zek HYDRO 2025

MAGAZINE FOR HYDROPOWER

Green energy on the Kentucky River

Strong comeback of a traditional company

Weir renovation for World Heritage power plant

New technologies for wear and cavitation protection

Your Innovator for Maximum Performance. Digital Solutions

www.global-hydro.eu

INNOVATIVE TECHNOLOGIES AS CATALYSTS FOR THE

TRANSITION TO SUSTAINABLE ENERGY PRODUCTION

TRoland Gruber Editor-in-Chief | rg@zek.at

he media’s response was rather weak and restrained. Only a few publications even considered it worth a headline: as of the beginning of this year, the global average temperature has exceeded the 1.5 °C mark. That’s the mark that was established at the Paris Climate Conference in 2015, as agreed to by the representatives of 195 countries. This means we are talking about a historical event of the deplorable kind, with incalculable consequences. However, resignation or defeatism are not an option. After all, this crucial development has the potential of accelerating the efforts of the growing climate tech industry. As Jan Lozek, the founder of Future Energy Ventures, recently pointed out with decided optimism, “Crossing that 1.5-degree threshold might, paradoxically, turn out to be just the kind of catalytic event the climate tech industry needs right now. That’s because it highlights the urgency for further investments in climate technologies and opens up new markets for adaptive solutions.” In this respect, Lozek shares an opinion voiced by many other energy experts in the field: AI may well turn out to be the key to the ‘energy turnaround’, as it is already emerging as a major factor in integrating and optimising decentralised energy sources, ready to boost the overall efficiency of our electricity grids. A successful transformation of the energy supply system also depends on modern high-capacity grid structures – and increasingly on AI-driven controls capable of adjusting automatically to the behavioural patterns of providers and consumers alike. In all of this, research and development play a central role, as does the systematic knowledge transfer between the fields of research and its practical application. The technical solutions that will lead us towards a post-fossil future of energy are opening up vast economic opportunities – especially considering Europe’s extensive technical competence in the energy sector. At any rate, one thing is clear: by far the greatest growth potential within the energy sector lies in renewable sources. The current World Energy Outlook expects the share of energy from renewables to grow from 30 per cent (as of 2023) to 83 per cent by 2050. For Europe, the projected share is even 84 per cent. In the long run, photovoltaics and wind power may well be the main drivers of growth across the industry. However, hydropower will remain an indispensable player where sustainable energy production is concerned – especially in Central Europe. Today, this aspect is more important than ever, considering the vehemence and sometimes patently false or outdated arguments raised by hydropower opposers in many media channels. Hydropower is anything but a relic from a distant past. On the contrary, hydropower is being under constant further development by innovative providers, universities and other research institutions. With the resulting latest advancements in digital research raising the achievable level of performance, hydropower will continue to be an indispensable factor in ensuring a reliable supply of electrical energy. This was also confirmed in recent study put out by the Energy Watch Group, which called for a serious re-evaluation of hydropower’s frequently distorted public image. According to the study, modern re-powering efforts can be shown to help ensure a sustainable hydro-ecology and diversity of species. As the authors point out, the decline of the fish population is caused primarily by environmental toxins and high-levels of methane from agricultural sources. The study further shows that hydropower facilities are essential contributors to the removal of plastic waste and noxious biomass from the rivers. In a further conclusion the authors confirm that hydropower contributes crucially to grid stability. Moreover, the study also investigated the vehement call by several organisations for a “renaturation” of existing transverse structures. In fact, if this is done while maintaining the straightened course of a river, it will accelerate the velocity of flow, This, in turn, will deepen the water bed, thus lowering the subterranean water levels in the area around river banks and water meadows. It’s a classic example of “improving things for the worse”. Taken together, these arguments should provide more than sufficient reasons for government to ramp up their efforts towards more – and more sustainable – support for the (smallscale as well as large-scale) hydropower industry.

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]

Hydropower. Complete solutions for a sustainable future.

Reliability beyond tomorrow.

PROJECTS

06 Table of contents

SHORTCUTS

08 Short news out of the world of hydropower

09 Masthead POLITICS

16 Advancing the role of small hydropower in Europe Comment by EREF

PROJECTS

18 Rejuvenated control technology for Southern German SHPP [Germany]

22 Flagship project – green energy on the Kentucky River [USA]

25 Austrian experts supply hydropower technology to the far east [Taiwan]

EVENT

28 The entire world of hydropower united for three days in Graz HYDRO 2024

PROJECTS

30 Industry professionals multiply power plant output in South Tyrol [Italy]

INDUSTRY

34 Back to its best – impressive come back of a traditional company Generators

38 Highly specialized in mechanical installation: CMA Hydro Presentation

PROJECTS

40 New hydropower plant on the Mur supplies 15,000 housholds [Austria]

INDUSTRY

44 AUMA celebrates 60 years of success Anniversary

TECHNOLOGY

45 New technologies for wear and cavitation protection Shielding Turbines

PROJECTS

50 Renovation for bottom outlet of World Heritage power plant [Germany]

55 New small-scale hydropower plant in Valle d‘Aosta goes online [Italy]

PROJECTS

58 Happy ending to Albanian power plant in need of renovation [Albania]

62 Ossberger turbine produces green electricity at Whiteadder Reservoir [Scotland]

INDUSTRY

64 PELFA demonstrates large-hydro power manufacturing competence Presentation

66 Repower celebrated its 120th anniversary History

PROJECTS

67 Impressive innovative technology at new residual hydro power plant [Austria]

EVENT

70 Hydropower as the key to the energy transition Viennahydro 24

TECHNOLOGY

72 Setting new standards with the first horizontal 6-nozzle-Pelton turbine Turbines

PERMISSION GRANTED FOR NEW TRAUNFALL HYDROPOWER PLANT

The Supervisory Board of Energie AG Oberösterreich has given the go-ahead to the construction of a new run-of-river power plant at the Traunfall site. Energie AG‘s third-largest power plant on the River Traun is to be built at a cost of around 190 million euros to provide clean energy for around 35,000 households. The new plant will replace the existing Gschröff, Siebenbrunn and Traunfall power plants, each of which has reached the end of its working life. The original plants were built in 1888. The new one is to be a conventional water diversion power plant with construction scheduled to start in the summer of 2025. Preliminary work is to begin immediately and building is expected to take around three years. Operation trials for the new Traunfall power plant are scheduled for 2028. .

90 YEARS TROYER: THE LONG WAY TO BECOMING A GLOBAL PLAYER

Troyer is a South Tyrolean hydropower specialist and is celebrating 90 years in business. In Fall 2024 employees, customers and partners gathered for lively festivities at the headquarters in Vipiteno – as they looked back on the company’s impressive history. What began in 1934 as a small workshop with five employees, has developed into an international player of global renown with 120 employees. It is a success story, which is based on ingenuity and technical brilliance, but also on values such as perseverance, tenacity, family cohesion and South Tyrolean diligence. Troyer is now one of the world‘s leading suppliers of hydropower systems. In keeping with the occasion, the event also looked toward the future. Prospects and potential for sustainable energy solutions were discussed – alongside Troyer‘s role as a pioneer of the energy transition.

SLOVAKIA‘S LARGEST HYDROPOWER PLANT TO BE MODERNIZED

As reported by Slovakian broadcaster STVR, Slovakia‘s largest hydropower plant, Čierny Váh in the Low Tatras, is to undergo extensive modernization. The 40-year-old turbines of the pumped storage power plant are to be replaced in stages. The first of the seven turbines has already been modernized in 2024, with the others to follow. A key problem is the fluctuations in electricity generation from solar power plants, which are dependent on the weather. „On sunny days, when electricity prices fall and it is necessary to ensure grid stability by drawing power, pumped storage power plants start pumping,“ explains Milan Ilčík, Director of Hydropower Plants at Slovenské elektrárne. According to the company, the modernization and construction of the battery storage facility will cost several hundred million euros.

CROSSFLOW TURBINE ENSURES POWER SUPPLY SELF-SUFFICIENCY

In October 2024, Ossberger – the southern German hydropower specialists – completed a ‘lighthouse’ green energy project in north-western Uganda, involving the renewal of a small hydropower plant in order to secure the power supply to Kuluva Hospital. The heart of the plant is a highly reliable crossflow turbine supplied by Ossberger. The turbine allows the hospital to benefit from its design strengths across a wide partial load range. Modernisation of the plant also involved replacement of the electrical infrastructure and control equipment with new technology also supplied by Ossberger. The power plant has already been recommissioned, so from now on the hospital will be self-sufficient as regards its power supply. Plant renewal commenced in November 2022 and was completed in just under two years.

With an investment volume of around 190 million Euro, Energie AG‘s third-largest power plant is being built on the river Traun.

With an average electricity production of 200 GWh, the Čierny Váh power plant is the most powerful hydropower plant in Slovakia.

Kuluva Hospital in Uganda is guaranteed a reliable power supply for the future thanks to its new Ossberger crossflow turbine.

Davide Sartori, Stefan Troyer, Davide Albani and Philipp Schenk from the Board of Directors, and HTI CEO Anton Seeber cutting the cake.

© Energie AG

© Troyer

Kuluva Hospital

POWER PLANT EQUIPPED WITH MODERN TECHNOLOGY

Last year, the Swiss energy supplier Repower AG carried out a comprehensive modernisation project to ensure the Ferrera power plant in Grisons was fit for the future. The plant is owned by Ovra electrica Ferrera SA, 51% of which is owned by the municipality of Trun and 49% by Repower. Basically, with the exception of structures and the penstock, the plant’s entire technical infrastructure was renewed or revitalised. In the power plant control centre, the 2-nozzle Pelton turbine and the directly-coupled synchronous generator underwent a retrofitting programme. There was a complete redesign of all the electrical and control equipment that had caused repeated malfunctions and operational failures in the past. Various hydraulic steelwork components and the shut-off and regulating devices at the water intake were also modernised or refurbished. The Grisons power plant has an average output capacity of 17.6 GWh and comprehensive modernisation has ensured the plant is ideally equipped for the decades ahead. Around CHF 2.7 million was invested in the modernisation of the plant.

ANDRITZ MODERNISES NORWAY’S VAMMA HPP

Vamma, Norway‘s largest run-of-river power plant, is to be upgraded. Hafslund is a Norwegian utility company and has commissioned the international technology Group ANDRITZ to modernise one of the power plant‘s machine sets. The output and efficiency of Vamma‘s Unit 11 is to be increased to bolster the power plant‘s role as a key pillar of Norway‘s renewable energy offering. The project will increase the installed machine output by 22% – from 100 MW to 122 MW. The scope of delivery includes dismantling, reassembly, testing and commissioning, as well as model tests and the supply of new components. It also guarantees the provision of a new, oil-free Kaplan turbine with a water-filled hub. This will not only improve efficiency, but will enhance the degree of ecological sustainability offered by the power plant. At a diameter of 7,300 mm it will be one of the largest Kaplan turbines in Norway. ANDRITZ will also provide a new turbine governor and a stator to be installed on site. Commissioning is scheduled for 2028.

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Produziert nach den Richtlinien des Österreichischen Umweltzeichens, Druckerei Roser GmbH, UW-Nr. 1037

The Vamma hydropower plant is owned by Hafslund and equipped with twelve machine sets. It has a total installed capacity of 343 MW.

The Ferrera power plant in Switzerland underwent a thorough modernisation. It has an average output capacity of 17.6 GWh.

CHINA PLANS RECORD HYDROPOWER PLANT IN TIBET

China is planning the world‘s largest hydropower dam in Tibet: a mega-project that could generate 300 billion kilowatt hours of electricity per year. According to reports from the German “Focus Online”, the hydropower plant is to be built on the Yarlung Tsangpo. The Chinese government has already given the green light for the monumental dam in the remote Tibetan mountain region. The Yarlung Tsangpo in the imposing mountain world of Tibet offers ideal conditions for a mega power plant. The river has an altitude difference of around 2000 meters over 50 kilometers, which promises enormous energy potential. The dimensions are record-breaking. The previous record holder, the Three Gorges Dam, produces just 88 billion kilowatt hours – not even a third of the planned output. However, the construction challenges are considered to be enormous. This is because the region is extremely remote - the first paved road was only completed in 2013. The estimated costs are the equivalent of around 135 billion euros.

SUCCESSFUL PREMIERE FOR HYDROPOWER SPECIALISTS IN ZIMBABWE

Great Zimbabwe is a new small-scale hydropower plant in Zimbabwe, Africa, and began generating clean electricity for the first time in November 2024. The entire range of electromechanical and I&C equipment here was supplied by the Austrian hydropower specialists at GUGLER Water Turbines GmbH. The Austrian hydropower experts had already successfully completed a whole series of projects in Africa. This project was the first opportunity for GUGLER to demonstrate its expertise in Zimbabwe, a country with a population of around 15 million people. The power plant is located at the foot of the Mutirikwi dam and utilises the water released from the reservoir for irrigation. The centrepieces of the power plant are two identical Francis turbines supplied by GUGLER. Together they generate a bottleneck output of 5.4MW. In addition to stabilising the energy availability of the national grid, the new green power plant is expected to reduce CO2 emissions by 11,100 tons per year to contribute to Zimbabwe‘s transition to a sustainable energy future. According to the lowcarbonpower.org website, 55% of Zimbabwe‘s electricity needs in 2022 were covered by hydropower.

The Yarlung Tsangpo flows directly on the border with India and later becomes the Brahmaputra.

The Great Zimbabwe power plant uses the hydroenergetic potential of the Mutirikwi reservoir to produce green electricity.

©

© Gugler

NEW LARGE-SCALE POWER PLANT IN UGANDA

Uganda commissioned its largest power generation facility at the end of September 2024. The 600-MW power plant on the Nile River cost $1.7 billion and according to a report by marketscreener.com it was financed with a Chinese loan. The Karuma Hydropower Project, built by the Sinohydro Corporation, increases Uganda‘s power generation capacity to just over 2,000 MW. At the commissioning ceremony in Kiryandogo in northern Uganda, Zhang Lizhong – the Chinese Ambassador, spoke of the power plant as a “showcase project for cooperation between China and Uganda.” Uganda exports electricity to the neighboring countries of Rwanda, Tanzania and Kenya, so to transport the electricity a 400-kV, 248-kilometre transmission line was also inaugurated as part of the commissioning process. Karuma is the second Ugandan hydropower plant China has financed in in recent years.

Fabrication of Kaplan runner Complete assembly, ready for erection

FIRST VERY-LOW-HEAD TURBINE IN SWITZERLAND

At the end of September 2024, Forces Motrices de MartignyBourg (FMMB) officially commissioned the first Swiss low-pressure VLH-type (Very Low Head) turbine. The new turbine was installed in the underwater channel of the river at the MartignyBourg power plant to produce around 850,000kWh of electricity per year – covering the average annual consumption of almost 200 households. Now, the hydropower available at the site has been optimised without placing any additional burden on the environment. “Installation of the new low-pressure turbine enables us to make the best possible use of the available water resources – in an environmentally-friendly manner. The project demonstrates our commitment to sustainable innovation and the energy transition,” states Georges-Alain Zuber, head of the Martigny-Bourg power plant. The VLH turbine can process up to 10.2m³/s and is designed for a head of 2.0 to 2.5 metres.

process of Kaplan blade and finish Pelton runner different dimensions till 4,5 diameter

and finish assembly injectors ready for erection

runners fabricated in forge and welding process in three parts

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The Karuma hydropower project on the Nile will increase Uganda‘s generation capacity by more than 2,000 MW.

The first VLH turbine in Switzerland can generate approximately 850,000 kWh of green electricity in a standard year.

KOEHLER GROUP ACQUIRES SCOTTISH POWER PLANT

Koehler Renewable Energy continues to expand in the field of power plant development with the aim of generating sustainable energy. On November 1, 2024, it acquired Pitnacree hydropower plant in Scotland, completing the acquisition through its UK subsidiary. Pitnacree hydroelectric power station is located on the Pitnacree Estate, Ballinluig, near Pitlochry, Scotland. It was developed and built by the estate owners and has been an important part of the region‘s renewable energy infrastructure since it was commissioned in December 2015. An installed capacity of 300 kW and high efficiency (82%) for a maximum water flow of 236 l/s enable the hydropower plant to guarantee a reliable supply of energy.

AUSTRIAN KNOW-HOW FOR KYRGYZSTAN

The Austrian Federal President Alexander Van der Bellen received his Kyrgyz counterpart Sadyr Japarov with military honours in the capital city, Vienna, on 25 November 2024. The two heads of state discussed geopolitical issues in a private face-to-face discussion before a further working meeting was held, after which six memorandums of understanding were exchanged to facilitate an intensification of cooperation between Austria and Kyrgyzstan. The Austrian Ministry of Finance and the respective Kyrgyz ministries agreed to cooperate on digitalisation, business, innovative technologies and mining. Andritz Hydro GmbH signed a memorandum of understanding with the Kyrgyz Republic Ministry of Energy to intensify cooperation in the expansion of hydropower capacities in Kyrgyzstan.

TB.GLARUS COMMISSIONS LARGE-SCALE BATTERY

Technische Betriebe Glarus (tb.glarus) has made a very public step toward the energy transition with a new large-scale battery in the village Netstal. The plant now optimises electricity utilisation in the region with an output of 10.4 MW and a storage capacity of 12.3 MWh, complementing the existing hydropower infrastructure excellently. Of particular note is that the plant battery now supplies 10% of the battery storage system’s share of balancing energy required for Switzerland, thus making a decisive contribution to grid stability. Once the intensive test phase had been completed, the system was officially put into regular operation in February 2025.

Koehler Renewable Energy acquired the Pitnacree hydropower plant in Scotland on November 1, 2024.

Kyrgyz President Sadyr Japarov (left) is received by his Austrian counterpart Alexander Van der Bellen.

Martin Winteler, Project Manager tb.glarus, between the lined-up battery elements of the new large-scale battery in Netstal.

© Koehler Group

CANADIAN PROVINCES SIGN NEW AGREEMENT

In mid-December 2024, Eulerpool News reported that the Canadian province of Newfoundland and Labrador had signed a landmark memorandum of understanding with the neighbouring province of Quebec to fundamentally reshape hydropower generation in Labrador. The new deal is expected to generate an estimated 200 billion Canadian dollars by 2075, and replaces the controversial 1969 agreement that previously governed electricity exports from the Churchill Falls plant – and caused decades of tension between the provinces. Although the majority of the plant is under Newfoundland and Labrador ownership, most of the revenue had flowed to Quebec due to its legal entitlement to purchase electricity at fixed and extremely low prices – and to resell it to the US at profitable margins. The premiers of both provinces see the new agreement as a win-win solution.

PARTNERSHIP AGREED FOR HYDROPOWER EXPANSION

Tata Power Company Limited of India and Druk Green Power Corporation Limited of Bhutan have forged a regional partnership and are collaborating to generate 5,000 MW with clean energy projects. In line with Bhutan‘s vision for its energy sector, the partnership aims to increase the country’s total generation capacity to 25,000 MW by 2040 – thereby guaranteeing energy availability and regional energy integration. To achieve this goal, Bhutan is diversifying its energy portfolio beyond traditional hydropower to include solar and geothermal energy. The collaboration projects will generate at least 5,000 MW of renewable energy, including 4,500 MW of hydropower from the 1,125-MW Dorjilung HEP project, the 740-MW Gongri Reservoir, the 1,800-MW Jeri Pumped-Storage Power Plant and the 364-MW Chamkharchhu IV plant – all to be developed jointly in several phases.

LARGE PENSTOCK FOR BALTIC POWER PLANT

Bilfinger, the industrial services provider, is assisting the energy company Ignitis Gamyba as it expands Lithuania’s Kruonis pumped storage power plant. The contract is being implemented in cooperation with the Voith technology group, and the aim is to enhance Lithuania’s green power capacity and its energy independence. Although originally planned as an eight-pump-turbine plant, only four 225-MW-capacity turbines actually went into operation upon completion in 1992. Voith Hydro is to supply a new fifth pump turbine, while Bilfinger will be bearing responsibility for the construction of a new exposed penstock to connect the power plant’s upper basin with its lower basin and the pump turbine. A team from Bilfinger Industrial Services Austria will be responsible for implementing the approximately 900-metre, 5,285-mm diameter exposed penstock along the entire value chain – including engineering, manufacturing, transport, installation, corrosion protection and commissioning.

Machine room at Canada’s Churchill Falls power plant

Headwater view of Kruonis pumped storage power plant – the only one of its kind in the Baltic region.

