash rack, but also optimises the disposal of the collected debris.

Comparison of TRCM Technologies Cable-operated trash rack cleaning machine

Hydraulic trash rack cleaning machine

Application environments:

Application environments:

l Locations with bulky, oversized floating debris • Locations with cleaning depths of 7 – 35 m • Applications requiring removal of sediment or large rocks from the bottom of the intake Design: l Closed or open construction design, i.e. WITH or WITHOUT • Vertical or inclined trash racks (without existing guiding frame on the trash rack) winch housing • Trash rack cleaning is performed either with a gripper Gripper rake: l This supports various applications. All kinds of uses and rake in a downward motion, or with a pivot rake moving debris are supported, including grass, household refuse, upwards. Which option is used depends on the characteleaves, twigs and branches up to large tree trunks. ristics of the floating debris, and on imposed specificati• Discharge and disposal system ons and requirements. Hydraulic TRCMs are usually equipped with stationary or • Discharge and disposal system movable containers, with containers being replaced by Whether a swivel chute, tilting flap or movable chute is third-party service providers; an alternative option is the used for cable-operated TRCM depends on the available installation of a stationary pit. infrastructures and the selected disposal system. Disposal is typically by way of a container or directly into the channel system.

locations with restricted spatial conditions on the dam • systems with deep going trash racks • existing infrastructures for cable-operated machines l

A more recent, highly interesting TRCM project was completed by Kuenz GmbH for a power station in Rüchlig on the River Aare in Switzerland. This involved combining a cable-operated TRCM of type RRM-EK45 with a horizontal TRCM of type RRM-T. The main characteristic of this “twin pack” TRCM is the extremely low noise level, which was designed to remain below the 45 dB thresholds, as per the customer’s requirements. Both machines were integrated into a

partially existing infrastructure and rail system. Also, the Kuenz TRCM was designed specifically to be used for moving the existing crane of the facility, which serves for hoisting the stop log. Thanks to the horizontally aligned cleaning mechanism, the space between the narrow screen bars (25 mm) can be cleaned as well. These are only two examples that illustrate the innovative power and know-how of the Hans Kuenz GmbH.

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photo credits: Braun

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The trash rack cleaner of the Sohlstufe Lehen power plant with a length of 29 m is the largest rack cleaner to have ever been built at Vรถcklabruck-based Braun.

BRAUN'S BIGGEST TRASH RACK CLEANER TO OPERATE IN SALZBURG The Sohlstufe Lehen power plant in the heart of the city of Salzburg, Austria, will be put into operation in mid-2013. Works on the plant are currently being finalized. Renowned Vรถcklabruck-based Braun Maschinenfabrik delivered a moveable trash rack cleaner with an exceptionally strong performance. A true colossus of steel, the state-of-the-art trash rack cleaner with an articulated arm has a total length of 29 meters and a transport weight of 67 tons, which makes it a record-breaking job for Braun.

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the Sohlstufe Lehen power plant. The motivation for the realization of this project encompasses not only the expansion of the production capacities of Salzburg AG, the photo credits: maxRIEDER, Erich Wagner

ne of the most exciting and at the same time most ambitious power plant projects in Austria is set to be completed in the city of Salzburg, the home of Mozart:

The new Sohlstufe Lehen power plant in Salzburg is to be put into operation officially in mid-2013. A trash rack cleaning machine with an articulated arm by Braun will guarantee the unhindered flow at the inlet trash rack.

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energy supplier of the federal state of Salzburg, but also the improvement of the flood control and the reduction of the increasing bed degradation of the Salzach River. Furthermore a near-by recreation area for local residents is being built. Thanks to its round and fluent shape the design of the new power plant will be in harmony with the cityscape of Salzburg. To guarantee that this requirement would be met the planning of the project was put out for tender beforehand. Yet another quality of the plant is its high environmental compatibility. The design fully guarantees the required ecological fish passing in the Salzach River at the existing vertical hard basin drop structure. Of course the new power plant will also meet all hydroelectric requirements. With a total installed output of 13.7 MW the plant will provide the local electrical grid with about 81 m kWh annually. This is sufficient electricity for approximately 23,000 households. Furthermore the green electricity produced by


photo credits: Braun

graphics: Braun

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Transport of the trash rack cleaner on a lowbed trailer

The trash rack cleaner during the cleaning process. The grabber is designed to securely collect floating debris of various sizes and diameters.

the plant will save 65,000 tons of CO2 on average per year. The construction works are in their final stages, the power plant will be put into operation in mid-2013.