The partnership between Tata Power and Druk Green Power aims to expand hydropower generation capacity in Bhutan significantly.

When there is a surplus of electricity, water is pumped from the lower basin to the upper basin.

© Druk Green Power

© Ignitis Gamyba

© Ignitis Gamyba

© Wikimedia /Martin Lopatka

DIGITAL FUTURE

AUMA RETROFIT

Discover our service portofolio

Neckarwerk has been generating electricity since 1911. Originally it provided for the city‘s entire electricity needs, and today still powers around 600 households.

NEW TRASH RACK AT NECKARWERK PLANT

After 30 years of service, the rake screens at the Neckarwerk plant in Tübingen had reached the end of their useful life and required complete replacement. Stadtwerke Tübingen installed a needle weir, drained the intake and sealed the entire system before work began in June 2024. The new trash rack cleaners protect the turbines from leaves and branches. Whereas the original technology moved floating debris into a container, it is now fed straight back into the river. This is more ecologically sound and reduces cleaning time from five to two minutes. Consequently, more water flows into the turbines, thus increasing the power output of the hydropower plant. Stadtwerke Tübingen completed this key modernisation step at the end of February 2025.

NEW MANAGING DIRECTOR AT VOITH HYDRO

As of April 1st, 2025, Jan Lüder has been CEO at Voith Hydro and a member of the Corporate Board of Management within the Voith Group. Succeeding Tobias Keitel, Jan Lüder was most recently Division President at Sulzer AG in Switzerland. Between 2015 and 2022 he held management positions at ThyssenKrupp, and for almost 20 years from 1995 to 2015 he worked for Siemens AG in the Metals Technologies, Industrial Solutions and Power Generation divisions, holding international management functions in Asia (China, Malaysia) and Europe (Germany, Finland, Austria). Jan Lüder has a degree in electrical engineering from the Technical University of Berlin.

Jan Lüder takes over from Tobias Keitel as the new Managing Director of Voith Hydro.

© swt/Schwermaul/Marquardt

© Voith

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ADVANCING THE ROLE OF SMALL HYDROPOWER IN EUROPE

Ursula Von der Leyen’s first mandate as President of the European Commission was defined by the European Green Deal, a comprehensive strategy to drive the EU towards climate neutrality and sustainability. In her second mandate, the focus shifted to its successor, the Clean Industrial Deal, which seeks to merge the goals of decarbonisation and competitiveness into a cohesive growth strategy. Released in late-February 2025, the Clean Industrial Deal outlines plans to, among others, improve energy affordability, mobilise investments in renewable energy, and restore Europe’s industrial strength and leadership in the climate transition.

Parallel to these new EU initiatives and legislation developments, national governments of EU Member States need to transpose recent EU legislation under the Green Deal into national law. It needs to be highlighted that most of this European legislation such as the revised Renewable Energy Directive (RED III) can be used to promote hydropower. Yet, the final decision and the extent lies in the responsibility of EU Member States.

Member States should use all possibilities under RED III to promote hydropower

Despite the new wording “Clean Industrial Deal”, the European Commission regards the further development of renewable energy (and energy efficiency) as an important tool to enable Europe’s energy independence and to supply cheap energy.

The amended Renewable Energy Directive (RED III) plays a pivotal in this. However, despite these efforts and opportunities for Member States, significant challenges persist for (small) hydropower developers. These include delayed RED III transposition, the continuous need for extensive environmental impact assessments, and a lack of political will to use the opportunities and benefits of small hydropower projects. Even with the recognition of renewable energies as being of overriding public interest, many hydropower stakeholders have expressed frustration over the persistent administrative and legislative hurdles. This issue is particularly evident with the exclusion of hydropower from so-called Renewable Acceleration Areas (RAAs), which would allow for fast-tracked permitting processes and a reduction of legislative procedures. It is time for national governments to use the possibilities provided by the relevant EU legislation for the hydropower sector.

Small hydropower’s opportunities for storage

Recognising (small) hydropower as an important source of renewable energy is essential, given its ability to contribute to flexibility, energy storage, and congestion management. These advantages make small hydropower a key player to enable the integration of more volatile renewable energy sources, such as photovoltaic and wind, while contributing to the decentralisation and stability of the grid system.

Parallel to ideas of the European Commission to update its recommendation on energy storage (C/2023/1729), project developers and decision-makers look into the possibilities for small and medium-sized pumped storage power stations to improve regional new energy consumption capacity.

EREF and its working groups are in the process of developing recommendations for decision-makers and to provide bestpractice examples.

Implementation of the Nature Restoration Regulation

Parallel to the designation of Renewable Acceleration Areas (RAAs) in EU Member States under RED III, governments are also tasked with the development of national restoration plans (NRP) until the beginning of September 2026 due to the implementation of the Nature Restoration Regulation (NRR).

The Regulation entered into force across all Member States on the 18th of August 2024. It sets legally binding targets to restore 20% of the EU degraded land and sea ecosystem by 2030, and all ecosystems in need by 2050. To achieve these objectives, Member States must restore at least 30% of habitats covered by the NRR from poor to good condition by 2030 – 60% by 2040 and 90% by 2050. Priority is hereby given to areas located in

EREF clarifies that it is time for the EU to recognise hydropower’s role in contributing to climate adaptation.

Natura 2000 sites. Among others, the regulation foresees the restoration of 25,000 km of river ecosystems by 2030. Governments need to identify in their national restoration plans restoration areas and list measures how they want to improve habitats and river ecosystems over the next two decades. EU Member States shall ensure synergies with the new Renewable Energy Directive and coordinate their national restoration plans with the mapping of areas necessary for the national contribution towards the Union´s renewable energy target of at least 42,5% by 2030.

The obligation for Member States to prevent deterioration of the ecosystem does not apply to deterioration caused by renewable energy projects, their connection to the grid and the related grid itself as well as storage assets outside Natura 2000 sites. This also applies to hydropower.

The European Commission is in the process of providing assistance to national governments on how to best develop such plans. An Implementation Regulation is planned for the coming weeks followed by an explanatory brochure and an online Reference Portal which includes necessary resources.

New methodology to establish free-flowing rivers

One of the key goals of the Regulation is the establishment of 25,000 km of so-called free flowing rivers. The Water Framework Directive provides already a definition of ecological continuity of rivers as a key biological supporting element. Yet, under the process of the Common Implementation Strategy (CIS) under the Water Framework Directive (WFD), the Commission, in consultation with governments and stakeholders including EREF and its members, develops a new methodology to establish free-flowing rivers by testing case studies of different river types across Europe.

Once finalised in autumn 2025, the Commission plans to use this new methodology for the implementation of the Nature Restoration Regulation. Intentions to publish the free-flowing rivers methodology as CIS guidance documents reflects the position of the Commission on the interpretation to give to the

Despite REDIII and other opportunities for EU-Member States, significant challenges persist for (small) hydropower developers.

definition of “free-flowing rivers” given in article 3 of the Nature Restoration Regulation.

Parallel to that, the Commission plans for 2025 the collection of national cases on specifications and implementation of environmental flows to identify best practices and measures. A first discussion document on the basis of the first reported cases and a stakeholder workshop on environmental flows best practices are planned towards the end of 2025. A final report and recommendations are foreseen for the end of 2026.

EREF and its members will again provide best-practice examples and recommendations from the small hydropower sector. Among others, EREF leads the working group on biodiversity of the ETIP Hydropower project and collects insights from hydropower stakeholders and experts on these issues. The resulting White Papers will be submitted to the European Commission and Parliament, addressing the policy and legislative changes needed to expedite hydropower deployment across Europe. Europe’s (small) hydropower sector demonstrates that electricity production and the ecological status of a river can go hand in hand harmoniously. Hydropower projects have advanced technologies and best management practices to promote the ecological status of rivers, such as fish passage systems, specialised turbines, and compromises between river flow and energy production needs.

Model project in Norway

For example, at the Hafslund-Hunderfossen plant on the Gudbrandsdalslågen river in Norway, a series of innovative measures were introduced in 2023, leading to record-breaking levels of fish migration since the dam’s construction. These included optimised gate systems designed to improve fish migration, and the installation of novel automatic fish counters on fish ladders. Such measures underline the commitment of the hydropower sector to integrate eco-friendly measures into renewable energy production. It is also important to mention that small hydropower plants can lead to new and rare habitats for aquatic life, serving to improve their overall ecological status. EREF calls on national governments to implement the Nature Restoration Regulation in a way that does not cause burdens to hydropower producers. EREF continues highlighting best practice examples and exploring other measures for the implementation of these directives to ensure that the role of small hydropower in Europe’s energy transition is not overlooked.

European Water Resilience Strategy

To better adapt to more frequent weather extremes such as floods and droughts due to climate change, the European Commission is developing a European Water Resilience Strategy. It aims to ensure clean and sufficient water for all, to protect ecosystems, and to strengthen Europe’s economy through sustainable water management.

EREF highlights the benefits of (small) hydropower for water resilience and climate adaptation. In addition to production of renewable electricity, hydropower supports the mitigation of water scarcity and prevention of floods by leveraging their water storage and regulating water flows. Ensuring these services, however, often entails additional costs for power plants. EREF therefore calls on European decision-makers to recognise hydropower‘s dual role in energy production and water resource management. It is time for the EU to recognise hydropower’s role in contributing to climate adaptation and for individual Member States to ensure proper remuneration.

REJUVENATED CONTROL

TECHNOLOGY BRINGS SOUTHERN GERMAN SMALL-SCALE

POWER STATIONS UP TO CURRENT STATE OF TECHNOLOGY

It was high time to take action. The control equipment in some of the 17 small-scale power stations owned by energy provider naturenergie was falling well below current standards for water power utilisation. To remedy the situation, the operator initiated the modernisation of the control systems in six of their facilities. The contract for the project was awarded to South Tyrolean hydropower all-rounder Troyer. From 2022 to 2024 Troyer’s engineers proceeded to bring the facilities up to the latest technical standard, all to the full satisfaction of the operator. Further projects to modernise existing control systems are already in the pipeline.

When it comes to hydropower technology, longevity is key. Turbines, hydraulic steelwork constructions or penstocks, if implemented by well­established industry providers, will typically last for decades. Unfortunately, the same does not apply to a specific component that modern facilities simply can’t do without: the control system, especially the operating software. Yesterday’s high­end (or at least state­of­the­art) solution may already be outdated or even obsolete by tomorrow. “The typical lifespan quoted for control system components is about 30 years,” says Tobia Walpoth, who heads up Troyer’s Automation department. “But that applies only to the PLC and the control panels, not the software. In fact, the operating software is increasingly short­lived.” Tobia Walpoth knows what he is talking about. Over the past few years, he and his team have equipped numerous hydropower stations with latest­generation control equipment. For many years Troyer’s control solutions have ranked among the most advanced technologies the European hydropower industry has to offer. In a recent demonstration of their competence, the South Tyrolean

experts modernised a series of power facilities in Germany’s Black Forest region.

A colourful mix of control systems

The group of small­scale hydropower stations operated by naturenergie hochrhein AG comprises a total of 17 facilities. naturenergie owns them all, except for three, which they operate on behalf of third­party providers. In many respects the power stations, which are situated at various locations throughout the Black Forest region, could hardly be more diverse, as Tim Schöne, naturenergie hochrhein’s team leader for small­scale power stations, explains: “It’s definitely a colourful bunch. Some of the facilities are around 100 years old and have always belonged to our company. Some are part of old industrial works, but there are some new ones as well. The forebay configurations are also wildly dissimilar. As for the control systems, there was a whole pot­pourri of designs and formats to deal with. It’s been a growing challenge for our team in recent years.” The consequences, as Schöne points out, include rising maintenance and

Hydropower station Hottingen was equipped by Troyer some ten years ago. Six additional power stations have now received an upgrade of their control and automation systems.

storage costs, extremely limited remote access options, and problems finding replacement parts for some of the systems. “In some cases the manufacturers stopped selling replacement parts ten years ago. It took a lot of creativity and improvisation effort to keep the facilities operating at least on a somewhat economical level.” Faced with these challenges, the operators decided to first modernise and unify the control equipment in five of their own facilities and, pending the owner’s go­ahead, in one of the third­party owned ones. In 2020, they launched an EU­wide invitation to tender for “Project Standardisation of Control and Electrical Equipment”, with eminent South Tyrolean hydropower all­rounder Troyer eventually winning the contract as the best bidder.

New technology for six power stations

Troyer was not exactly unknown to the experienced hydropower operators from Southern Germany. In 2015 and 2016, the South Tyrolean specialists had already provided the entire equipment for two of the newer power stations, i.e. the facilities in Mambach and Hottingen. The components installed at that time included everything from the electromechanical componentry to the control system. Collaborating on this project, as Tim Schöne recalls, was an excellent experience. In 2022, the Troyer team set to work on the new project. The modernisation work focussed specifically on small­scale power stations Brennet, Maulburg I, Fahrnau, Hausen I and Atzenbach, as well as the Schopfheim facility, which naturenergie operate on behalf of a third­party provider. “Our job is basically to completely replace the electrical and control equipment at these facilities, both the main hardware as well as the sensors and actuators. We’ll also upgrade the visualisation software,” as project leader Pirmin Schneider explains. The project package included the control panels, high­voltage components, the 400­volt distributor, and the generator switchboard. Most of the existing control cabling could be reused. The way the experts handed them showed their true professionalism, as Tobia Walpoth recalls. “We had an electrician with more than 20 years of professional experience in our team. He was a great example for our younger team members, showing them how a job well done pays off in the end. Once he’d disconnected

Tobia Walpoth explaining the benefits of modern visualisation technology.

a cable, he’d always label it properly before connecting it to the new terminal block. When we took the systems back into operation, there was not a single sensor that wouldn’t work straight away.”

Unification for state-of-the art operations

The control units used in each of the facilities was a Siemens Series 1500 PLC, an advanced control system that enables complex control tasks while ensuring high­level fail­safety. This way, it was possible to meet two of the customer’s requirements at once: the demand to use only latest­generation technology, and to ensure technical uniformity as well as long­term availability of replacement parts.

As Walpoth recalls, a typical example of the challenges that Troyer’s engineers were faced with was the Maulburg I facility. As the last one to be completed in 2024 it exhibited a lot of the basic problems affecting the group of facilities as a whole: “The forebay, the trash rack cleaning system and the machine unit were all fitted with control systems from different manufacturers. That’s three different control arrays for three key components. No wonder the communication between them didn’t really work as it should,” says Walpoth, adding that “We implemented a uniform system that brings all components together at a single point of control. For one thing, the different components can now be accessed remotely. And the turbine operation and forebays can also be adjusted as needed across the entire group of facilities. That’s state­of­the­art water power utilisation as it should be.”

Access via unified visualisation

This also applies to the visualisation solution. Acting as an interface between the process controls and human staff, visualisation is an all­important tool that today’s hydropower facilities couldn’t do without. For many years Troyer have been providing a special software for this purpose. It generates a welldesigned graphic representation of all processes, simplifying the tasks of controlling and monitoring relevant operational parameters. “We’ve installed the new­generation visualisation software we launched some three years ago. It runs on a PC in a control cabinet, which communicates with the PLC via a data exchange connection. This means the visualisation tool is operated autonomously at each power station within the group.

The control system is based on a Siemens S1500 SPS unit. The visualisation software was upgraded to a web-based system developed by Troyer.

© Troyer

© Troyer

But what makes this system special is that it gives all visualisation­enabled touch panels and computers access to the central server via a web browser.

„The fact that interferences have become less frequent thanks to the new control systems saves costs. And should a malfunction occur, it can be resolved remotely if necessary,“ says Tim Schöne, team leader for small power plants at naturenergie hochrhein AG.

This way, the entire system is always fully synchronised and up­to­date. For example, to add a new operating parameter you only have to set it up once to make it instantly available to all visualisation instances throughout the system. Admittedly that’s also a big plus for us as providers, as our software engineers have to implement changes only once. Previously they had to modify each touch panel individually to implement a change. Fortunately, that’s now a thing of the past,” says project leader Pirmin Schneider.

With the introduction of the new visualisation solution a new era has dawned for the power stations. “The visualisations show all the relevant readings and performance details, both the current ones and archived earlier ones. We now get all the sensor data in real time. Previously we had to count ourselves lucky to get even a few current readings now and then,” as Tim Schöne explains.

Full control via an overarching control system

A new, overarching control system turned out to provide a significant performance boost in terms of unification and optimisation. “An overarching control system wasn’t even part of our

original plan. But once Troyer presented it to us, we knew that this was the way to go,” as Tim Schöne recalls. Technologically speaking, the solution provided by Pirmin Schneider’s team is a cloud­driven solution with a web­based open­source GUI. Operational data of the individual power stations are uploaded to the Cloud, from where they can be accessed for on­screen visualisation. The design of the overall control and automation system is based on an overview display. It provides a summary of all relevant operational data across all facilities within seconds. “On the visualisation panel we can instantly see if there is a problem at one of the facilities. The control desk provides remote access to the individual visualisation instances. This, in turn, gives the operator access to the operational processes at the individual power stations. In addition to the six modernised facilities we also integrated the Hottingen and Mambach power stations – the ones that were equipped with Troyer systems around 10 years ago. Further facilities are expected to follow, as Schöne confirms. “We’re also planning to integrate all the existing facilities that are currently using third­party equipment into our new control solution.” As Tobia Walpoth points out, first steps to do so have already been taken. “We’ve installed gateways at most of the facilities to make them fit for the new control technology. It’s all well supported technically.”

Remote control ensures economic advantage

As far as Time Schöne and his team of engineers are concerned, having a wide range of new remote monitoring and control options available is one of the brightest highlights of the successful modernisation project. Aside from providing better, more fine­grained control options, the solution has also saved the team a lot of on­site work. “Now our operating staff can access the facilities conveniently from home. The power stations are completely remote controllable. Previously, you had to be on­site to adjust a control parameter. Lots of tasks that used to require manual intervention are now fully automated,” says Tim Schöne, adding that “With the new controls reducing the number of incidents, our costs have gone down quite a bit. And even in case an incident does occur, it can be resolved remotely. This saves us not just the costs for frequent on­call and weekend duty, but also the need to drive back and forth – after

The historic power house of the Hottingen hydropower plant. (Built in 1908)

The machines of the Hottingen hydropower plant were successfully integrated into the new control system.

Switch cabinets for the control system – also supplied by Troyer.

© Troyer

© Troyer

© Troyer

As for visualisation, Troyer has developed its own software. In addition to providing a clear on-screen representation of operational processes and relevant parameters, it is particularly easy to operate.

all, some of the facilities are up to a 60 kilometre drive away from the control room. What’s more, these time savings mean longer operating hours for our facilities, which helps to boost economic efficiency.”

Perfect coordination between components

In addition to lowering the number of incidents, the new control equipment has also allowed the operators to optimise the energy efficiency of the facilities. As Tobia Walpoth explains, “Today it’s state­of­the­art for the various parts of a power station, like the forebay and power house, to communicate with one another via data exchange. This way, they can be fine­tuned to ensure an optimum energy output. To make that possible we’ve installed fibre­optic connections between the more remote components, and Ethernet connections for shorter distances. With the new controls in place, we are able to implement optimisations to ensure longer operating times and resulting higher annual energy output.”

Another benefit, says Troyer’s expert technician and software engineer, is the modern sensor array that has been installed as part of the project. It provides more and higher­quality data, which can also be used for maintenance purposes. Translated into graphs and diagrams, the accurate readings enable precise, economically efficient maintenance planning.

Automation team demonstrates competence and flexibility

Using a special interface, Troyer’s stand­by automation team also has remote access to the control and automation system of naturenergie’s modified power stations to take action as needed. Especially when it comes to making minor adjustments or addressing unexpected error messages, the South Tyrolean team of experts are standing ready to react and respond promptly and accurately. “This arrangement has been working perfectly. A telephone call is usually all it takes to have the adjustment applied by the next day,” says Tim Schöne, paying Troyer’s team a compliment by adding, “We were highly impressed, not just with their quality of work but also with their speed and flexibility in getting things done. Especially when we needed some adjustment at short notice or when we needed some extra feature, they always responded in a friendly and professional manner. Our collaboration was highly successful – we really enjoyed working with them!”

A prolongation of the collaboration is already highly likely. That is because the control equipment in the two power stations operated by naturenergie on behalf of third­party providers are also scheduled for an upgrade in the not too distant future. And the other facilities that were excluded from this project are likely to require a similar control and automation upgrade in the coming years.