RECORD-BREAKING MACHINE The trash rack cleaner is a very important component in the construction of a run-ofthe-river power plant of this size and structure. It provides an unhindered flow at the fine rack and directly influences the total degree of efficiency and the plant's availability. Only a solid, efficiently operating and high-quality rack cleaner can prevent floating debris from affecting the power plant operation in the long run. With the trash rack cleaner of the Sohlstufe Lehen power plant experienced hydropower plant operator Salzburg AG relies on the expertise of Braun Maschinenfabrik, one of the most renowned companies in this field. With the contract for the trash rack cleaning machine with an articulated arm for the power plant in Salzburg, Upper Austrian-based Braun had to deal with entirely new dimensions. Measures and weight of the various parts are breaking most existing in-house records. SOPHISTICATED CLEANING MECHANISM The movable trash rack cleaner is designed with an articulated arm and features a traction drive as well as a rotary drive. The balance weight, the cabin, the switchboard and the hydraulic power unit are installed on the rotating upper operator console. The main arm with a length of 14 meters and a weight of 7 tons is fixed on the upper operator console as well. During the cleaning process the cleaner rake, which is attached together with the grabber

to the lower end of the 15 meters long articulated arm, enters the fine rack. At this stage the grabber is open. It is not until the grabber reaches the water surface that it closes around the debris. The cleaner rake is rotatable around the vertical axis and slews through the rotary drive. The collected debris falls into the rake through this “spooning-like motion.” Subsequently the grabber closes and the trash rack cleaner is moved to the container. For emptying the grabber bottom is slewed all the way down so the debris falls out of the rake. During this movement the grabber is securely holding on to all differently sized debris. Furthermore the movable trash rack cleaning machine has a built-in stop log lifting unit.

80 TONS ON THE ROAD Braun Maschinenfabrik had to face huge challenges not only with the manufacture of the extraordinarily large trash rack cleaner, but also with its transportation, which was carried out in a heavy load transport at night. The lowbed trailer including the entire cargo had a weight of 80 tons. In March this year the experts of Braun delivered, installed and put into operation the colossus of steel. The installation of the trash rack cleaner was one of the last steps in the completion of the new plant. Judging by the high product quality for which Braun is known this important functional element will provide an unhindered flow at the inlet trash rack for many years to come.

Trash rack cleaning systems Hydro steel structures / screens

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MASCHINENFABRIK

A-4840 Vöcklabruck · Tel. +43 (0) 76 72 / 72 463-0 · office@braun.at · www.braun.at

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photo credits: Urbas

Niederaichbach power plant: Realistic photographic portrayal of the cable trash rack cleaner

THE TRASH RACK CLEANER - SELECTION CRITERIA AND APPLICATIONS

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Werfen/Pfarrwerfen power plant: cleaning depth approx. 15 m / weightbearing capacity at 15 m radius 15 kN cycle time for a trash rack < 15 min

Mテシhlrading power plant: cable trash rack cleaner with loading crane, floating debris grill and fully automatic unloading tipper

photo credits: Urbas

VERBUND INNKRAFTWERKE GMBH REPLACES CABLE TRASH RACK CLEANER IN NEUテ傍TING. VERBUND-Innkraftwerke GmbH operates 13 power plants on the River Inn in Bavaria, including the Neuテカtting power plant. The plant began operating in 1951 and has a plant output of 26 MW. Due to its age, the machine already displays heavy signs of wear and increasing malfunctions. As part of revitalisation work at the power plant, a very powerful, self-propelled and automatically operating cable trash rack cleaner with tipper trolleys for transporting away the material caught in the trash rack was put out to tender. The tipper trucks are moved to the temporary waste disposal site with a residual diesel engine and hydraulically tipped out there. At the start of the project, due to the advantages when handling bulky and large floating debris, a design as a dredger trash rack cleaner was considered. With a dredger trash rack cleaner, it is possible for large tree trunks to be picked up by the gripper rake and for carpets of floating debris to be pushed towards the weir before the trash rack. Another advantage of the dredger machine is the possibility to be able to dredge free any silting up of the base of the trash rack. However, this advantage was also offset by a number of disadvantages. For instance, with the dredger concept it was not possible to maintain the short cleaning cycles which are required. Moreover, due to the large amount of space required compared with a cable machine, a dredger machine would have been difficult to incorporate into the existing structure of the facility. Cleaning of trapped objects from the spaces between the teeth by means of a toothed strip is also only possible with a cable trash rack cleaner. Ultimately, after weighing up the advantages and disadvantages, the cable trash rack cleaner was preferred after all.

photo credits: Urbas

by Reinhold Gracner DI (FH) [URBAS]


photo credits: Urbas

photo credits: Urbas

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Hollersbach power plant: fixed and tiltable cable trash rack cleaner

The cable trash rack cleaner in Neuรถtting has what is known as an "aggressive wooden rake" with the rake itself weighing four tonnes. This high weight of the rake results in cable forces of up to 20 tonnes and driving power of 37 kW being required from the cable drum. URBAS Maschinenfabrik GmbH was entrusted to implement this. From the first draft design through to commissioning, everything comes from the medium-sized company from the town of Vรถlkermarkt in the Austrian state of Carinthia. In addition to the price quoted, the customer was won over primarily by the large number of reference plants which URBAS has delivered and implemented over the last 30 years.