About naturenergie

naturenergie Group’s beginnings date back more than 125 years, Since then, their focus has always been on environmentally friendly energy from hydropower. To this day, the group is fully committed to regionality in all its operations, which are centred around the southern part of Baden, the north-western region of Switzerland, and the canton of Valais.

At present, around 200,000 households benefit from ecopower provided by the naturenergie Group. The energy is generated by the group’s own hydropower stations on the Upper Rhine, in the southern Black Forest region, and in Valais. Organised as a German-Swiss public company, the naturenergie Group is listed on the Swiss stock exchange. The group is also a holding company of EnBW, one of Europe’s leading energy providers.

The tradition-steeped Mambach power station in Germany’s Black Forest region has been in operation since the late 1890s. This makes it the oldest hydropower facility in the entire surrounding Wiesental region.

The control system used at the Mambach power station is still up to current standards and was integrated seamlessly into the new control and automation platform.

© Troyer

© Troyer

© Troyer

FLAGSHIP PROJECT : GREEN ENERGY ON THE KENTUCKY RIVER

Berea College and Appalachian Hydro Associates (AHA) are relying on Voith’s expertise for their pioneering renewable energy project – the Lock 14 hydropower facility on the Kentucky River in Heidelberg, Kentucky. With Voith supplying six innovative StreamDiver turbines, Lock 14 will generate several gigawatt-hours of clean electricity annually, making a significant contribution to Berea College’s sustainability strategy. Combined with the existing Lock 12 hydropower facility, the college will be able to cover its entire electricity demand through renewable energy. Additional projects along the Kentucky River, based on this innovative concept, are already in the pipeline.

The Kentucky River features 14 historic locks and dams originally constructed between 1836 and 1917. Once used for transporting raw materials like coal and iron via shipping, most of the locks ceased operations about 30 years ago. Today, these structures provide an ideal foundation for modern, environmentally friendly energy generation.

The Lock 14 project builds upon prior experience in utilizing existing hydraulic structures for renewable energy. A prime example is Lock 12, where the same project developer commissioned Kentucky’s first new small hydropower plant in 94 years in May 2021. This spearhead project demonstrated that decommissioned locks offer a valuable basis for sustainable energy production.

With more efficient technology and an optimized construction approach, Lock 14 is setting new standards. The fully submerged machinery is designed to withstand even the extreme flooding of the Kentucky River, which frequently experiences water levels over 10 meters above the normal gage. Furthermore, construction takes place within the decommissioned lock chamber, eliminating the need for costly and complex cofferdams and excavation pits, which are typically required for hydropower plants.

From planning to implementation: a sustainable concept Voith was contracted to supply turbine technology for the project. With its extensive experience in small hydropower plant development, Voith has provided a tailored solution for the site with its innovative StreamDiver technology. The plant’s design is based on a concept that remains confined within the existing lock chamber and is fully submerged. Large debris is diverted from the plant by a flood-resistant floating log-boom positioned upstream of the intake structure and guiding debris to the fixed crest dam. Within the lock chamber, the upstream water level is regulated by an inflatable rubber weir, which can be lowered to flush the horizontal, submerged trash rack. The turbine units themselves are positioned below the trash rack.

Initial planning for Lock 14 began in 2019, with construction starting in 2022 and commissioning scheduled for spring 2025. Voith is responsible for supplying the turbines, turbine valves, and power cables, as well as overseeing installation and commissioning of those.

In addition to flood resilience, the standardization of the concept is a major advantage: since the lock chambers along the Kentucky River have uniform widths, the design can be efficiently replicated for other locks. This facilitates planning and licensing for future hydropower projects.

Technological innovations for maximum efficiency

Lock 14 features an innovative design that enhances power generation efficiency while reducing construction efforts. Compared to the first project, Voith experts guided the developer towards a new design concept that allows 30% more energy to be generated within the same lock chamber dimensions.

Technological highlights:

• Horizontal Installation: Unlike Lock 12, which used vertical turbines, Lock 14 features a horizontal configuration. This design reduces concrete requirements by approximately 40%, significantly lowering construction costs and time while ensuring efficient and sustainable power generation.

Oil-Free Technology: The maintenance-friendly, water-lubricated, and oil-and grease-free StreamDiver turbines minimize environmental impact and enable nearly silent electricity generation, as they are fully submerged.

Challenges in implementation

As Lock 14 is being built within an existing lock chamber, integrating cutting-edge hydropower technology into infrastructure that is more than 100 years old presents a unique challenge. Rock anchors were used to stabilize the structure during construction when the lock was fully dewatered. The design had to be adapted to ensure that the new StreamDiver turbines fit

Voith Hydro facility in Austria – preassembled units, installed in less than a day.

© Voith Hydro

© Voith Hydro

optimally within the existing structure without compromising stability. At the same time, the plant had to be engineered to withstand extreme flood events on the Kentucky River while remaining easily adaptable for future projects. These floods happen frequently, also during the construction period. The developer has already secured licenses for four additional identical projects on the same river.

Technical Details of Lock 14

Innovative turbine-generator combination: The plant will be equipped with a total of six Voith StreamDiver turbines, including four StreamDiver units with a runner diameter of 1,490 mm, directly coupled with a 642 kW permanent magnet generator, and two StreamDiver units with a runner diameter of 895 mm, directly coupled with a 222 kW permanent magnet generator. The six horizontal StreamDiver turbines will achieve a total capacity of 3 MW.

The combination of different turbine sizes allows for optimal adaptation to the river’s flow curve in 14 regulation steps despite unregulated turbines.

TECHNICAL DATA

• Turbine Type StreamDiver

• Installation Type Horizontal

• Head 4,83 m

• Number of Turbines 6

• Total Capacity 3 MW

• Water Flow 4x 16,5 m³/s + 2x 5,7 m³/s

Significance for the future of Hydropower

Lock 14 is more than just a hydropower project – it demonstrates how unused historic locks and dams can be transformed into modern, sustainable energy sources.

“Choosing Voith’s StreamDiver technology was a crucial step for us in efficiently integrating renewable energy into existing infrastructure. Thanks to Voith’s early involvement, the project was optimally aligned and implemented efficiently. The easy installation and minimal environmental impact convinced us. Additionally, Voith not only provided innovative solutions but also ensured that the concept could be easily replicated, supporting long-term sustainable energy generation.” – [David Brown Kinloch, President Appalachian Hydro Associates]

The uniform width of the lock chambers along the Kentucky River ensures a high level of design repeatability. As a result, this concept can be efficiently replicated for other locks and directly incorporated into the execution of already planned hydropower projects along the Kentucky River.

Hydropower as a sustainable solution

One of the project’s primary objectives was to minimize environmental impact. In addition to the innovative, oil- and grease-free turbine technology, further measures were implemented, including specialized fish protection systems with fine, horizontal trash racks and optimized water flow management to preserve the ecological balance of the Kentucky River. At the same time, Lock 14 underscores a strong commitment to social responsibility: revenues from electricity generation will directly support educational programs for underprivileged students at Berea College, promoting equal opportunities. With its planned commissioning in May 2025, Lock 14 will make a significant contribution to a sustainable energy future. The concept has the potential to serve as a model for many future projects across North America, further advancing the use of historic hydraulic structures for climate-friendly energy generation.

Lock 14 on the Kentucky River before the start of the hydropower project.

© Voith Hydro

In partnership with AES Mega, GUGLER Water Turbines GmbH successfully completed its first reference project in Taiwan in February 2025, delivering the complete electromechanical and I&C equipment for the Hushan power plant.

AUSTRIAN HYDROPOWER EXPERTS SUPPLY HIGH-PERFORMANCE TECHNOLOGY FOR TAIWAN‘S HUSHAN HYDROPOWER PLANT

In February 2025, the internationally renowned GUGLER Water Turbines GmbH successfully completed its first project in Taiwan. The Austrian industry specialists supplied the complete electromechanical and control system equipment for the new construction of the Hushan small hydropower plant of the operating company AES Mega, a pioneer of closed-loop small hydropower plants in Taiwan who conducted the feasibility study, basic design, PCM, and EPC of the project. The centrepiece of the power plant is a highly efficient Francis turbine, which achieves a maximum output of 1657 kW at full water supply. The exemplary plant was built next to the water treatment plant of the Taiwan Water Company Yunlin, which is supplied from the nearby Hushan reservoir. In addition to the powerful technology, the power plant also boasts an extremely attractive appearance with its wooden structures. The success of the project reflects the excellent teamwork between the European company GUGLER and the Taiwanese company AES Mega, combining technological expertise and local know-how to deliver a showcase hydropower installation.

The island state of Taiwan, which has around 23 million inhabitants and is located around 130 kilometres east of the Chinese coast, has ideal conditions for generating electricity from hydropower due to its abundance of water and mountainous landscape. Despite these favourable conditions, hydroelectric power production in Taiwan only plays a very minor role. According to the online portal „lowcarbonpower.org“, around 83 per cent of the electricity generated in Taiwan in 2024 came from fossil fuels such as coal and natural gas. Only 3 per cent of electricity was generated by hydropower plants, while photovoltaics and wind energy were also far behind with a share of 4 per cent each. Despite these sobering figures, there are strong endeavours in the country to promote the use of renewable forms of energy.

First reference project in Taiwan

AES Mega, which was founded in 2018, is one of the biggest proponents of Taiwan‘s energy transition. The company, which

is based in the capital Taipei, specialises in the use of sustainable energy, including the construction of hydropower plants

The Hushan reservoir holds over 52 million cubic metres of water.

TAIWAN

© GUGLER

and geothermal energy systems. Only recently, AES Mega‘s latest own hydropower plant, which was built in the western part of Taiwan near the city of Douliu, produced clean electricity for the first time. The Upper Austrian hydropower all-rounder GUGLER Water Turbines GmbH played an important role in the technical realisation of the Hushan power plant, qualifying for the international tender to supply the machine set, says GUGLER project manager Markus Weglehner: „The project was a premiere for us: We were able to demonstrate our expertise in Taiwan for the first time. In principle, the order comprised the realisation of the complete electromechanical equipment. This included a Francis turbine including generator, two hydraulic units, four butterfly valves and the power plant control system.“

Power generation and drinking water supply combined

The new hydropower plant from AES Mega utilises the hydroelectric potential of the Hushan reservoir, which was built to supply drinking water to the district of Yunlin. The reservoir, which has a capacity of over 52 million cubic metres, was created by the construction of the 75-metre-high Hushan dam and was officially inaugurated in 2016. Around five kilometres from the dam is the state-operated drinking water treatment plant of the Taiwan Water Corporation Yunlin, next to which the new small hydropower plant was built. „The general operating principle of the Hushan power plant is not complicated. After the water is discharged from the Hushan reservoir, it is utilised for the first time by a slightly older power plant to generate electricity. After turbining, the water flows to a relatively large stilling basin, which is connected to a penstock. This DN1800 power descent finally leads to the treatment plant or the newly built hydropower plant,“ explains the project manager.

Bypass is required

According to Markus Weglehner, connecting the turbine to the existing penstock involved some additional work: „Normally, a turbine draft tube has the technical freedom to be turned a few centimetres to the left or right, as it flows into an unpressurised channel anyway. However, this was not the case at the Hushan power plant because the pipework leading to and from the turbine was already in place. These circumstances made additional clarification necessary during the construction phase so that the machine could be fitted

exactly between the two pipe axes.“ The integration of the new hydropower plant into the existing penstocks also required the installation of a bypass system. The bypass, for which GUGLER supplied three additional butterfly valves, ensures that the treatment plant can be constantly supplied with water even in the event of a power plant shutdown or mandatory maintenance work.

Francis turbine with high efficiency

With an expansion water volume of 3 m³/s and a net head of 60.7 m, the use of a horizontal-axis Francis turbine was the ideal option for the Hushan power plant, according to Markus Weglehner. The machine, which achieves a nominal output of 1657 kW at full water supply, guarantees the operators the best efficiency and consistently effective electricity production. The machine set is completed by an air-cooled synchronous generator from the Italian manufacturer Marelli, which is directly coupled to the turbine runner. Equipped with roller bearings, the generator was designed for an operating voltage of 690 V and a rated apparent power of 1870 kVA. For the manufacture of the turbine, GUGLER relied on proven European partner companies with decades of experience in the mechanical engineering sector. Following factory acceptance in the presence of a customer representative, the machine, which was delivered largely pre-assembled, was packed seaworthy and sent on its journey to Taiwan by ship. „Due to the unstable security

TECHNICAL DATA

Flow rate: 3 m³/s

Net head: 60.74 m

Ø Penstock: DN1800 m

• Material: steel

Turbine: Francis-Spiral-Turbine

• Turbine axis: horizontal

Maximum ouput: 1657 kW

• Manufacturer: GUGLER Water Turbines GmbH

Generator: synchronous

• Voltage: 690 V

Nominal Output: 1870 kVA

• Manufacturer: Marelli Motori

At full water supply, the turbine achieves 1657 kW maximum output.

The machine set guarantees maximum efficiency.

situation off the coast of Yemen, caused by activities of the Houthi rebels, an alternative shipping route around the African continent was selected for safety reasons. Despite the extended sea voyage from Europe to Asia, which took nearly three months, the overall project schedule was successfully maintained,“ Markus Weglehner noted.The installation of the machine set and the various technical trades in the powerhouse took place from mid-2024 and was carried out in several stages by local personnel under the guidance of a GUGLER supervisor. In addition to the electromechanical equipment, GUGLER‘s scope of delivery also included the power plant control system, which ensures the fully automatic operation of the plant. GUGLER subsidiary H&W Control GmbH, also from Austria, was responsible for programming the control technology with intuitive visualisation. The system can be controlled and monitored either in the machine building on the control technology PC or in the AES Mega control centre in Taipei via a secure online connection. The electrical components such as the medium-voltage switchgear, protective devices and transformers were installed by the operating company itself.

Impressive system inside and out

„After the final installation work, it was finally time for the commissioning process in February 2025. Extensive mechanical and electrical tests and checks were carried out as part of our standardised commissioning protocol. The findings with regard to the functionality and confirmed performance potential of the

system were extremely satisfying for both us and the representatives of AES Mega. I believe that we made a very good impression during our first deployment in Taiwan,“ emphasises Markus Weglehner. Speaking of good impressions: the project manager points out that during the realisation of the Hushan power plant, great importance was placed not only on the high-performance technology, but also on the attractive appearance of the plant. Japanese architect Hojo Kenji was responsible for the attractive appearance of the machine building with its large glass façades, which give visitors to the power plant an unobstructed view of the modern hydroelectric technology inside.

The remarkable machine building was designed by Japanese architect Hojo Kenji.

HYDRO 2024 THE ENTIRE WORLD OF HYDROPOWER UNITED FOR THREE DAYS IN GRAZ

The highlight event in the field of hydropower took place in the autumn of 2024 in Graz, the second-largest city in Austria. From November 18 to 20, the international hydropower community gathered at the Messe Congress Graz (MCG) to learn about the latest trends and developments and to forge new connections as part of HYDRO 2024. Under the main slogan „Secure Hydropower in Turbulent Times,“ the event focused on the most pressing and critical issues surrounding the use of hydropower today. Approximately 1,200 participants from 72 countries attended and contributed to the success of the Aqua-Media conference.

Following the success of HYDRO 2023 in Edinburgh, Scotland, expectations for this year‘s event were high, and all eyes were on HYDRO 2024 in Graz. For three days, the focus in the halls of Messe Congress Graz (MCG) was entirely on all aspects of hydropower. After a warm welcome from the organizer and director of Aqua-Media, Ms. Alison Bartle, and introductory words from representatives of AMI, ICOLD, IEA, Verbund, and ATCOLD, the presentation of the EU-funded ETIP initiative was given by three well-known hydropower experts: D. Aelbrecht, Prof. A. Schleiss, and A. Harby. Day 1 of the prestigious event was dedicated to a range of hydropower topics, spanning a wide variety of subjects. These included floating photovoltaic (FPP) systems and various hybrid projects, where

Prof Dr. Anton Schleiss of Switzerland, giving a talk on the EU ETIP initiative, during the opening session of HYDRO 2024.

Around 1,200 participants from 72 nations came to the Messe Congress Graz (MCG) in Austria to take part in the HYDRO 2024.

basic design aspects and specific application examples from Brazil and the Philippines were presented. In the hybrid concepts, presentations showed how photovoltaic and hydropower can work optimally together. Another key topic addressed the various types of monitoring erosive cavitation. Specific focus was placed on the adaptation of turbine types to conditions with a high risk of erosion. Additionally, innovative approaches to „Turbulent Vortex Turbines“ were introduced, offering new perspectives for low-head applications. Other topics co vered included different approaches to the design, operation, safety, and maintenance of dams worldwide, both in theory and practice, as well as project financing opportunities and legal aspects related to insurance and risk management. The field of pumped storage, with numerous application examples and case studies from current power plant projects, was also discussed on the first day of the event.

Digital solutions for hydropower

Day 2 in Graz began with a focus on the development of hydropower in Africa, highlighting some interesting recent project examples. Projects specifically developed in geographic border areas were also discussed, emphasizing what needs to be considered in these contexts. Two sessions were dedicated

to the increasingly important topic of artificial intelligence and example focused on the concept of Digital Twins in the service ample of hydropower. Another session was entirely dedicated to digital solutions for the operation and maintenance of exists its role in the further development of hydropower. A primary example focused on the concept of Digital Twins in the service of hydropower. Another session was entirely dedicated to digital solutions for the operation and maintenance of existing plants.

In addition to dam safety and risk management, pumped storage power plants in their various forms were also discussed. Even seawater applications were addressed. Another session was devoted to the crucial topic of steel water construction: closure and shut-off devices, and technical solutions for water intakes. Other topics on Day 2 included climate and hydrological conditions, as well as tunnel and shaft construction.

Reunion in Greece 2025

On the final day, activities of the major hydropower organisation IEA Hydro were presented. Ecological issues, especially fish protection, were the focus of several presentations. One session was dedicated entirely to the important topic of „Pressure Pipelines“ and their monitoring and maintenance. A significant amount of time was also dedicated to the increasingly important topic of sediment management, along with modern technical methods for optimal sediment handling, supported by practical examples. Furthermore, topics related to electrical engineering, environmental issues, and societal relevance rounded off the final day of the event.

The Aqua-Media event team was once again able to draw a successful conclusion in the Austrian „Mur Metropolis.“ Both the approximately 1,200 participants from 72 countries and numerous representatives of the hydropower industry were highly satisfied with the event. The next edition, which will take place in Thessaloniki, Greece, from November 24 to 26, 2025, is already marked on the calendars of Europe‘s hydropower enthusiasts. The event location is well chosen, as Greece is entering a new era of hydropower development, with both run-of-river and pumped storage power plants planned in greater numbers.

HYDRO 2024 was a complete success for the organizers of Aqua-Media. In the image Ms. Alison Bartle, organisation director and president of Aqua-Media. The HYDRO 2025 will take place in Thessaloniki, Greece.

Josef Mayrhuber, Member of the Board at Verbund, Austria, responsible for Asset Management, giving his opening address.

represented.

INDUSTRY PROFESSIONALS MULTIPLY POWER PLANT OUTPUT

WITH REPLACEMENT CONSTRUCTION IN SOUTH TYROL

In hydropower, tradition and modernity often go hand in hand. Operators in St. Johann in Ahrntal, South Tyrol, have reawakened a traditional site in the centre of the village with the installation of cutting edge hydropower technology to create their own state­of­the­art green energy plant. The plans compiled by the Bruneck planning office Studio G show how the old Schmied hydropower plant, that had previously only achieved a power output of 15 kW, was completely renovated to generate 340 kW and supply around 1.3 GWh of clean electricity per year. The site also underwent enormous improvements in terms of water ecology, and the new power plant has been in regular operation since August 2024.

Few valleys in South Tyrol can boast such an abundance of water as Ahrntal. No fewer than 38 smaller glacial formations in the surrounding three-thousand metre peaks ensure that Ahrntal and its side valleys have plenty of water flowing through them. Previously, this was channelled toward the fields for agriculture via above-ground free-flowing channels, a well-known system called the ‘Waale’.

Obviously. These resources were also used to power various trades, including mills, forges and sawmills. Since the last century, it has been used by numerous power stations to generate electricity. Modern small-scale hydroelectric power stations, particularly those built here in the last 20 years, show how water power potential in the Ahrntal Valley can be harnessed effectively using the very latest small power station technology.