EON WASSERKRAFT GMBH REPLACES THE CABLE TRASH RACK CLEANER IN NIEDERAICHBACH E.ON Wasserkraft GmbH, which is based in the town of Landshut, operates 110 proprietary and managed power plants on the Danube, Inn, Isar, Main, Lech, Eder and Diemel rivers and, with an operator capacity of over 2,100 megawatts, it is one of the largest producers of renewable energies in Germany. The plant in Niederaichbach was commissioned in 1948 and has a plant power output of 16.1 MW. Located directly upstream of the hydroelectric power plant is the Isar 1 nuclear power plant. This was disconnected from the grid on 17 March 2011 as part of the shutdown of a total of eight nuclear power plants in Germany and it is currently idle. As up until this point in time a considerable proportion of the headwater was used for cooling the nuclear power plant and was therefore precleaned, after the shutdown the amount of

Gailitz power plant: stationary trash rack cleaner

work for the trash rack cleaner at the Niederaichbach hydroelectric power plant changed considerably. As no spare parts were available for the heavily worn cable drum and for the gearbox for the cable machine, which was over 60 years old, the electrics were already very out of date and the amount of manpower required to maintain its operation was becoming ever greater, the people in charge decided to replace it with a new state-of-theart machine. URBAS Maschinenfabrik GmbH was commissioned to deliver this powerful cable trash rack cleaner. The machine is designed with a heavy wooden rake and it also equipped with an integrated bulkhead lifting device and a loading crane with a gripper claw. This is used to pick up larger tree trunks located in the immediate vicinity of the trashrack. In this case, the material caught in the trashrack is transported away via a moveable trough chain conveyor. Further machines for Verbund Innkraftwerke GmbH (Feldkirchen power plant) for E.ON Wasserkraft (Dingolfing power plant) and for Ennskraftwerke GmbH (Staning)are planned for next year.

ROBUST HORIZONTAL TRASH RACK CLEANER FOR NIKLASDORF Niklasdorf Energie- und Liegenschaftsverwaltungs GesmbH operates the Niklasdorf plant 1 power plant on the River Mur at Niklasdorf in the Austrian state of Styria. As part of a complete revitalisation, the existing Niklasdorf plant I power plant facility is being optimised from both an economic and ecological point of view. Among other things, the existing trashrack structure leading to the works water channel is being replaced with a new horizontal trash rack including a trash rack cleaner.

The trash rack is cleaned by stripping off the fine trash rack which is arranged at an angle to the main direction of flow via a vertical rake. The cleaning process is aided here by the natural flow of the water current in the direction of the grill bars and a weir flap arranged downstream. The advantage of such a trash rack cleaner compared with conventional cable and dredger trash rack cleaners is obvious. The floating debris is not removed from the water and does not therefore need to be disposed of subsequently at great cost. A loading crane with a wooden gripper claw situated on the powerhouse ensures that any debris in the water can be removed in front of the trash rack. An assembly basket for two people is fitted on the loading crane to allow maintenance work to be carried out on the trashrack. The horizontal cleaning machine is supplied by URBAS Maschinenfabrik GmbH. The installation and commissioning has taken place in the autumn of 2012. The aspects of the URBAS concept which particularly persuaded the customer were the solid mechanical engineering and the very good operational experience from the reference plant in Hieflau.

METICULOUS PLANNING RIGHT DOWN TO THE FINEST DETAIL Nothing can be left to chance when it comes to the success and safety of the facilities. Extensive investigations carried out prior to the start of construction ensure that there are no unpleasant surprises on the construction site. They lead to dissatisfaction and cost a great deal of time and money. Lots of factors need to be taken into account here in order in the end to supply a trash rack cleaner which keeps the inflows clear absoluApril 2013

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photo credits: Urbas

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Hieflau power plant: One of the world's largest horizontal trash rack cleaners with a rake length of around 8 m and a cleaning force of 15 kN.

tely reliably and efficiently. The facility is planned right down to the finest detail on a modern 3D CAD system. This ensures that there are no collisions between components. The frame structures are designed and optimised using professional rod statics software. The component stresses and the deformations on the machine components which are subjected to high loads are also calculated via a finite element program. Based on the results of the calculations, the components are shaped in a flux-optimised way. The motto here

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Neuรถtting power plant: Static of the frame structure

is also to obtain everything from one source. All calculations are carried out by the engineers working for the company URBAS.

MANUFACTURING AT THE HIGHEST LEVEL The fabrication and installation of hydraulic steel components in general and of trash rack cleaning facilities in particular require exacting quality standards from employees, materials and the level of workmanship. URBAS Maschinenfabrik GmbH from the town of Vรถlkermarkt in the Austrian state of

Carinthia with around 80 employees, 250 workers and 35 apprentices at the manufacturing site near Ruden is one of the first businesses anywhere in Austria to be certified to EN 1090-1/-2; EXC 4 and this therefore ensures manufacturing at the very highest level. From the welding workshop and machining right through to the paintshop, URBAS Maschinenfabrik GmbH has all of the facilities that are required to manufacture the hydraulic steel components.

zek HYDRO 2013  

International magazine for hydro power and future technology http://hydroint.zek.at/

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