A history of blacksmithery

The old Schmied power station in the centre of St. Johann im Ahrntal was, until a few years ago, anything but modern. The original plant failed to meet the standards and requirements of modern hydropower applications, either in terms of technology or fish ecology. At a site with a long history, the old turbine merely delivered 15 kW of power – so action was required. “Utilisation of water power from the Ahr at the ‚Schmied‘ in St. Johann dates back to the 18th century. For many decades forge machinery was driven by belts and mechanical drives. In the 20th century the power of the Ahr was harnessed for electricity production via a turbine and generator. The blacksmith’s trade was practised by the ancestors of the current owners until the mid 20thcentury. Historically, it formed the economic basis that supported several generations,” explains Adolf Dengg (Dipl.-Ing.). As the Studio G engineering planner from Bruneck

The old power plant at this traditional site in St. Johann in Ahrntal Valley was replaced by a modern run-of-river power plant, greatly increasing the power plant‘s output. In the picture: the new intake structure on the Ahr.

The excavation pit was sealed off from the stream bed with an earth dam so the concreting of the intake, inlet channel and underground powerhouse, could be carried out in dry conditions.

A bird‘s eye situational overview of the Schmied power station. The transverse and longitudinal sills in the stream bed can be seen clearly. The transverse sill was especially adapted for residual water dotation and the entrance to the fish pass.

responsible for the new power station, Dengg is obviously familiar with every single detail of the plant.

More water – greater yield

A few years ago the current Schmied owners joined forces with several interested parties to form a company with the aim of continuing the tradition of hydropower at the site in an optimised form. To this end the newly founded Kraftwerk Schmied GmbH commissioned Studio G, a highly-reputed planning office in the region that has been very successful in the realisation of numerous hydropower projects in South Tyrol over recent decades. Key expectations placed on the replacement infrastructure were an increase in the volume of water processed, modernisation in terms of water ecology, and the use of stateof-the-art electromechanical components. Dengg added: “The flood protection structures were renewed and reinforced throughout the entire plant area.”

Construction process challenges

Construction work began at the beginning of September 2023.

The extreme tightness of the space between the residential building and the riverbed meant the construction pit – which extended to around 4 metres below the stream bed – had to be sealed all the way around by way of jet grouting. This method, also known as soil compaction grouting, is a form of earth grouting used to create cement-soil composites in the ground. In-situ soil is mixed with a cement-containing binder suspension under high pressure.

Power plant planner Adolf Dengg explains: “Transverse and longitudinal sill implementation was realised in the stream bed during the period of low water-levels. The transverse sill was dimensioned to accommodate residual water allocation and the fish pass entrance.” In addition, the stream bed was separated from the site excavation via earth damming so that the concreting tasks for the intake, intake channel, underground powerhouse, transfer cabin and return channel, could all be carried out in a dry environment.

Safety with high­quality steel construction

A shut-off gate was installed upstream of the flushing channel at the catchment. At 9 metres wide, 2.5 metres high and made of concrete, safe closure was ensured under its own weight –even without electricity. The entire hydraulic steel construction

of the water intake was implemented by the specialists at South Tyrol company Wild Metal, one of the best-known names in the industry. Wild Metal’s scope of services also included the inlet gate, which closes off the flushing channel positioned behind it. The upper part of the steel structure can be lowered once the trash rack cleaner has pushed the flotsam off the horizontal screen and downstream. Cleaning system is a hydraulically operated, fully automatic horizontal trash rack cleaner, and offers immense advantages – particularly fish-friendly power plant operation. Tight bar spacing and lower flow velocities on the horizontal rake reduce the hazards for fish in the Ahr significantly. An additional plus point for Wild Metal trash rack cleaners is that – right from the basic design stage – the South Tyrolean industry engineering specialists attach great importance to the easiest possible accessibility to spare and wear parts, and to components requiring maintenance. Thanks to their extremely robust design, Wild Metal‘s trash rack cleaners guarantee a long working life and ensure a high degree of operational reliability, even under the most adverse operating conditions.

Power generation in immersion mode

The water is channelled through an inlet 4.5 m wide at the side intake of the new water catchment. It drops away over the last few metres down to the machine set consisting of a double-

A concrete sluice gate was installed directly in front of the flushing channel. This ensures safe closure under its own weight, even without electric power.

© Brunner & Leiter

regulated Kaplan tube turbine and a directly-coupled submersible generator. “The machine set was also installed with an inclined axis in order to direct the water flow onto the blades of the Kaplan turbine as effectively and with as few deflections as possible. The submersible generator protrudes into the headwater and is thus water-cooled,” explains Adolf Dengg. Here, the benefits of a Kaplan tube turbine are that the inlet shaft, turbine and draft tube are arranged without any change in direction, meaning this type of turbine is very efficient – and that the design is extremely compact. Designed, manufactured and delivered by Sora – the South Tyrolean turbine

specialists – for a volume capacity of 13 m3/s, the modern turbine, accommodates a net head of 3.20 m at Qmax. At maximum the Kaplan turbine generates an output of 340 kW – truly a quantum leap from the 15 kW achieved by the old turbine.

This reference project has had a significant external impact for the turbine manufacturers at Sora, having enabled the company to prove its capacity to deliver high-performance turbines for the low-pressure sector. Similarly, Sora has enjoyed success in the medium-pressure range, having recently added the diagonal turbine to its product portfolio and having seen it put into operational use.

TECHNICAL DATA

Flow Rate: 13.0 m3/s

Net-Head: 3.20 m

Turbine: Kaplan

Runner Speed: 250 rpm

Output: 350 kW

Manufacturer: SORA

• Generator: synchronous

Control Technology: en-co

• Hydraulic Steel Construction: Wild Metal

Bottom Outlet: w 1500 x h 3600 mm

• Inlet Gate: w 9000 x h 2500 mm

Outlet Gate: w 3500 x h 2300 mm

Trash Rack Cleaner: horizontal

Rack Size: w 9000 x h 2000 mm

Annual Production: 1,3 GWh

A solid inlet gate was supplied by Wild Metal, the well-known South Tyrolean industry specialists. The sluice gate is 9 m wide and 2.5 m high.

Proven horizontal screen cleaning technology manufactured by Wild Metal.

The Kaplan turbine can process up to 13 m3/s of water for a power output of up to 340 kW.

Noise emission­free hydropower plant

The waste heat from the generator is transferred to the engine water via the stator housing. An internal air circuit in the generator ensures the rotor is cooled accordingly. The generator is hermetically sealed and surrounded by drive water, so noise levels are minimal.

Following the further course of the discharged headrace water, the large outlet gate with dam beam inspection slots is located after the concreted-in steel suction pipe connected directly to the turbine. The return channel then rises diagonally to the 17-metre outlet sill. The control room is located above the turbine, and to facilitate easy access the transfer cabin had to be positioned to the side – as specified by the local grid operator. The small rooms opposite are for the transformer and medium voltage power management. As the system was built directly onto the neighbouring residential building in this area, this section and the first few metres of the return duct were fitted with external sound insulation. This achieved the desired effect. Vibrations can no longer be felt in the existing building during operation, nor can any transmission of structurally transmitted noise be detected.

Average annual power output of 1.3 GWh

In just less than a year the operators of the new Ahrn power plant in St. Johann succeeded in replacing a small, outdated and inefficient power plant with a modern, high-performance set-up. The new infrastructure is state-of-the-art in every respect. After a short trial phase in July last year, the new Schmied power plant went into regular operation at the end of August 2024. The new hydropower plant is green, in keeping with the generation-spanning tradition of hydropower utilisation at the location, and is one of numerous modern small hydropower plants along the water-rich Ahrntal valley. Now, the new lowpressure plant can supply an annual average of around 1.3 GWh of clean electricity, contributing significantly to the local energy supply. This project also represents an important building block in the South Tyrolean energy strategy, according to which around 100 % of South Tyrol‘s electricity requirements are to be covered by renewable energy sources by 2050.

• Energy distribution

• Water supply

• Hydropower plants

• Off grid systems

• Medium voltage systems

• Low voltage systems

• Automation

T

• Control systems

• Planning / Design of Hydropower units

• In-house manufacturing of:

High-pressure turbines

Low-pressure turbines

Off grid systems

• Revitalization of turbines

• Protection technology T

• Service & Installation work

HITZINGER: BACK TO ITS BEST

After around a year within the Techco Group, HITZINGER, the Linz-based company with a long tradition of generator manufacturing, is well on the way to regaining the status and repute earned within the hydropower market over many years. At HITZINGER, the whole world revolves around electric machinery. Now the economic turbulence of 2023 has been left behind the company is ready to concentrate all efforts on its core area of expertise: the production of customised power generators for navy, rail, industrial, and – above all – hydropower applications. HITZINGER‘s reorganisation has led to the development of refurbishment and repairs as a separate area of business expertise, enabling the experienced machine-building specialists to contribute their extensive hydropower sector knowledge and know-how to the refurbishment of existing generators.

HITZINGER has stood for supreme-quality sustainable energy generators for almost 80 years. Headquartered in Linz, Austria, many decades of experience, and products that have always met the toughest market demands, have contributed to the excellent reputation the company enjoys within the industry. The company‘s trademark has always been the provision of customised energy solutions for specific requirements, and the capacity to incorporate numerous special and specific customer requests – establishing standards in the past that the company intends to uphold long into the future. “It’s logical that a reputation like ours generates a corresponding level of expectation. Past successes demand that we continue to guarantee the highest quality solutions – so nothing has changed in this respect,” states Dr. Daniel Huber (Dipl.-Ing.), Managing Director for Technology and Sales. The continued existence of the longstanding Linz-based HITZINGER brand is due in no small measure to the unwavering support and loyalty of its customers, and is now clearly being reflected in the order books. Huber continues: “The numerous orders from within the hydropow-

er sector are a great motivator. They show us that customers have maintained their belief in – and appreciation of – the quality and performance of our generators.”

Utilising new synergies

HITZINGER Power Solutions GmbH emerged from the 2023 insolvency, and has been part of the Austrian Techco Group since February 2024. The Linz-based generator manufacturer has a long history, and has been integrated into the secure environment of a stable industrial group that currently employs around 400 people, generating an annual turnover of 60 million euros. Daniel Huber believes potential synergies can be utilised moving forward: “Above all, the opportunities we see for leveraging synergies in the hydropower sector stem from the fact that the group includes a manufacturer of mechanical sheet-metal bending parts and a manufacturer of switchgear and transformer stations. These are overlaps that HITZINGER can, and definitely will, utilise in future collaborations within the hydropower sector.”

HITZINGER hydropower generators are in use all over the world. After integration into the Techco Group in February 2024, the long-established company from Linz is now back at full power.

HITZINGER’s corporate culture proves its worth

One significant reason the HITZINGER brand survived the troubles of the previous year unscathed was the unbroken loyalty of its employees. The takeover by the Techco Group facilitated the retention of central know-how carriers in key positions. Managing Director Daniel Huber explains how sustained employee cohesion and a willingness to face the challenges together were of great benefit: “Over the years, the firm’s corporate culture ensured employees had built up a strong bond with the HITZINGER brand and company. A sense of togetherness had clearly developed. If it hadn’t, the company would probably no longer exist in this form. We are all very proud to have got through this together.” Huber returned to the Linz-based generator manufacturer after a brief stint with another company. In the last few months the company has also managed to bring back some proven employees who have expressed their belief in the new Techco Group setup. Philipp Oberndorfer, head of the sales team in the hydropower sector, is, like Daniel Huber himself, a well-known figure within the hydropower industry.

HITZINGER is justifiably proud of having employees it can refer to as ‘longservers’. The longest-serving and bestknown employee of all is Helmut Roland, a mechanical engineer who joined the

company in 1979, and now makes his wealth of experience and knowledge available to the company as an expert consultant.

In-house engineering expertise

Along with HITZINGER’s commitment to research and development, the internal engineering and design expertise the business has accrued will be indispensable in the future. “We are constantly faced with the latest demands of the market, and with trends that require the right response. Grid codes, the latest requirements for the electricity grid, are perhaps the best example of this. We managed to adapt our machines in record time thanks to our extensive experience. Generators built today are expected to comply with the very latest and specific grid feed-in guidelines. Furthermore, it’s essential to consider the type of documentation the customer will require in order to obtain valid certification. We are currently leading the way in this area,” says Huber, and explains the importance of a company having a free hand in this respect: “Anyone who, like us, has mastered the design of electrical equipment down to the finest detail, will ultimately find it much easier to adapt the generators to given requirements. Dependence on third parties would make this much more difficult, which is why we need to keep this engineering expertise inhouse.” In this context, the expert points out that, as well as having to focus on the three-phase machine itself, generator manufacturers now need to be on top of the entire electrical system.

New workflow ideas

Ongoing machine development is part of everyday life at the company for Managing Director Daniel Huber: “Development is a continuous process. Drawing on decades of experience in machine design, calculation, production and testing, we are in constant pursuit of new ideas for optimisation, enabling new production techniques and materials to find their way into serial production. It’s a never-ending work in progress.” Among other things, HITZINGER has modified the product line of small scale alternators. The alternators are not only applicable

HITZINGER is proud of in-house engineering expertise that continues to ensure its independence, innovative strength and flexibility.

Despite the economic turbulence of 2023, the company succeeded in retaining key expertise.

Broad and comprehensive in-house production ensures the HITZINGER repair shop can manufacture standard parts and optimised components very quickly.

© HITZINGER

© HITZINGER

Generator regeneration

universally but also offer advantage in pricing due to the standardization of components. Of course, HITZINGER has continued its good relations with Austrian universities and universities of applied sciences, with whom the company collaborates – particularly on tricky scientific issues. This is an important channel for the transfer of expertise; a highly valued item at HITZINGER.

In addition to product development, Daniel Huber and his team are addressing various other market requirements: “The topics of digitalisation, product life cycles and life cycle costs are also playing an increasingly important role in our activities, so we are giving plenty of thought to new business models in which HITZINGER can fulfil its high expectations. It is about the question of whether a capital good should only be valued according to its purchase price or also according to its life cycle costs and ultimately aims to determine how we, as a quality supplier of electrical machines, can differentiate ourselves from our lowcost competitors from Asia. After all, we don‘t build machines where the warranty ends after two years..” In this case Daniel Huber is referring to HITZINGER generators that have provided reliable service for over 50 years, and only once required bearing replacements.

Hence, HITZINGER believes it’s logical and makes good sense to accompany the machines it has built throughout their entire life cycles. Who else is better suited to this task than the manufacturer? An independent ‘Refurbishment & Repair’ business department was set up within the company under the management of Gregor Bauer (Ing.). “As a manufacturer, we have access to all calculation documents, building regulations, original requirements and designs. That’s an entire database, some of which goes back decades. This makes it possible to compare current measurements and readings with those provided at the time of initial delivery, and to verify results reliably. Conventional repair companies do not offer these advantages. At best they can restore the status quo. If parameters have changed over the course of time, we can adapt and optimise machines to accommodate the new challenges,” says Daniel Huber on the benefits of the new refurbishment department. Work is carried out by long-serving, experienced employees. These repair work experts have gained a great deal of experience in the field over many years – ultimately for the good of HITZINGER customers.

Downtimes are critical

As a rule, refurbishing a generator is less time-consuming than building a new one. Ultimately there is less downtime for the plant. Daniel Huber elucidates: “All in all, if a clean power plant can be reconnected to the grid earlier, refurbishment is both more economical and better for the environment,” and outlines the refurbishment procedure in a little more detail: “During refurbishment, the generator is brought into the factory, dismantled, cleaned and dried by our specialist staff. Subsequently, all components are inspected, various electrical readings are taken, wear parts are replaced and the entire machine is overhauled – and that‘s just the standard programme. Customers with generators that are 20 or 30 years old usually take advantage of our advanced programme in which active parts, such as windings or protective plates, are replaced. The even more comprehensive stage 3 overhaul involves modernising existing machines and adapting them to the latest requirements – like new grid feed-in guide-

The newly installed refurbishment department, headed by engineer Gregor Bauer (2nd from left), has a wealth of in-the-field expertise from numerous repair assignments down the years.

Refurbishment & Repair is a new and independent business segment at HITZINGER, opening up new perspectives for old machines. See the before and after effect!

lines.” Basic refurbishments take a few weeks, more extensive refurbs a few weeks more. Whatever the case, the aim is to guarantee rapid refurbishment and minimise system downtimes. The high concentration of profound expertise within the company, and the broad range of in-house production services, enables both standard parts and optimised components to be manufactured in a short time. HITZINGER‘s refurbish-

ment team has not only chosen to focus on its own generators exclusively but to repair and refurbish machines of other manufacturers as well. “The wealth of experience concentrated here means our refurbishment programme can include generators from other manufacturers,” Huber explains, and points out that there has already been a great market response to – and ready acceptance of – this service package.

Focus on core expertise

Since being taken over by the Techco Group, HITZINGER has become noticeably leaner. The airport ground power supply and UPS systems divisions have been discontinued. Both divisions have been removed, enabling the long-established company to concentrate even more closely on generators for hydropower applications, on the railway and navy sectors, and on industry. In Daniel Huber’s words: “We are focussing on our core competencies, supplying customised machines for every type of application. The needs of each project and customer are handled with an individual approach to find the best possible solution, and this is a principle we will continue to adhere to.”

HITZINGER lives up to its well-known company slogan: ‘Power.Anytime.Anywhere.’ As a company that thinks and acts sustainably, HITZINGER is an innovative and competent partner for the provision of clean energy. Decades of experience and Austrian technical expertise guarantee supremely efficient products that produce a reliable and sustainable supply of energy. HITZINGER is back!

HYDRO POWER

Philipp Oberndorfer, Head of Sales in the Hydropower Division at HITZINGER.

Daniel Huber, Managing Director of Technology & Sales at HITZINGER.

CMA HYDRO is a foreign-oriented company which, from the beginning, has always operated throughout Europe for the most important public and private companies in the hydro sector, exporting its expertise. To do so, CMA HYDRO has a branch in France, in Norway and has multilingual personnel. CMA HYDRO has also a significant experience in Austria where it has participated in many large hydroelectric projects (just to name a few: Feistritz, Rodund II, Rellswerk, Obervermund II, Limberg I).

Sand blasting and painting of a spiral case

The company, based in Italy, is highly specialized in mechanical installation of hydro equipment such as turbines, generators, valves, gates, penstocks, piping, etc.

In addition to mechanical installations, the company has an in-house engineering department able to design and supply customized hydro equipment as any kind of hydro valves such as butterfly, spherical, hollow-jet, etc., any kind of gates and stop-logs, penstocks, piping, hydraulic power units and more… (see more details on website: www.cmahydro.com).

CMA HYDRO is able to perform several mechanical activities on-site: from mechanical disassembly and re-assembly of hydro equipment to on-site machining and welding activities, from sand blasting and painting activities to scaffoldings, etc. All these services are provided with high professionalism, reliability and flexibility, satisfying the many needs of its clients who can thus count on a single supplier and simplify the site supplier’s management.

Collaboration with renowned producers of electricity

Over the years, CMA HYDRO has acquired clients from the most important European public utilities, private producers of electricity, turbines / generators manufacturers and mechanical workshops for which the company performs hydro equipment assembly.

In order to meet the growing market demand of specialized manpower and to support its clients in every challenge, from 2022, CMA HYDRO has become a proud member of a permanent consortium company named MECA (www.mecascarl. com), with other companies from the same business sector. MECA combines the strength and skills of their affiliates who, thanks to a common structure, benefit from a mutual strategic organization that manages bureaucratic, administrative, logistical, commercial and promotional needs and give them and the clients a more integrated and competitive offer, as well as more staff available.

For CMA HYDRO, the future is focused on growing collaboration in the European market and building strategic and long-lasting partnerships with its clients and suppliers. This approach has guided CMA HYDRO over the years and continues to be the guiding light.

CMA HYDRO proves expertise in mechanical installation of generators.

An experienced CMA HYDRO team guarantees professional and successful mechanical installation of turbines.

© CMA HYDRO

NEW GRATKORN HYDROPLANT SUPPLIES 15,000 HOUSEHOLDS WITH 100% GREEN ELECTRICITY

Last October the new Gratkorn Mur power plant was officially opened by VERBUND and Energie Steiermark, around two and a half years after the official ground-breaking ceremony. The joint project partners built the plant around 10 kilometres north of the centre of the city of Graz to provide sustainably generated electricity to cover 100 percent of energy demands of around 15,000 households in an average year. Two Kaplan turbines were designed to accommodate a discharge flow of 205m³/s from a head of 6.62 metres, and to achieve a maximum power output in excess of 11 megawatts at full-capacity intake. When speaking at the commissioning ceremony for the green electricity project on the River Mur, having cost them around 100 million euros VERBUND and Energie Steiermark were delighted with the results.

Turbine 1 was turned on for the first time at the end of the construction phase in May 2024. Official commissioning of the new Mur power plant took place on 4th October. High-ranking politicians were joined in Gratkorn in Styria by numerous representatives of the project partners VERBUND AG and Energie Steiermark, and by representatives of various companies involved significantly in the realisation of the run-of-river power plant. In his speech, the former provincial governor Christoph Drexler described the new Mur power plant as a quantum leap for the energy transition in Styria. Michael Strugl, CEO of VERBUND, agreed, referring to an excellent partnership with Energie Steiermark: “We are working at full speed to transform our energy systems. Here in Styria in particular, hydropower plays a key role in renewable energy supply, and the commissioning of the Gratkorn Mur power plant is another building block towards a climate-neutral energy future.”

All good things take time

According to David Oberlerchner, VERBUND project manager for the plant, the first plans for the construction of a run-of-river

The Gratkorn Mur power plant was built by VERBUND and Energie Steiermark within a construction period of 2.5 years to generate an annual average clean energy power output of around 54 GWh.

Bird‘s eye view of the River Mur power plant construction site.

power plant on the Mur were developed over 40 years ago: “In 1981, as part of a phased plan, Austria’s water bodies were assessed in terms of their hydro-energetic potential, resulting in the first drafts for the construction of a new Mur power plant at the Gratkorn site. However, it took more than four decades from the initial plan to the official ground-breaking ceremony for the project partners VERBUND and Energie Steiermark. There were several reasons for this, Oberlerchner explains, but it was primarily due to the economic viability of the project –one that ultimately required an investment of around 100 million euros. Moreover, there were concerns among the local population that the construction of the power plant could affect the local drinking water supply. In Gratkorn demand is primarily covered by a municipal well. “Even though regional water deterioration resulting from a new power plant was extremely unlikely, obviously, the concerns and arguments of the citizens had to be taken seriously,” the project manager emphasised. Consequently, structural precautions were taken to guarantee the municipal drinking water supply and facilitate the connection to a drinking water pipeline running through the municipality.

Bavarian industry experts ensure free flow

The Bavarian hydro industry specialists at Muhr provided a multifunctional articulated-arm rake cleaner to keep the power station intake free of flotsam and jetsam.

The basic structural and technical concept of the new power plant in Gratkorn was consciously modelled on existing plants along the Middle Mur. The new Mur power plant also utilises a three-field weir system. The adjacent powerhouse was fitted with two machine sets and located in Gratkorn on the orographic right-hand side of the river. Each weir field was equipped with hydraulically operated segment gates with flaps attached, each field at a total height of 8 metres and a width of 13.5 metres. Two vertical protective rakes at the intake area next to the weir system prevent larger debris from entering the headrace, while other floating debris is removed by a screen cleaning machine made by Muhr – Bavarian hydro-industry experts. This is a Hydronic system series multifunctional articulated-arm rake cleaner. The rotating and rail-mounted machi-

ne is equipped with a claw to ensure fully automatic cleaning of the protective rake, and transportation of debris from the rake to the collection container. Precise manual collection of flotsam and jetsam is also possible, being executed from a separate driver’s cab. Hydronic M-series rake cleaners also demonstrate their strengths skimming off drifting carpets of floating debris. The safe passage of river ecology also played a key design role for the construction of the new power station. A combined fish migration system was installed to allow aquatic life to pass the transverse weir structure on the way up to the headwater. The fish pass was designed to guarantee the local hucho salmon safe passage, and essentially consists of two parts. In the first section, the fish swim from the tail water area through an artificially constructed basin pass. This ultimately becomes a near-natural channel that guides fish safely into the headwater. In addition, an entire portfolio of measures was compiled within the framework of the green electricity project to maximise the protection of flora and fauna.

Powerful turbines in operation

David Oberlerchner explains the key feature that distinguishes the Gratkorn power plant from other power plants on the River

Mur: “Usually, hydropower plants on the Middle Mur generate electricity via horizontal-axis Kaplan turbines. However, modern calculation methodologies and model testing facilities have enabled the detailed simulation of cavitation behaviour under a variety of operating conditions, prior to power generation – so now turbines can be designed accordingly. The resultant vertical-axis machines can be installed higher up in relation to the underwater level without any efficiency loss, affecting construction cubage and costs positively further down the line.” He added that the decision in favour of vertical-axis machines allowed project management to approach a larger group of turbine manufacturers. Ultimately, following a Europe-wide tender, the contract was awarded to the German turbine manufacturing experts – Kochendörfer, whose concept impressed them by offering both the best value for money, and the best projections for annual power generation. The Graz planning office Prof. Jaberg & Partner GmbH was also involved in the detailed planning and construction of the turbines and was responsibile for the CFD calculations. Moreover, the Institute of Hydraulic Fluid Machinery at Graz University of Technology allowed its test rig to be used to conduct a model test on a scale of 1:13.3.

Green high-voltage grid electricity

Construction site turbine installation was coordinated according to the construction progress of the respective project

elements, so it had to be carried out in several stages. Firstly, in September 2022, the wooden formwork for the two intake manifolds was erected on the foundations of the machine building. In November, the support blade ring was delivered – the first of the extremely heavy turbine components. At a considerable weight of around 28 tonnes, the component had to be manufactured in two parts and could only be fully assembled on site. Delivery of the impellers and guide vanes in the August of the previous year had marked the punctual completion of another project milestone. Turbine 1, like its machine twin, was designed for a design flow of 102.5 m³/s and a gross head of 6.62 m, and was finally started up in April 2024. In single-machine operation and at full volume flow the Kochendörfer turbines achieve a maximum power output of just under 6MW, and in twin-machine operation over 11 MW. These modern turbines can generate electricity efficiently over a wide operating range due to double regulation capability facilitated by adjustable runner blades and the guide vanes, even when the water supply is greatly reduced. Two synchronous generators coupled directly to the runners complete the machine sets. Manufactured in Croatia by Končar, these water-cooled machines run at exactly 107.1 rpm. According to David Oberlerchner, the way the electricity generated at the Gratkorn power plant is fed into the public grid is also unusual: “Normally, plants of this size feed into the 20kV medium-voltage grid. However, at the Gratkorn power plant this would have required the costly

TECHNICAL DATA

Plant typ: run-of-river plant

Flow rate: 205 m³/s

Gross head: 6.62 m

Turbines: double-regulated Kaplan turbines

Turbine axis: vertical

Turbine speed: 107.1 rpm

• Max. output each Turbine: 5.884 kW

Manufacturer: Kochendörfer

• Generator: Synchronous

Voltage: 5.500 V

• Max output each Generator: 6.500 kVA

• Manufacturer: Končar

Annual average production: ca. 54 GWh

The 4-blade impeller had to be lifted precisely.

The three weir sections were equipped with segment gates.

The fish migration system consists of a lower section technical slotted pass, which ultimately merges into a naturalised bypass channel.

construction of an underground power line a kilometre in length. However, by feeding the electricity into the high-voltage line running directly past the new building, a solution that took the shortest route was developed as an alternative. Ultimately, the grid operator approved this option as it also went hand in hand with the construction of a 110 kV outdoor switchgear next to the machine building.”

A milestone for climate protection

After around six months following the start of the trials, the system is now in regular fully-automatic operation. David Oberlerchner offers a thoroughly positive summary of project progress, and the pleasing results: “The power plant has been generating electricity smoothly ever since it was commissioned. Initially, plants of this size and complexity obviously encounter a few teething problems, but these have now been largely eradicated. We can honestly say this project has been, and is, a success. All the companies and people involved deserve major compliments, having distinguished themselves with a cooperative approach and open communication.” There was plenty of praise for the project at the opening ceremony on 4th October, as the plant will generate the power – completely sustainably – to cover the annual electricity requirements of around 15,000 average households. Former Deputy Gover-

The two machine sets consist of Kochendörfer vertical-axis Kaplan turbines and directly-coupled Koncar synchronous generators. Together, at full water supply, the modern turbines can achieve a maximum output of over 11 MW.

nor Anton Lang explained how the project made an important contribution to climate protection: “In recent years, in provincial government we have implemented numerous cross-departmental measures for climate protection. A key to achieving this goal is the massive expansion of renewable energy use, so I’m very pleased the Mur power plant in Gratkorn is another milestone along this road.”

TRASH RAKES AND TRASH RACKS

AUMA CELEBRATES 60 YEARS OF SUCCESS

As a leading global supplier of electric actuators, AUMA looks back on 60 successful years of innovation, reliable partnerships, and growth. In September 2024, the company celebrated its 60th anniversary with more than 3,000 invited guests at its headquarters in Muellheim, Germany. Throughout the day, the guests enjoyed a diverse programme and the culinary delights of numerous food trucks. Visitors saw the modern production facilities on tours of the factory halls. There was entertainment for the many children on the company’s own soccer pitch with a bouncy castle, human table football and lots of games.

“We would like to thank our employees,” said CEO Dr. Jörg Hoffmann and CSO Ferdinand Dirnhofer. “AUMA’s success is the result of many years of hard work, loyalty and a high level of commitment for our customers from all our employees.”

When the company was founded in 1964, it already bore the brand name AUMA and a clear business plan. Armaturen- Und Maschinen-Antriebe – AUMA for short – would become a manufacturer of electric actuators for industrial valves. Werner Riester was responsible for R&D while Rudolf Dinse looked after sales and finance.

“I was always convinced that our company would be successful,” said company co-founder Werner Riester, “but I would never have thought that we

would one day become the global market leader for electric actuators.”

Proven in hydropower

Today, AUMA has over 2 800 employees worldwide and a turnover of more than half a billion euros. For decades, AUMA‘s robust and versatile actuators have been successfully used worldwide in a wide variety of hydropower applications, from all kinds of water level control applications for fish ladders, sluice

gates, weirs, dams, and locks to precise turbine control. In addition, AUMA actuators play a key role in many other challenging applications in water and wastewater management, flood protection, energy generation, the oil and gas industry, and the process industries. Thanks to a global sales and service network with offices in more than 70 countries, AUMA has a strong global presence.

www.auma.com

Enjoying the 60th anniversary celebrations: AUMA co-founder Werner Riester (centre) with the current General Management, CSO Ferdinand Dirnhofer (left) and CEO Dr. Jörg Hoffmann (right).

Visitors explored AUMA’s modern production facilities at its headquarters in Muellheim, Germany.

For decades, AUMA‘s robust and versatile actuators have been used successfully in challenging hydropower applications worldwide.

Metalloid treatment for a Francis turbine exposed to extremely high sediment loads

SHIELDING TURBINES: NEW TECHNOLOGIES FOR WEAR AND CAVITATION PROTECTION

Wear caused by sediment and cavitation remain key issues in hydropower. Despite the common use of state-of-the-art, high-quality steels in turbine production, it’s often not enough to protect components from extreme and enduring hydraulic risks. The renowned Austrian turn-key provider Global Hydro Energy is seeking optimum protection for parts, primarily working with coatings, armouring and reinforcements. For a number of years the specialists have been cooperating with large energy suppliers and university institutes on research to identify various options for the optimisation of turbine protection. This has enabled Global Hydro to acquire broad expertise in now commonplace HVOF coating techniques, high-performance elastomer coatings and state-of-the-art laser cladding processes. In-house engineering and expertise provide the answers.

Immense material stresses occur wherever sediment-bearing water contacts technical turbine components at high speeds. Wear damage is inevitable. This applies in particular to all hydraulically active turbine surfaces. “Massive stress is generated wherever flow velocities are high, water is diverted and where changes of direction take place. These forces act on runners, guide vanes, labyrinth rings, wear rings, turbine covers, wicket gate rings, nozzles, baffle and deflector plates – in short, on all components in direct contact with water with suspended sediments” explains Klaus Eichlberger, Head of Mechanical Engineering at Global Hydro – the Upper Austrian hydropower all-rounders. Eichlberger has been working with his team on runner protection for several years. Protection from wear – but also from cavitation.

Recognising the causes of wear

The main cause of wear is the abrasive effect of solids in the water – like sand, silt and glacial sand particles. In certain regions of the world, such as parts of Asia, there are particularly high concentrations of sediment in the water. In Nepal, effective water treatment via desanding basins would be beneficial in many cases, but geographical and infrastructural restrictions rarely permit this option. A site at 3,000m above sea level would be just one example. As a result of abrasion, regular replacement of runners becomes a necessity since there is no economical means of repairing the wear and tear. Seasonal weather is another key factor. In regions with pronounced rainy seasons, there are always short periods with greatly increased sediment loads. “In our experience, operators some-

times make a conscious decision to switch off the machines temporarily. The financial losses caused by the downtime are considered less significant than the expense of repairs caused by abrasion damage,” Klaus Eichlberger explains.

In addition to the volume of sediments, grain size, grain shape and grain hardness also influence the degree of damage significantly. Global Hydro’s expert refers to the example of quartz sand that has hard and very sharp-edged grains, hence a particularly high potential for causing wear on the affected surfaces of a turbine.

Protection from corrosion and cavitation

The specialists at Global Hydro also focus on protection from corrosion; a particularly important issue for seawater applications. Here, they rely on sophisticated alloys such as duplex and super duplex steels with high PREN values (Pitting Resistance Equivalent Number).

Alternatively or additionally, sacrificial anodes made of standard materials can be used to provide targeted protection for the main components – with very positive results, as Klaus Eichlberger points out: “The emphasis for all of our solutions is on cost-effectiveness for customers. We use high-quality materials particularly in areas subject to heavy wear. Otherwise, unnecessary costs would be incurred without any added technical value.”

Global Hydro has enjoyed considerable success treating runners affected by cavitation, especially when using elastomer coatings.

Analysis and customised problem solving

“A central element of our work is the precise analysis of the respective damage mechanisms. Only when we identify the exact source of stress – whether abrasion, cavitation or both – can suitable countermeasures be taken.” [Klaus Eichlberger, Head of Mechanical Engineering at Global Hydro]

On top of the central issue of abrasion, cavitation also plays a significant role. Especially in the refurbishment sector, where existing conditions such as suction height, pipework or building geometries cannot be changed. If certain machine design parameters are changed, cavitation can become an issue. New turbines manufactured at Global Hydro are always designed in such a way as to avoid the occurrence of cavitation. However, damage risks often increase when compromises have to be made in the conversion of existing turbines.

As Head of Mechanical Engineering at Global Hydro, Klaus Eichlberger is convinced that protection from wear is dependent upon one thing above all others – knowledge. The right questions have to be asked in order to identify professional solutions for each respective application. “A central element of our work is the precise analysis of the respective damage mechanisms. Only when we identify the exact source of stress – whether abrasion, cavitation or both – can suitable countermeasures be taken. State-of-the-art technologies such as acoustic sensors are being utilised in our current research projects, making it possible to analyse flow noise emissions and draw conclusions concerning cavitation and wear. ”This allows us to determine the source of the problem, the nature of the problem – and which solution is sustainable and economically viable,” he says, adding: “Our experience from over 1,000 plants worldwide shows there is no standard solution. Every plant poses unique challenges, be it fine red soil in Vietnam that clogs up valves in a very short space of time, aggressive glacial milk in the Himalayas and even the Alps, or chemical influences in mines. Whatever the case, finding the right strategy for protecting infrastructure always involves a tailored solution.”

A solution for every application

Wear protection in hydropower is a complex but not intractable problem. There is no ‘silver bullet’, no one-size-fits-all offthe-shelf solution. However, sound analyses, proven protective measures, a profound understanding of fluid mechanics and a great deal of experience ensure even the toughest conditions can be mastered. Customised solutions for the problems at hand are precisely what the the Upper Austrian hydropower all-rounder Global Hydro guarantees. State-of-the-art coatings, armouring, optimised materials or a combination of various measures, can all prove to be the right solution. Some components are particularly susceptible to wear, so in certain cases it makes sense to design them as so-called ‘sacrificial parts’ that can be replaced quickly and cost-effectively, outlines Klaus Eichlberger.

In-house research – an important asset

Various coatings have proven to be highly resistant to certain types of mechanical stress. Hard alloys, materials optimised with metalloids and coatings with elastomers, help to extend the operating life of stress-prone components. However, not every coating is suitable for every load. HVOF is a coating based on tungsten carbide that has proven very effective. Nevertheless, although very hard, it’s unsuitable for preventing cavitation. Its brittleness means that the implosion of gas bubbles on the material surface causes the coating to flake off. “Since it is brittle, HVOF coating is also unsuitable where there is a risk of impact from stones,” Eichlberger continues.

Global Hydro has been conducting in-depth research for some time to determine the material properties and coatings best suited to each respective application. An excellent

Global Hydro engineers test various base and coating materials using a wastewater turbine nearby the Global Hydro headquarters.

example is the small wastewater power plant located right next to the company’s headquarters in Niederranna, Upper Austria, which is mainly used for research purposes. The single-jet Pelton turbine installed there is designed to accommodate a head of 250 metres and meet a long list of specifications. According to Eichlberger: “The runner is fitted with a wide variety of buckets made for ease of replacement. They are made of various materials – a range of steels, aluminium, printed materials, titanium and coatings with HVOF or metalloid optimisations. We can test the various options, and analyse them.”

Testing also provides an opportunity to check out specific qualities of HVOF coatings produced by a range of providers. Ultimately, very clear preferences have been identified.

HVOF coating

Tungsten carbide-based HVOF technology has proven its value for highly stressed components in hydropower plants; those exposed to extreme abrasion caused by sediment. “This coating has been the subject of intensive testing and is used to coat both Pelton runners and Francis turbine components. Although it is important to be aware that this type of coating, due to its brittleness, cannot be used in every situation – our experiences with it have been very positive. However, it’s significantly more cost-intensive than others,” explains Eichlberger. In general, HVOF coating is very complex, but Global Hydro is no longer reliant on the expertise of suppliers, and instead identifies its own detailed specifications – such as pre-treatments, precise layer thickness, adhesion and porosity. Global Hydro’s head engineer cites a hydropower project in Mexico as a reference project. One of several 18-MW Pel-

ton runners was provided with an HVOF coating. Up to 16 metric tons of sediment are channelled through the turbines in the power plant per day, dropping from a head of 850m. The sediment consists of highly abrasive volcanic rock. The last few years have shown that the HVOFcoated runner has a significantly longer service life than an uncoated runner from another supplier. Indeed, its operating life has been extended by a factor of 2.5, again demonstrating that HVOF coating is highly resistant to abrasive particles and ensures component surface integrity is retained for a long time.

Elastomer coatings

Elastomeric coatings are particularly suitable for low heads, low flow velocities and high sediment content water.

As the name implies, a decisive advantage of this coating is its elasticity, as it exhibits astonishing resilience to larger particles such as stones and other water-propelled solids. “We coated the high wear effected components of a kaplan turbine to protect them from the aggressive abrasion of sediments and damage from high flow velocities. High speeds required a flexible, resilient coating that tolerates turbulence in the boundary layer area and significantly increases the longevity of the part –and it was an absolute success,” says Klaus Eichlberger, describing a specific application, and also referencing experiences with coatings for Francis turbine runner ducts: “The risk here is cavitation. The elastic properties of the coatings dampen impacts and minimi-

Original Pelton Runner without HVOF – ground by glaciers

New Pelton Runner with HVOF – ready to be mounted

Pelton Runner after one year geometry intact –without any grinding by glaciers. No reducing of HVOF detected

Global Hydro’s experts have also had excellent experiences with elastomer coatings. These have proven highly resistant to both wear and cavitation. The picture shows a model test.

Metalloids

Semi-metallic treatments are a more recent development and involve special thermochemical processes. What sets these new semi-metallic surface coatings apart is the extreme hardness they achieve – up to a degree of 1,800HV, thus making the resulting hard surface extremely resistant to abrasion. In comparison, quartz has a hardness of 800 to 1,000HV. The process is primarily used for runners and wicket gate rings exposed to extremely heavy wear. “Two runners to which we have given semi-metallic treatment are in use with an Upper Austrian energy supplier, whose experience with them so far has been very good,” states Klaus Eichlberger. He also points out additional favourable properties of this relatively new material: “The result of the process is a surface that is only 20 to 40 micrometers thicker, so there is no need for compromises such as roundings in the runner design. Secondly, compared to HVOF, the process is significantly cheaper. Moreover, the technology guarantees a very smooth surface that obviously has a positive effect on the hydraulic properties of the runner.”

Stellite laser cladding

se cavitation damage. Hence, elastomers help to cushion the implosion of gas bubbles during cavitation, and thus prevent the occurrence of material damage.”

The highly resistance elastomer coating is also beneficial in terms of expense, particularly the relatively low cost involved in repairing damaged surfaces. The Global Hydro engineer expands: “Elastomer coatings have proven to be very durable, especially in older systems, such as those fitted with guide and baffle plates – and have shown how the use of elastomers can actually double the working life of components.” However, Eichlberger also cites limitations to this technology as high flow velocities quickly erode elastomer coatings, so elastomers are not ideal for use with Pelton buckets.

Stellites are used for applications where both extreme abrasion resilience and extreme cavitation protection are required. Stellites are hard cobalt-based alloys in which carbide is also formed. They are known to provide excellent resistance, particularly in abrasive environments. The Global Hydro engineer highlights the case of a power plant project in Switzerland. Runners were upgraded with a Stellite laser cladding coating, and this has proven itself to be an outstanding application for Stellites. The power plant is over 70 years old and houses two 14-MW turbines. Having suffered from extreme runner wear for a long time, experts believe the main reason for material damage was the many years of unfavourable inflow to the runners, occurring at an angle of more than 45 degrees. Even HVOF coatings had been used, but the same types of damage were identified again and again – especially on the buckets, most likely due to cavitation. “Almost all of our competitors have tried their hand with an runner for this particular power plant. We also provided a standard runner that had the usual ‚shadow‘ after around six months of operation – the initial sign of runner damage. No matter, we were determined to solve the problem and carried out targeted repair work,” Klaus Eichlberger says. The damaged areas of the runner buckets were milled out of specially selected Stellites was

Special thermochemical processes give this metalloid material enormous hardness, making the surface extremely abrasion resistant. This runner is still in production at the facility of Global Hydro and will undergo further machining and finishing steps.

Laser Cladding on a Pelton Bucket – outside Repair of a damaged Pelton Bucket via Laser Cladding – inside

After 1862 hours in operation, the runner shows signs of wear, but not in the areas repaired with Stellite laser cladding.

applied via laser cladding. The bucket surfaces were then carefully milled again, and polished for an optimum surface finish – a decisive factor for performance. “The results were fascinating,” says Eichlberger. “After 1,862 hours in operation, it became apparent the critical areas armoured with Stellite had remained free of material damage, whereas the areas where Stellite was not applied showed signs of wear – thus demonstrating that Stellite laser cladding can significantly increase the longevity and consequently the long-term performance of turbines.”

Stainless steel cladding is another option Eichlberger mentions. Global Hydro uses its own welding robots, utilising the innovative approach of cold metal transfer (CMT) to apply stainless steel – layer by layer. This guarantees fault-free, uniform, reproducible application using a low heat input not viable with conventional welding processes. Stainless steel cladding is primarily used at Global Hydro at specific points to reinforce nonstainless steel parts with higher-quality materials, and wicket gate rings are cited as an example.

Cladding technology and reverse engineering

One of the questions Global Hydro has investigated is the issue of whether worn runners can be repaired efficiently and cost-effectively using the new cladding technology. The answers have been provided by an ongoing reverse engineering project. “Operators usually have templates and runner drafts, but unfortunately rarely possess precisely detailed runners geometries. Global Hydro has developed special programmes to overcome this problem. The runners are scanned in 3D by the company’s hydraulic specialists, after which the specialised software is used to optimise geometries for improved flow characteristics.” This allows exact differential volumes to be determined and the cladding material to be applied with high precision by the welding robot. The material is applied in several layers during the cladding process. The surface is then milled, ground and polished to create a hydraulically optimised surface. “Once the repair work has been completed, the result is an runner that runs like new and ensures a significantly longer working life,” emphasises Klaus Eichlberger. The customer was delighted. Functionality was restored and repair costs were significantly reduced. The automated process of cladding technology is a unique solution on the market that results

in significant extensions to the working lives of runners – and is far less expensive than purchasing a completely new one.

Recognising sediments via machine learning and AI

Choosing the right coating or type of material optimisation can make a significant contribution to extending the working life of hydropower machinery, particularly under difficult operating conditions. The Upper Austrian hydropower specialists at Global Hydro are now in a position to provide clients with customised, sustainable solutions. However, the company certainly doesn’t intend to leave it at that. “In future, our digital solutions will also enable us to supply software that recognises sediment contamination in advance. The immense wealth of experience and data from our projects is allowing us to work on the achievement of fully automatic sediment detection. Prior to imminent sediment contamination the programme enables an operator to decide – on a case-by-case basis – whether the power plant needs to be shut down,” explains Global Hydro Managing Director Heinz Peter Knass, and adds: “It’s part of the Global Hydro philosophy to develop in-house expertise – in this case in coating technologies, and to strengthen our market leadership in this field. We believe we are in a unique market position, both in terms of the breadth of our product portfolio, and our degree of vertical integration,” and concludes: “For us ‘Everything from a single source’ is much more than just a slogan.”

The welding robot was initially programmed for one cup, with the remaining cups then following automatically.

Worn Pelton runner with clear signs of erosion and loss of performance. Repair welding carried out at the customer‘s request.

Company Headquarters of Global Hydro Group in Austria

AUSTRIAN HYDRAULIC STEEL CONSTRUCTION EXPERTS RENOVATE

BOTTOM OUTLET OF BAVARIAN WORLD HERITAGE POWER PLANT

The refurbishment contract for the bottom outlet of the long-serving LEW power plant in Meitingen on the Lech Canal required the entire expertise of the experienced industry professionals at Braun Maschinenfabrik in Vöcklbabruck, Upper Austria. This certainly wasn’t an everyday job for the experienced hydraulic steel construction experts. It took around seven months to restore 100% functionality to the bottom outlet gate of the weir system. The renovated gate has been back in operation since April of this year, and is now working better than ever.

The completely refurbished bottom bypass outlet gate of the weir system at the Bavarian World Heritage power plant in Meitingen was reassembled last spring. The job presented the engineers at Braun Maschinenfabrik with some tricky challenges.

The old structure was in a poor state. The gate panel was seriously out of shape up at the head and base area under full load, and could not provide a watertight sealing.

The Meitingen power plant on Bavaria’s Lech Canal in the district of Augsburg is much more than just a supplier of green electricity. Run by the Bavarian energy company LEW, the long-serving, conventionally-built hydropower plant is one of the company’s high-performance units – and an acknowledged UNESCO World Heritage Site within the ‘Augsburg Water Management System’. The power plant with three Francis twin turbines was originally commissioned by LEW back in 1922. Remarkably, although multiple upgrades and modernisation measures have been required down the years, the original machine group is still in operation today. The plant symbolises the transition from small businesses to industry, reflects the development of hydropower in the region, and is, hence, of great historical significance – which earned it a place on the World Heritage List.

The consequences of severe corrosion

It’s no surprise that time has taken its toll on the components of this 100-year-old hydropower plant, so, of course, this has also applied to the weir infrastructure. Operational safety at the weir had been guaranteed, but the bottom outlet was now due for total refurbishment, which is why the operators at LEW turned to the Upper Austrian Braun Maschinenfabrik – renowned hydraulic steel construction experts with a long list of references in the field of weir refurbishment.

The order placed with Braun Maschinenfabrik in the summer of 2023 included the revision of the hydraulic system, overhauling the bottom outlet gate and regulating gate, the gate reinforcement, and the reinstallation and commissioning of the overall system. What sounds like a routine order turned out to be a much more complex project. Alfred Mayr (Dipl.-Ing. (FH)), Head of Sales Hydraulic Steel Construction at Braun, explains: “We soon realised the original order volume expected for work would be revised upwards when the two gates arrived at the factory.” It first really became apparent the job would be more comprehensive in the dismantling phase: “When dismantling,

it was no longer possible to unbolt the bottom outlet due to corrosion, so the mounting brackets had to be cut off mechanically, new ones manufactured and then installed.” This was just the first unexpected additional expense the hydraulic steel constructors faced, but more was soon to come.

A leaky gate panel

A high-precision inspection and measurement of the components gave the steel construction experts an overview of the major and minor problems with the gates and their reinforcements. One key point was the deformation of the gate panel, which the engineers at Braun scrutinised more closely via FEA (Finite Element Analysis). Thomas Oberanzmair, an experienced expert at Braun Maschinenfabrik, explains: “The analysis

The main defects in the components came to light after the gate’s protective plates had been cleaned and measured precisely at the Braun factory.

The main guide rails were uneven and the reinforcements were not vertically true.

The gate structure was partially cut open to weld in new beams and stiffening elements.

GERMANY

Braun

Braun

After painting and sealing with anti-corrosion protection, the regulating gate was ready for transport back to Lech Canal.

revealed the panel had never been completely tight in theory or in practice,” and, resultantly, structural recalculation showed that the hydraulic steelwork in the lower part of the bottom outlet gate area needed to be slightly thicker. Oberanzmair expands on the subsequent unexpected additional task: “This forced the team to recalculate the statics completely, and required them to partially cut open the gate structure to weld in new beams and reinforcements.”

The undesirable vibrations made when the gate was being closed were another obvious consequence of the deformation of the gate panel; a problem solved by adding reinforcement.

Imprecisely dimensioned reinforcement beams

Another challenge was posed by the gate reinforcements in connection with the guide rails and sealing surfaces. When inspections were conducted following removal of the gates it became apparent these features also required renovation. On both sides of the gates, Braun‘s technicians identified deviations from the vertical in a double-digit millimetre range. Furt-

The refurbished sealing element is reinstalled.

hermore, the main guide rails for the rollers were very uneven. The main guide rails and, to a lesser extent, the counter-guides, were partially milled away to even out the surfaces, with new stainless steel strips welded on to seal the surfaces. In addition, the concrete immediately alongside the rail had to be cut away to create space for the wheel flange.

“The changes to the geometry of the reinforcement beams necessitated an adjustment to the diameter of the impellers. In concrete terms, this required that all the impellers be remanufactured,” explains Mayr.

Extensive refurbishment programme

Regardless of how extensive the particular specifications became for the engineers at Braun Maschinenfabrik, the hydraulic steelwork components were nevertheless subjected to the usual lege artis refurbishment measures. After dismantling, treatment involved cleaning, sandblasting, surveying and the subsequent assessment of all components, including crack analyses. Once Braun’s own catalogue of measures had been

Meitingen World Heritage power plant

The plant in Meitingen is the third and ‘youngest’ of the power plants on the Bavarian Lech Canal north of Augsburg. It was commissioned in 1922 by LEW, the local energy company, and is still operated by LEW today. Initially it was used to generate electricity for industrial production, then for the people of the region. The high dykes on the Lech Canal rise to a height of around 8 metres in this area and enable the plant to utilise a drop of 13.4 metres. Three Voith-manufactured Francis twin turbines with an installed expansion capacity of 11,460 kW drive three generators (AEG), whose generator coils were last replaced in 2016. The Meitlingen power plant is the only power plant on the Lech Canal still operating today with its original technical infrastructure. The listed infrastructure has been part of the ‘Augsburg Water Management System’ UNESCO World Heritage Site since July 2019. It generates around 83 million kilowatt hours of clean electricity every year.

Meitingen power station on the Lech Canal is a UNESCO World Heritage site in operation using machinery from the time of its construction in 1922.

© Braun

Braun

drawn up, the next step was to implement those measures required and requested by the customer. This was followed by pre-assembly of the gates at Braun’s plant in Vöcklabruck and the application of anti-corrosion protection. After transporting and reassembling the regulating gate to the bypass channel it was time for a variety of function tests. In principle it was a comprehensive pa-

ckage of measures that the Upper Austrians were able to implement in their usual manner, but the numerous supplementary tasks made the customer’s original schedule for system completion and re-commissioning in December unviable. Braun Maschinenfabrik’s experienced team of hydraulic steelworkers was ultimately able to agree an extension with the customer until April, when

Innovations for hydropower

the completed infrastructure was finally handed back to the customer and the bypass was able to resume regular operations.

First address for hydraulic steel construction

The Vöcklabruck company’s experienced hydraulic steelworkers were of course delighted to be able to add this problematic project to their long list of references, and were even more pleased with the praise and positive feedback from the client. They were thanked personally for their excellent cooperation and for the “successful implementation of what was by no means a run-ofthe-mill order.” The refurbishment of the empty passage at the World Heritage power plant in Meitingen again showed that Braun Maschinenfabrik is one of the very best ports of call in European hydraulic steel construction – especially for unusual challenges. In a field as important as hydraulic steel construction it is the difficult tasks – ones that require profound expertise, experience, sensitivity and a sense of responsibility – that reveal which companies are truly up to the challenges.

The entire Braun Maschinenfabrik team demonstrated its expertise in the renovation of the bottom outlet.

© Braun

NEW SMALL-SCALE HYDROPOWER

PLANT

IN VALLE D‘AOSTA GOES ONLINE IN SPRING 2025

A brand-new small-scale hydropower plant has been generating clean electricity on the Saint Barthélemy stream in Aosta Valley, Italy, since spring 2025. The diversion power plant offers a generation capacity of around 3.5 GWh, and the construction team succeeded in reconciling technical power generation requirements with aquatic ecology concerns. The machine building at the plant was constructed completely underground to preserve the landscape, and houses a vertical-axis Pelton turbine with a bottleneck capacity of just under 400 kW. A ‘Grizzly’ Coanda was installed at the water intake – a tried and trusted system built by the South Tyrolean industry specialists at Wild Metal. A vertical slot pass was fitted to ensure safe and smooth passage for fish. The patented system draws in water at a rate of maximum 1,000 l/s and ensures optimum sediment filtration.

The northern Italian municipality of Nus in Aosta Valley has a population of just under 3,000, and is particularly wellknown among wine connoisseurs for the local Vien de Nus grape variety. The large number of hydropower plants in the valley reflects the fact the alpine topography of the idyllic region provides ideal conditions for the water-driven generation of electricity. Located on the Saint Barthélemy mountain stream, it’s one of the most recently-built small hydropower plants in the Aosta Valley. The project, implemented by the power plant company Soc. Idroelettrica St Barth Alto srl., was completed in spring 2025.

Combined hydropower plant and irrigation system

Ing. Alessandro Mosso, together with Blu Energie Srl, was responsible for general project planning, and explains that the initial construction concept for the new power plant had been drafted almost 20 years ago: “The first licence application for the project was submitted in 2007. Numerous revisions and optimisations were necessary over the years to ensure compliance with legal regulations and enhance the plant’s energy efficiency. The existing irrigation infrastructure for agricultural land in the project area had to be incorporated into the functional

concept of the hydropower plant to minimise the environmental impact of the project and maximise the hydraulic efficiency of the power plant.” The planner explained how power plant construction contributed to optimisation of the agricultural irrigation system, and thereby to achievement of regional sustai-

Lifting the generator into the underground machine building at the new Saint Barthélemy small hydropower plant.

water intake Coanda system during installation

At a length of 1.6km, the penstock consists entirely of DN800 steel pipes.

nability goals. As regards to the project planning phase, Mosso told of how the approval process had been complex and had lasted more than a decade, having also included several project reviews, hydraulic and ecological impact investigations and environmental impact assessments. Ultimately, the solution agreed met both structural and ecological requirements.

Construction commences in the summer of 2022

The project implementation phase finally started in July 2022. The altitude of the overall project site was between around 1,480m and 1,650m above sea level, meaning primary work had to be carried out between the spring and autumn months. Due to the risk of avalanches, construction work had to be interrupted during the winter months. According to Alessandro Mosso, the unstable geological conditions posed a major challenge for construction. As a result of the conditions the contractors were required to carry out reinforcement measures on the plant structures and the penstock. The latter is 1,622 metre long and, in sections, navigates very steep terrain, hence needed to be reinforced with concrete anchor points. The power descent is made entirely of robust DN800 steel pipes that guide the water as it drops around 160 metres. Furthermore, a fibre optic cable was installed along with the penstock to facilitate digital

communication between the water intake technical systems and the power station control centre. In addition to the penstock for the hydropower plant, a connecting pipe was also laid to feed the agricultural irrigation system. At approximately 950 m long the pipeline also consists of steel pipes, this time DN150-dimensioned conduits.

Innovative water collection system with a self-cleaning function

At the water intake the project operators installed the innovative ‘Grizzly’ Coanda system, built by the South Tyrolean hydraulic steel construction experts at Wild Metal GmbH, where headrace water is diverted. Essentially it’s a virtually self-cleaning patented protective screen system that has proven its practical suitability hundreds of times across the Alps. Water passes through fine screen gaps of just 0,6 mm. The eponymous Coanda effect automatically flushes flotsam and debris from the screen surface. Positioned above the fine screen, reliable protection is provided from coarse floating debris like branches and rocks by a hot-dip-galvanised steel grid. Once the headrace water has been discharged through the Coanda system, it enters a desanding basin in which fine sediments from the headrace water settle slowly before the water flows

TECHNICAL DATA

Flow rate: 1,000 l/s

• Net head: 159,11 m

Penstock: 1,622 m

• Ø: 800 mm

Turbine: 4-nozzle Pelton

• Turbine axis: Vertical

Tubine speed: 600 rpm

Maximum Output: 1,305 kW

Generator: Synchronous

Maximum output: 1,500 kVA

• Annual average production: ca. 3.5 GWh

South Tyrolean Wild Metal GmbH’s patented ‘Grizzly’ Coanda system ensures fully automatic water discharge.

The vertical axis generator is directly coupled to the turbine runner

© Wild Metal

© Alessandro Mosso

Installation of the 4-nozzle Pelton turbine

into the penstock. As well as the ‘Grizzly’, Wild Metal GmbH also supplied the rest of the hydraulic steelwork equipment for the weir system. This included the desander basin flushing flap, various shut-off and regulating devices, and the fully automatic hydraulic control unit for the gates. Ecological waterway continuity was guaranteed by a vertical slot pass built to guide the fish from the tailwater – up past the weir system to the headwater.

Powerful underground machine set

Visual impact on the landscape was minimised by constructing the turbine machine building completely underground. The centrepiece of the well-hidden plant control centre is a 4-nozzle vertical-axis Pelton turbine that drives a generator directly coupled to the runner. The machine set was supplied by Tamanini Hydro The turbine generates 398kW of maximum power at full water supply from an expansion water volume of 1,000 l/s and a net head of 159.11m. The multi-nozzle design enables the machine to operate effectively across a wide range of inflow volumes – and is highly efficient, even when inflow is greatly reduced. The machine set is completed by a 3-phase 1,500 kVA nominal apparent power synchronous generator. The 3-phase air-cooled generator was manufactured by Marelli Moto-

Working at maximum capacity, the machine set generates almost 400kW of maximum power.

ri and was designed for an operating voltage of 3,000 V. The entire electrical and control infrastructure for the powerhouse was also supplied by Tamanini Hydro. Electricity production at the plant is a fully-automated state-of-the-art arrangement, which can be monitored and operated remotely around the clock using a secure online connection. The plant control setup includes an intuitive visualisation system that provides a clear and simple overview of all the most important information pertaining to the current status of the power plant.

Feeding into the grid since spring 2025

In spring 2025, following completion of construction work, the new Saint Barthélemy small hydropower plant finally produced its first load of green electricity – which was fed onto the public grid via a newly installed approximately 3.5-kilometre underground cable. The project’s general planner, Alessandro Mosso, was absolutely satisfied with the final result: “Initial tests have already shown that the new electromechanical equipment is highly efficient. I am sure the power plant is going to give the operators a lot of pleasure in years to come.” The plant in Aosta Valley was built and completed in exemplary fashion, and in an average year it is expected to generate around 3.5 GWh of green electricity.

© Alessandro Mosso

© Alessandro Mosso

EUROPEAN TECHNOLOGY BRINGS HAPPY ENDING TO ALBANIAN POWER PLANT IN NEED OF RENOVATION

The Albanian Stranik power plant was in operation for over a decade with inferior electromechanical equipment. In 2024, the plant was completely modernized and equipped with new machines. This increased the average output capacity by around 20 percent.

It was a mess right from the start. Describing the Stranik hydropower plant in Albania as a “Monday plant” falls short of the mark. Throughout its existence - the plant was commissioned in 2013 – the installed electromechanical equipment from China functioned more poorly than well and could only be operated at the lowest level in recent years with massive humanresource allocation. But this era is over. The majority owner from Austria commissioned the Carinthian hydropower specialists from EFG Turbinenbau and Schubert CleanTech from Lower Austria with the total refurbishment of the power plant‘s electrical equipment, which was completed in just a few months in 2024. The result is simply astounding: Not only does the power plant now run fully automatically like clockwork. In addition, the average output has been increased by 20 percent.

The joys and sorrows of the Draxler family‘s two Albanian power plants were only a few kilometers apart. In the early 2010s, Salzburg lawyer and hydropower entrepreneur Dr. Peter Draxler, who died in 2017, invested in two small power plants in the Western Balkans. He was impressed by the legal, economic and hydrological conditions in Albania at the time. Together with two partners from the region, he invested in Hidroinvest Shpk, in which the Salzburg native secured 80 percent of the shares. As an experienced investor and hydropower expert, Draxler was aware that one point was particularly important and explained in 2014: „With a project like this, it‘s important to have a local partner on board. Especially if something unexpected happens, you can quickly get into trouble without a local partner.“ Nevertheless, he took the flight to Tirana almost every month and then the three-hour drive to the district of Librazahd, not far from the Macedonian border, in order to be able to follow the implementation of the two power plants at close quarters.

Machines a problem right from the start

To his regret, Draxler was only able to contribute his hydropower expertise to one of the two power plant projects on the Radicin River: the Zall Torre hydropower plant, whose power plant equipment, both electrical and control technology as well as electrical machinery, was implemented by renowned Austrian industry professionals. Unfortunately, this was not possible for him at the upstream Stranik power plant. He said at the time: „Unfortunately, the contracts with the Chinese supplier were already signed and sealed when I joined the Stranik project. If it had been possible, I would have canceled it. Unfortunately, the machines were a disaster right from the start.“ Nevertheless, the power plant was kept in operation with this equipment for another 10 years.

After the death of the self-confessed hydropower enthusiast, Peter Draxler‘s son Florian took over the management of the company, although he inevitably had to deal with the growing technical problems of the Stranik hydropower plant

in recent years. In the end, he came to the conclusion that things could no longer go on like this. He commissioned the experienced hydropower specialists from EFG in Feldkirchen, Carinthia, to carry out a precise operational measurement on site. The key questions: What is the efficiency? What expansion potential is possible with modern technology? What is the current status quo?

Technology as it was 50 years ago

In April 2022, Martin Goldberger, junior manager at EFG, set off for the power plant in Albania together with EFG technician Matthias Eberhard. The picture they saw there exceeded the already gloomy expectations of the two experts. „If you apply the standards of a modern hydropower plant, then nothing was working properly here. The power plant was manned in shifts and the staff synchronized and regulated the water levels by hand. They used a camera to estimate how much water was entering the intake and the level was regulated in this way,“ explains Martin Goldberger. The performance of the machines was also disastrous, as the Head of Technology at EFG, Gero Pretis, confirms: „With a design of 2.4 MW, the machine sets could be operated up to around 2.2 MW before the bearing temperature rose to alarming levels and vibrations became noticeable. Our evaluation showed that the machines never reached the specified optimum point. This also made it clear that the basic design was not correct in terms of fluid mechanics.“

A closer inspection later revealed that the sealing elements and the generators, for example, were technically completely outdated. “These components were built like this 50 years ago,” explains EFG Managing Director Werner Goldberger. He also points out that the control technology also supplied by the Chinese manufacturer no longer worked. There were no spare parts, not to mention any kind of support from the manufacturer. In addition, the system documentation was missing and certain defects ultimately even had to be classified as safety-related.

All plans redrawn

The refurbishment project presented by the Carinthian hydropower experts impressed Florian Draxler, who awarded EFG the refurbishment contract in the fall of 2022. “The only thing that helped here was to wipe the slate clean – and reorganize the power plant in terms of the electrical and control systems,” says Werner Goldberger. Ultimately, only the connecting flange of the penstock was to be retained, while the intake

manifold, turbines, generators, control technology, hydraulics and shut-off valve for E&M, as well as the hydraulic steelwork equipment, were redone.

However, the confidence of the engineers from Carinthia in the few available plans from the Chinese original equipment manufacturers was very limited. „For this reason, another EFG team, led by our experienced technicians Armin Pretis & Michael Bader, traveled to the power plant to create a wellfounded natural dimension survey. On this basis, our engineers were able to redraw the construction plans and completely redesign the machines,“ recalls Martin Goldberger, who, as overall project manager, was responsible for transportation and customs formalities in addition to the logistical tasks and coordination with other companies – quite a challenge.

Sophisticated machine design

The type of machines to be used was not entirely clear at the beginning. „Once we had taken a closer look at the structure of the powerhouse, it became clear that basically only two identical Francis turbines could be installed here. The distribution pipeline was integrated into the powerhouse foundation. If that had had to be excavated, the entire powerhouse would have had to be replaced,“ says Gero Pretis. The challenge for the experienced machine designers was therefore to design machines that basically had the same design data as the old ones, but without their mechanical and fluidic deficits. “Our

Approval of the new Francis spiral turbines for the Stranik power plant at the EFG plant in Feldkirchen with representatives of Hidroinvest. Far right: Chief technician DI Gero Pretis.

The exterior of the very generously designed machine house was spared from the conversion work.

The old machines from China had serious deficiencies in their fluidic design – and therefore also catastrophic efficiency levels.

considerations ultimately led us to a Francis turbine with a very low specific speed, i.e. a radial runner with 17 blades and very narrow flow channels,” explains the turbine engineer. The focus was on optimizing the partial load efficiency on the one hand, but also on finally achieving top efficiencies in the peak load range up to 5 MW output on the other. „Ultimately, we succeeded very well. Especially when you consider that the old machines could previously only be operated with an output of 500 kW or more – and with catastrophic efficiency. The new turbines, on the other hand, can still remain connected to the grid down to 50 kW single machine load and even lower.“

Game over for old control technology

Not only the EFG team had the green light to continue with the project, but also the industry partners with whom the Stranik hydropower plant was to be led into a new era. First and foremost was Schubert Cleantech, which was entrusted with the electrical and control engineering side of the project. In detail, the scope of the contract included the entire control and regulation of the plant, including the SCADA system for the power plant, intake and surge chamber, as well as the DC and AC power supply, protection and synchronization, the 6kV gene-

rator cabling, the engineering for the 40.5kV medium-voltage switchgear and the entire plant cabling, including new cable routes. „Essentially, we also had to remove the old, dysfunctional technology from China and replace it with modern European technology. A not insignificant challenge for our team was that the existing plant concept was already outdated when it was built. It not only had to be brought completely up to date, but also adapted to the current requirements – resulting from the new machine equipment and the desired operational management. In addition, there was virtually no plant documentation,“ explains Christian Schwarzenbohler, Head of the Energy Generation Division at Schubert Cleantech.

Communication between the plants

In the case of the Stranik power plant, it was not only Schubert Cleantech‘s excellent reputation that spoke in favor of its involvement. In addition, the company from Lower Austria had already earned an excellent reputation 11 years ago for equipping the downstream power plant Zall Torre, which was equipped with Austrian technology at the time. Werner Goldberger comments: „The operating team on site has experienced first-hand how well the Zall Torre hydropower plant has wor-

The control system of the old plant was in a disastrous state. The Schubert CleanTech team brought the system back up to date by implementing a modern control and regulation system.

The Schubert CleanTech technicians also provided support for the engineering and design of the new 40.5 kV switchgear.

The commissioning of the new machines was a success. Satisfied faces among those involved.

© Troyer

© Schubert Cleantech

© Schubert Cleantech

With the new technical equipment from Austria, the Albanian power plant Stranik can now look forward to profitable times. Proving their teamwork qualities: Werner Goldberger (EFG), Christian Schwarzenbohler (Schubert CleanTech), Martin Goldberger (EFG) and Florian Draxler (Hidroinvest)

ked over the years – and how miserably the upstream Stranik power plant has performed in comparison. For this reason, the plant management expressed a desire for Austrian hydropower technology in the run-up to the refurbishment.“

For the Schubert CleanTech technicians, this was of course an advantage, as communication for the operational coordination of both plants was to be realized in the course of the new automation – and thus there was no interface issue. “Of course, we also incorporated the usual functions that are state of the art in a hydropower plant today,” says Christian Schwarzenbohler. The Schubert CleanTech team also provided assistance with the design and engineering for the 40.5 kVA switchgear, which Hidroinvest commissioned from an Albanian manufacturer.

Side effects of a foreign assignment

In general, the Austrian companies are very satisfied with the handling and, above all, the partnership-based cooperation, which made many things easier. „Of course, the question arises during such a foreign assignment: what tools and machines do you take with you? This goes hand in hand with customs clearance issues – and of course expensive tools should also be returned. That‘s why we got together with Schubert and found solutions on how we could best use tools together. And that worked out wonderfully in the end,“ says Martin Goldberger. He points out that the precise planning for the assembly work in particular has led to a previously unattainable level of organizational discipline. „You really have to plan at home exactly what you want to take with you. Because – unlike a job on your doorstep – I don‘t immediately get every screw or every tool in Albania. I wish we could also demonstrate this planning efficiency on assignments here in Austria. It must also be our standard.“

One fifth more electricity yield

After the old plant was shut down at the beginning of July 2024, EFG and its partners needed just four months before the new power plant was commissioned at the end of October.

„There wasn‘t much water available for the commissioning work at that time, but still enough to carry out all the necessary tests. Like so many things in this project, we also implemented the commissioning hand in hand with Schubert,“ explains Martin Goldberger. The system was put into trial operation on November 5, 2024. The new machines now offer a completely different performance to their predecessors, and comparisons are drastic. In line with the current state of the art, the machine sets from Austria are whisperquiet and extremely smooth-running, which naturally has a positive effect on their longevity. Added to this is the considerable increase in efficiency, which has manifested itself in a noticeable increase in production right from the start. “The machines easily achieve the targeted yield increase of 20 percent,” explains Martin Goldberger.

An example of European engineering

When asked whether the dismantled machine sets from the old stock could possibly be reused somewhere, the experienced hydropower expert Werner Goldberger answers in the negative. They would only have scrap value. „The Stranik power plant is a prime example of how inferior replica machines from the Far East can reduce the value of a hydropower plant – and how solid and strong European quality technology in hydropower is in contrast. We should not forget in such power plant projects that the machines from our latitudes also have a very high vertical range of manufacture, which of course also means added value,“ says the EFG Managing Director. For the Carinthian hydropower specialists, who are completely satisfied with their work in Albania, their involvement in the Western Balkans certainly seems to have paid off. Not least because of the excellent feedback on the Stranik power plant project, the next assignment in Albania is apparently already on the horizon.

TECHNICAL DATA

Net-Head: ~155 m

Turbine: Francis-Spiral

Number of Turbines: 2

Runner Speed: 1‘000 rpm

Output: ~2‘500 kW

• Number of Runner Blades: 17

• Manufacturer: EFG Turbinenbau

• Output total: ~5 MW

• Generator: synchronous

Manufacturer: Hitzinger

Cooling: Water cooled

Control Technology: Schubert CleanTech

Increase in Annual Production: ~20%

Recommissioning: 11/2024

OSSBERGER TURBINE PRODUCES GREEN ELECTRICITY AT WHITEADDER RESERVOIR IN SCOTLAND

An exemplary hydropower project was completed at Whiteadder drinking water reservoir in Scotland shortly before the end of the year. Installation of siphon technology has now enabled excess water from the reservoir to be drawn over the top of the dam and be used to generate electricity. Scottish Water, the power plant operator, believes this concept is the first of its kind in Europe. The electricity generated in the new small-scale hydropower plant is used directly on site for the local Hungry Snout pumping station – one of the largest of its type in the East Lothian region. Ossberger, German hydropower specialist, supplied all of the electromechanical and I&C equipment for the new small-scale power station. The powerful crossflow turbine is designed for a maximum capacity of almost 200kW, and now enables Scottish Water to offset around a third of the pumping station’s annual energy requirements with locally generated green electricity.

The construction of the new hydroelectric power plant at Whiteadder Reservoir was necessitated, basically, by the enormous rise in electricity costs – a development to which the United Kingdom has also not been immune in recent years. From an environmental perspective, the project also boosts the efforts of Scotland’s largest drinking and wastewater mover, Scottish Water, to tap the potential of the unused renewable energy in its extensive hydro-infrastructure portfolio. Scottish Water Horizons, a subsidiary of Scottish Water, identified this expansion potential by conducting a study analysing hundreds of sites across the country – including sewage treatment plants and reservoirs, and thousands of kilometres of drinking water and wastewater infrastructures.

Hungry Snout feeds on hydroelectric power

The study revealed Whiteadder Reservoir in the region of East Lothian to be one of the most suitable sites for the construction of a new small hydropower plant. The reservoir was originally constructed between 1964 and 1968 as an earth-filled dam to expand the region’s drinking water storage capacity. Actual drinking water treatment takes place at Castle Moffat Water Treatment Works, where the water is pumped through Hungry Snout, one of the most powerful pumping stations in East Lothian. The plant transports an average of 32 million litres of water from Whiteadder Reservoir to consumers around the region, and all the way up to Scotland’s capital city – Edinburgh. Construction of the new small-scale hydropower plant has meant that now almost a third of the pumping station’s energy requirements can be covered by locally generated green electricity.

Siphon system and hydropower plant combination

According to Scottish Water Horizons, the operating principle of the new hydropower plant in East Lothian is unique throughout Europe. Water is siphoned up a channel from the reservoir via pump-and-siphon technology, then fed into the new turbine building for electricity generation purposes. The siphon system is equipped with a vacuum pump that implements suction-induced water flow. Hydrostatic pressure guarantees an automatic supply of water from the reservoir. There are obvious advantages to this system – from structural, economic and ecological standpoints. The design chosen avoids the expense of conversion work on the dam structure – making overall

The green building houses the modern hydroelectric technology for the new small hydropower plant at Whiteadder Reservoir.

The penstock can also be used to drain flood water from the reservoir during heavy rainfall.

implementation cheaper. Similarly, this solution left a low CO2 footprint during construction, and the hydropower project has also contributed to flood safety at the plant. Heavy rainfall can trigger flooding, so in such an event the penstock can be used for the targeted removal of water from the dam. In emergency discharge mode the extracted water bypasses the turbine through a pipe. Another benefit of the hydropower project has been an improvement in grid stability. The energy delivered to the pumping station by the small hydropower plant has boosted and stabilised energy availability from the local power grid significantly.

A powerful and robust turbine

The entire electromechanical and I&C equipment for the new small hydropower plant was supplied by the German hydropower specialists at Ossberger, from whom the original Whiteadder Reservoir plant concept also originated. “The project was finalised by Scottish Water Horizon, and various hydro-industry companies were commissioned to carry out planning and construction work. Ossberger supplied the centrepiece of the plant – a crossflow turbine – whose robust technology has proven its worth over 10,000 times worldwide,” explains Julian Jones, Ossberger’s representative for Scotland. The design of the turbine was kept simple very consciously, having only three moving parts, while providing power reliably and coping excellently with fluctuating inflows. This was facilitated by installing two cells inside the turbine to operate independently of each other. The smaller cell only needs 5 per cent of the ex-

TECHNICAL DATA

Flow rate: 1.2 m³/s

Ned head: 25 m

• Penstock: ductile iron Ø: 800 mm

• Turbine: Crossflow Turbine Turbine axis: Horizontal

• Turbine speed: 471 rpm

Maximum Output: 199 kW

• Manufacturer: Ossberger Generator: Asynchronous

• Annual average Production: ca. 820,000 kWh

pansion water volume to generate electricity via the turbine. For the new power plant at Whiteadder Reservoir, Ossberger supplied a turbine designed for a discharge rate of 1.2 m³/s and a net head of 25 metres that achieves a maximum output of 199kW at full load. Finally, the electrical infrastructure and control equipment completed the scope of delivery to ensure fully automatic plant operation.

Green power role model

Julian Jones cited compliance with the strict safety criteria, statutorily required for all structural changes in the dam area, as the biggest challenge faced during the approximately twoyear phase of implementation. Special precautions had to be taken at several sites around the project area to ensure personal safety and structural integrity – as was the case for diving work and construction activity on the embankment. The new small-scale hydropower plant at Whiteadder Reservoir began producing electricity in December 2024, roughly two years after construction originally commenced. “The complexity of integrating a siphon system combination meant we were still busy with various fine-tuning tasks a long time after initial commissioning. Just a few months after completion, in automatic mode the power plant is producing a regular yearly average of 820,000 kWh energy reliably and efficiently,” says Julian Jones. Scottish Water is very pleased with the final result of this exemplary reference project in East Lothian and sees it as a further step towards achievement of the company’s environmental goals.

The Ossberger crossflow turbine achieves a maximum output of almost 200 kW.

The siphon system supplying the power station is located next to the dam.

PELFA GROUP DEMONSTRATES LARGEHYDROPOWER MANUFACTURING COMPETENCE

2024 has been a year of exciting activity for the PELFA Group, which has its headquarters in Udine in northern Italy. A comprehensive expansion of their range of machinery has allowed the eminent hydropower specialist to elevate their manufacturing portfolio to a whole new level. Numerous international contracts have also been pouring in, feeding their pipeline with projects from Slovakia to Norway and Kyrgyzstan. With their new machinery and the technical know-how of their well-coordinated team, the steelwork engineering specialists are confident to reinforce their position as a reliable manufacturing partner that will continue to extend the frontiers of technology.

PELFA’s service portfolio covers the entire steel engineering production process, from order acceptance to delivery of pre-assembled, ready-to-install components. The company’s sustained success is rooted firmly in their wide-ranging technical expertise in steelwork engineering. All manufacturing steps – including plasma cutting, welding, bending, CNC milling, corrosion protection and final assembly – are performed at the same central production site. PELFA’s expert engineers, many of whom are former apprentices, are a core element of the corporate strategy and the company’s most valuable success factor.

New machines on the block

By extending their range of machinery equipment in 2024, the PELFA Group was able to further grow their manufacturing capacity as well as their portfolio of integrated high-end solutions. The new equipment includes a bending press delivering 2,000 tonnes of bending force, a 3D laser scanner with a 0.2 mm precision rating, and a Series “integrex E500H II” CNC lathe by Mazak. In addition, the existing Pama brand boring mill is currently completely revamped. Throughout 2024, PELFA’s consolidation of their optimised manufacturing workflows also attracted a lot of orders, which are now being implemented step by step. Current key projects include the manufacture of two DN4000 butterfly valves for the Kühtai 2 pump storage power plant in Tyrol. Weighing up to 70 tonnes each, the two valves are designed to withstand up to 15 bars of pressure and are manufactured, painted, assembled and tested by PELFA. Other PELFA equipment for the Kühtai 2 facility include the valve bodies for the spherical valves. For the Ruzin hydropower station in Slovakia the Italian specialists are manufacturing four new DN4450 butterfly valves with a PN10 pressure stage and a weight of up to 60 tonnes. Another contract awarded to PELFA last year is for a Norwegian hydropower station. The Jukla facility is scheduled to receive new valve bodies for spherical valves weighing approximately 9 tonnes. A further recipient of PELFA equipment is the new Kulanak large-hydropower plant in Kyrgyzstan: following the factory acceptance test, four new

Strengthening customer partnerships

According to PELFA, their customers particularly appreciate being able to rely on the comprehensive technical and logistic support if and when they need it. Among other things, these services include the final assembly of components, ac-

DN3500 PN10 butterfly valves will be sent on their way to central Asia.

New DN4450 butterfly valves for the Ruzin hydropower plant in Slovakia

Butterfly valve for the new Kühtai pump storage power plant

ceptance testing and on-site delivery of the pre-assembled components. Since 1979, when the PELFA Group was founded by Redento Fabbro, the company has established itself as a reliable manufacturing partner for a wide range of industrial applications. As managing directors Andrea Forgiarini, Daniele Fabbro and Alessandro Bertino explain, this approach is to be extended further, considering its clear benefits for both PELFA and their customers. This will enable the integration of efficient manufacturing methods while allowing the engineers to react flexibly to special technical requirements for testing and installation, all in close cooperation with the plant operators. By following this strategy, the PELFA Group intends to further underscore their position as leading innovators and providers of comprehensive service. At the same time, the company will continue to reinforce their partnerships with its industry-based customers by providing them with precision-tailored, technically advanced solutions.

Production of a new valve body for the Jukla hydropower plant

Valve body for the Kühtai power plant during production

REPOWER CELEBRATED ITS 120TH ANNIVERSARY

Repower‘s history began in 1904 with the construction of a hydroelectric power plant in Campocologno. Hydropower remains at the heart of Repower‘s strategy to this day. Repower is the only energy company in Graubünden to be active along the entire electricity value chain. In its anniversary year 2024, Repower published the highly recommended book “Strom Werke Menschen – 120 Jahre Repower”. The book deals with questions such as why Europe‘s largest high-pressure hydropower plant was built in Valposchiavo 120 years ago, why the construction of the Küblis power plant led to one of the most momentous economic debacles in the canton of Graubünden and why the company was managed by one family for over 80 years.

The history of Repower begins in the very south of Graubünden - in Valposchiavo. The company was founded on June 14, 1904, at that time still under the name Kraftwerke Brusio (KWB). The first high-pressure power plant with Lago di Poschiavo as a reservoir and the headquarters in Campocologno was the largest of its kind on the continent when it ope-

ned. The electricity produced was initially mainly exported. Far from the Swiss consumer centers, Valtellina and Milan were the main customers. From 1908, KWB supplied electricity for the electrification of the private Bernina Railway and later also the Rhaetian Railway. After the Second World War, more and more electricity was supplied to the north via the Bernina Pass.

Close ties with Italy

The company experienced its greatest expansion in 2000, when KWB merged with the Rhaetian Works for Electricity and Bündner Kraftwerke AG to form Rätia Energie AG. Ten years later, the company was renamed Repower. The impetus for the merger in 2000 came from the canton of Graubünden, which had acquired the shares in Bündner Kraftwerke AG from Nordostschweizerische Kraftwerke AG (NOK) three years earlier. In 2004, the group was expanded to include aurax ag, based in Ilanz.

The close connection between the company and Italy that was established in the early days still exists today. Rezia Energia Italia was founded in Milan in 2002 (Repower Italia since 2010). In addition to its sales activities in Switzerland and Italy, Repower is now present in the most important Central European trading centers through its trading locations in Poschiavo and Milan.

Electricity has been produced at the Küblis Hydropower plant in the canton of Graubünden since 1921. Picture: The construction of the penstock.

Repower

The history of Repower began in 1904 with the construction of the Campocologno power plant.

Repower

IMPRESSIVE INNOVATIVE TECHNOLOGY AT NEW RESIDUAL HYDROPOWER PLANT IN AUSTRIA

An innovative DIVE-COAX Turbine without a powerhouse was installed to generate electricity from the water diversion in the Obersulzbach. The machine set produces around 1 million kilowatt hours of electricity per year.

Salzburg AG, an Austrian energy supplier, is currently constructing a new small hydropower plant on the Obersulzbach River in Neukirchen am Großvenediger in Austria to go into full operation this year. Three turbine variants are to be used for electricity generation at the Sulzau power plant. The residual water turbine, the smallest of these, is particularly technically innovative. The entire DIVE Turbine-Generator-Unit was installed in a vertical 20-metre penstock. The system was hydraulically optimised for this purpose to generate around 1 million kilowatt hours annually.

The Sulzau power plant project site is located in the idyllic Obersulzbachtal valley in Austria‘s Pinzgau region. Construction work has been underway since April 2023 and the plant is scheduled to go online punctually in the first half of 2025. Salzburg AG and Lichtgenossenschaft Neukirchen are jointly investing around 23.5 million euros in a plant expected to supply around 18.4 gigawatt hours of clean electricity in an average year. The new green­energy set­up is one of the smaller of such infrastructures in the Salzburg energy supplier‘s hydropower plant portfolio. However, technologically, it has a lot to offer – with a larger­scale Francis turbine, and a smaller 6­nozzle Pelton turbine, installed in the powerhouse The gross head of the main station is around 78 metres, and the Francis turbine is capable of processing large volumes of water over extended periods, as is the case when the snow melts or there is

prolonged rainfall. In contrast, the Pelton turbine offers greater flexibility, can adapt to fluctuating water volumes at consistently high efficiency levels, and forms an ideal combination with the larger Francis turbine. Together, the two turbines produce a bottleneck output of around 5.6MW, and are supplemented by a third turbine that doesn’t operate in the powerhouse.

Green electricity from residual/ecological flows

The third turbine is located in the water intake area and is served by two solid dam walls built years ago by the torrent and avalanche control authority. The intake structure for the new power station was built at the Alte Blauseesperre barrier to utilise the drop of around 21 metres – at the precise location where the diversion channel feeds back into the Obersulzbach. The power plant planners wanted to take advantage of this height diffe­

rence for electricity production, but needed to establish which technical solution could be used to achieve this effectively and economically. The solution was the latest DIVE­COAX turbine, which was developed especially for this purpose by the German turbine specialists DIVE­Turbine. Generally speaking, the DIVE­Turbine is a vertical­flow, speed­controlled propeller turbine whose impeller is directly connected to the generator via the turbine shaft, and permanent completely submerged. “The DIVE­Turbine can process water volumes from less than 200l/s up to 2,200l/s, depending on the inflow”, says Thomas Friedrich, Salzburg AG’s Project Manager, explaining the flexibility of the turbine and the choice of this type of turbine. The benefits in favour of DIVE­Turbine technology were its low construction costs and comparatively high annual power output. Another benefit for the operator is that it can remain in operation, even when the water supply is minimal, since low flow volumes – as a result of extremely cold temperatures – can lead to ice buildup when a turbine is switched off.

Uninterrupted underwater operation

The central consideration when designing the residual hydropower plant was to ensure that the pressure pipe with the DIVE­COAX was seamlessly integrated into the surrounding scenery and natural rock near the Alte Blausee barrier. “We couldn’t install a building for the turbine in the riverbed, so it was clear from the outset that the unit would have to be installed in the free­standing pipeline in the flooded area,” says Christian

Winkler, Sales Manager for DIVE Turbinen GmbH & Co. KG. He explains why, technically, the DIVE­Turbine is particularly suited to this mode of operation: “DIVE­Turbine‘s patented machine design is ideally suited to this type of application. It features a compact, combined bearing unit for the turbine and generator, as well as a maintenance­free DIVE­sealing. These features ensure the machine is permanently submersible and resistant to flooding, as well as being runaway­proof.”

The German hydropower specialist provided the turbine­generator unit, the penstock, and the electrical infrastructure, including the innovative inverters for variable­speed operation. Installation work was carried out in September and October of 2024.

Project-specific adaptations required

Customisation of the site solution by DIVE engineers was crucial to successful project implementation. In addition to special

The HAX turbine runner was milled from solid steel.

The turbine-generator unit is fully integrated into the pipework and was pre-assembled at the DIVE factory.

The residual water from the new Sulzau power plant is fed back into the Obersulzbach at the Alte Blauseesperre dam. The drop of around 21 metres is utilised by the new DIVE-COAX Turbine.

Salzburg

pipe routing adaptations, the engineers were also required to develop the hydraulic design in­house at DIVE via 3D CFD methods. As Christian Winkler recalls, “When adapting the machinery to site conditions, we emphasised both optimum efficiency at the nominal point, and the achievement of excellent partload performance. The goal was to maximise overall yearly performance – and we succeeded.”

The DIVE turbine is basically a double­regulated machine unit with a fixed­blade impeller. Double regulation is achieved via the adjustable guide vanes and speed variation options. The hydraulic design provided for a diagonal turbine –optimised for variable­speed operation with fixed impeller blades and an outer ring. DIVE refers to this as a HAX impeller due to the semi­axial flow. The machine itself is a COAX turbine, since the flow through the guide vane is coaxial. This set­up allows the DIVE turbine to be operated effectively across a wide load band – a key quality, as it is a necessity at the Sulzau residual water power plant. The turbine is commonly operated in winter, even when flow volumes are well below 10 per cent of the standard nominal flow rate.

Negligible damage from debris

Another reason the DIVE turbine is ideally suited to the location on this rushing Austrian mountain river is its all­round resis­

tance to abrasion caused by debris. This is due to its geometry, the overall hydraulic design and the materials used. Larger particles in particular cause very little damage to the impeller whose excellent mechanical integrity is essentially due to its having been manufactured from solid steel blank. “After machining, this particular impeller was subjected to a special hardening procedure, necessitated by the fact that the Obersulzbach River also carries large volumes of glacial erosion particles known to increase the risk of abrasion,” explains project manager Felix Frey.

Inverter enables variable speeds

DIVE Turbines also paid close attention to the planning of the project­specific electrical infrastructure, particularly the inverters required for variable­speed power plant operation. Explaining the details, Sven Hermann, Head of Electrical Engineering states: “Obviously, the generation of specific speed set points is important for this type of application. This was implemented while keeping a keen eye on hydraulic and electrical stability. It was essential to avoid any mechanical or electrical resonance during regenerative feedback via sensorless speed control,” Hermann also pointed out that complexity for customers was reduced in favour of control system robustness.

Speed control is facilitated by a permanent magnet generator, driven gear­

TECHNICAL DATA

free by the DIVE Turbine impeller and the electronic converters. Inverter operation of the DIVE turbine enables electricity to be generated from as little as 5% of nominal flow; a key reason for the excellent suitability of this solution on a dynamic alpine river.

Powerful 360-kW power pack

The German hydropower specialists installed a DIVE COAX turbine with a runner diameter of 650mm on the Obersulzbach. The unit is specifically designed for use with residual/ecological flows ranging from 220 l/s to 2.2 m³/s, with a head of 21.05 m. The residual water turbine achieves a maximum expansion capacity of 360kW. As the plant uses a completely enclosed pipe system, and the turbine and generator form a compact gearless unit within, the ensemble operates at very low noise and vibration levels. In total, the residual water hydropower plant alone generates around 1GWh of renewable electricity in a standard year; enough to serve around 400 Austrian households.

The residual water turbine was commissioned successfully in November 2024, and the main power plant was completed on schedule in the spring of this year. Altogether, the main power plant and the new residual power plant will supply Salzburg AG with enough electricity to power 5,000 households.

• Net­Head: 20,55 m . Flow Rate: 2,2 m3/s

Turbine: DIVE­COAX­Turbine

Runner Speed: 100 ­ 650 rpm

• Nominal Output: 360 kW

Axis: vertical

. Runner diameter: 650 mm

. Generator: PMG

• Manufacturer: DIVE Turbinen GmbH & Co. KG

As with all DIVE products, the compact PM generator is pink – and is completely surrounded by drive water in the pipe system.

The German hydropower specialists at DIVE also supplied the piping system for the residual hydropower plant, which was delivered with the turbine-generator unit by truck.

SUCCESSFUL 22ND VIENNAHYDRO: HYDROPOWER AS THE KEY TO THE ENERGY TRANSITION

Austrian moderator Stefan Gehrer (center) moderated an exciting panel discussion on „The role of hydropower in the future energy transition“ with Peter Stettner (European Technology and Innovation Platform, ETIP Hydropower) and Elena Vagnoni (European Energy Research Alliance) as well as the online participants

The 22nd International Seminar on Hydropower Plants, better known as Viennahydro, was held at the Conference Center Laxenburg near Vienna from November 13 to 15, 2024. The renowned event, which has been held every two years for over 40 years, brought together around 200 participants from 20 countries. Experts, scientists and industry representatives discussed innovative technologies and challenges in the field of hydropower, which plays a central role in the future climate-friendly energy supply.

The event was opened at the Conference Center in Laxenburg Castle just outside Vienna by the hosts Prof. Dr.-Ing. Christian Bauer, Dean of the Faculty of Mechanical and Industrial Engineering at TU Wien, and the Rector of TU Wien, Univ. Prof.Dr.-Ing. Jens Schneider, who welcomed the 200 or so visitors together with Environment Minister Leonore Gewessler and at the same time introduced the core topic of the event. The central question of “the role of hydropower in the future energy transition” was then explored in greater depth during a panel discussion, in which prominent representatives from politics, the energy industry and science had their say, specifically Elena Vagnoni from the European Energy Research Alliance (EERA/Joint Program Hydropower), Matteo Bianciotto from the International Hydropower Association (IHA), Thomas Schleker from the European Commission, Dirk Hendricks from the European Renewable Energies Federation (EREF) and Peter Stettner from the European Technology and Innovation Platform (ETIP Hydropower).

The composition of the panel reflected the international focus of the event, but also showed that there was a broad consensus in the discussion about the growing importance of hydropower, despite some differences in perspective.

Internationally oriented

Prof. Dr.-Ing. Christian Bauer has been involved in the traditional hydropower event since 2008. He and his team are the driving forces behind it. For Dean Bauer, the international nature of Viennahydro is an important success factor: „We see Vien-

Traditionally, the Conference Center Laxenburg on the outskirts of Vienna provides a dignified setting for the Viennahydro, which takes place every two years.

nahydro as an ideal platform for an effective exchange on the topic of hydropower. In Austria, the community, i.e. educational institutions such as universities, manufacturers, operators and consultants, is very well networked. This characteristic is also extended to the international arena through the conference.“ Its international orientation is and remains the central feature of Viennahydro, which also focuses on young talent. For doctoral students in particular, the event offers an excellent opportunity to present their research to an expert audience and make valuable contacts.

The quality of Viennahydro is guaranteed by a 40-member expert committee, which only accepts papers with high scientific and technical standards. This ensures that the event is not only convincing in terms of content, but also remains a benchmark for other industry events.

In-depth coverage of topics

This year, Viennahydro once again lived up to its reputation: no other hydropower event of this size goes into such depth and covers such a broad range of topics. This year‘s focus was on the following topics: Innovation, trends and future technologies; Flexibilization and smart grids; Requirements from the power grid to energy generation & storage; Pumps and pump turbines; Digitalization at machine and system level; Planning and operation of speed-controlled pumped storage plants; Operation, maintenance, rehabilitation and modernization; Design norms, standardization & legal aspects; Physical modeling and numerical simulations; Experimental investigations on models and prototypes; Cavitation under extreme load conditions; Hydraulic systems and transient behavior; Market change, business models and economics of hydropower; Sustainability and environmental impact; and Small hydropower. The technical and scientific program included around 50 specialist presentations. In general, the main question across all subject areas was: What research and innovations are needed for the future of hydropower? And it was precisely to this question that the three days of Viennahydro succeeded in finding exciting and informative answers time and again.

Networking in a cozy setting

The event also offered some industry companies an excellent setting to present their products and services to a highly knowledgeable audience. And, of course, the Viennahydro platform

also offered the best opportunities for networking across national and continental borders. A social highlight in 2024 was once again the joint visit to the traditional Fuhrgassl-Huber wine tavern in Neustift in Walde (sponsored by Voith Hydro) on the evening of day 1, as well as a cocktail reception in the elegant ambience of Vienna City Hall on the evening of the second day of the event.

The Viennahydro thus remains not only a platform for the exchange of opinions, but also a pacemaker for the further development of hydropower as a sustainable energy source of the future. The event made it clear that hydropower is not only a proven energy source, but also one with a promising future. The flexibility of storage power plants makes them indispensable for stabilizing modern power grids, which are increasingly burdened by fluctuating renewable energies such as wind and solar energy. Dean Bauer emphasized that hydropower could be the key to using existing infrastructure more efficiently. The successful organization of this year‘s conference has already set the course for the next edition: The 23rd Viennahydro will take place in November 2026. Hydropower enthusiasts from all over the world can look forward to another event that combines innovation, knowledge and networking at the highest level.

Industry specialists such as EFG from Carinthia took the opportunity to present their products to an extremely knowledgeable audience: Rolf Gschwind, Martin Goldberger and Werner Goldberger (from left)

As usual, Viennahydro offered exhibiting industry representatives a professional atmosphere in which to talk to potential customers.

In her speech, former Federal Minister Leonore Gewessler emphasized the essential importance of hydropower for a sustainable and stable energy supply. Dean Christian Bauer moderated the opening of the conference.

REVOLUTIONARY HORIZONTALLY – SETTING NEW STANDARDS WITH THE FIRST HORIZONTAL SIX-NOZZLE PELTON TURBINE

One particular challenge has kept Voith Hydro’s development engineers busy for more than 10 years: What if we could arrange Pelton turbines with three or more nozzles horizontally without sacrificing performance, instead of vertically, as is the norm today? Wouldn’t this make maintenance work and repairs much easier and safer? In addition, it would be possible to replace turbines without major structural works in the event of a plant modernization. Furthermore, new plants would require less excavation work and a smaller footprint. The engineers at Voith Hydro dared to take the plunge – ultimately with success.

The first Pelton turbines were positioned horizontally and equipped with one or two nozzles. If they were built with more nozzles, however, the backsplashing water slowed down the runner and thus reduced the turbine’s efficiency.

In order to be able to use more nozzles and thereby increase output, turbines with vertical shafts were therefore installed from the 1950s onwards. In this arrangement, the water discharged by the buckets can be drained upwards and downwards without much effort.

“We asked ourselves how we could combine the advantages of a horizontal shaft with those of a six­nozzle arrangement,” explains Reiner Mack, a development engineer at Voith Hy­

dro. It quickly became clear to him that the only way to install more nozzles in a horizontal turbine was to improve the water management.

Using existing space more effectively

But how could this challenge be solved horizontally? Mack describes Voith Hydro’s approach like this: “We effectively utilize the available space by using a cone that acts both as a baffle plate for the outflowing water and as a drain for the water that would fall back onto the runner without the cone.” This prevents the runner from being slowed down by water splashing back onto it.

With the first six-nozzle horizontal Pelton turbine, installed in the Gerlos 1 storage power plant in Tyrol, Voith Hydro is setting new standards.

The first six-nozzle horizontal Pelton turbine has been successfully in operation in the Gerlos 1 storage power plant since October 2022.

© Voith Hydro

“We refined the methods in recent years so that we can now also analyze the housing flow or the water flow downstream of the turbine. This progress played a significant role in the successful development of the new concept,” explains Peter Mössinger, responsible for the Pelton turbines’ numerical flow simulation.

The implementation of this concept in the real world was preceded by complex simulations and model tests. “The interaction between the water jet and the buckets of the Pelton wheel is extremely short, often just a few milliseconds,” explains Peter Mössinger, responsible for the Pelton turbines’ numerical flow simulation. This is why numerical forecasting of the bucket flow is extremely complex and requires a great deal of effort. “In addition, we refined the methods in recent years so that we can now also analyze the housing flow or the water flow downstream of the turbine. This progress played a significant role in the successful development of the new concept.”

But the model testing technology also faced new challenges. “The greatest difficulty our model machine designers faced was certainly ensuring that we had the flexibility to make advancements to the housing,” explains Mössinger. “Not all numerically developed versions prove themselves right away, which means that flexibility in the model machine is extremely important.”

Everything at the same height makes maintenance easier Ultimately, the many years of research paid off, and the new concept has been able to meet expectations. Voith Hydro calls the innovation HP3+, which stands for horizontal Pelton turbines with three or more nozzles. Increasing the number of nozzles increases the power density and thus also the rotational speed. As a result, both the generator and turbine can be built smaller. Mack sees another major advantage: “Servicing a horizontal machine is much easier than a vertical shaft because everything is on one level in a horizontal arrangement.” The maintenance team can stay on one floor and in the powerhouse environment when servicing the turbine and has a direct view of the overhead crane. When installing vertical arrangements, the installation team often has to work across several floors under

makeshift lighting conditions using chain hoists. Accordingly, this requires much more effort to create a safe working environment. “Our colleagues from St. Pölten came up with a lot of ideas during the mechanical design work for the HP3+ in order to be able to service the turbine quickly and safely,” says Mössinger. “The result has likewise been innovative solutions that didn’t exist before.”

In addition, about 20 years ago, companies started to completely gut old powerhouses that were equipped with horizontal machines in order to then use vertical machines. This required dismantling the underwater channels and the entire infrastructure on site. Because the powerhouse is too low to properly perform maintenance on a vertical machine, however, this solution always remained a compromise. “When performing general maintenance, it is often necessary to tilt the entire generator and then dismantle the rotor in a horizontal position. This obviously involves a considerable amount of work,” explains Mack. When utilizing horizontal units, this effort is, of course, no longer required. Construction measures are also much more modest, as the new horizontal machines can, ideally, be placed on top of the existing foundations.

The Gerlos storage power plant: Overview longitudinal section

The new turbine was presented to the public for the first time at a leading international hydropower conference in Vienna. The concept generated a great deal of interest there from hydropower operators. The exciting question was then how the new turbine would prove itself in practice. The corresponding pilot project was already underway. This was because Voith Hydro had already found a suitable company that had the necessary pioneering spirit, courage and technical understanding required for the new solution.

Pilot project at the Gerlos 1 storage power plant in Tyrol

The candidate that met these requirements is none other than Austria’s leading energy transition company Verbund. It operates the Gerlos 1 storage power plant in the Zillertal valley in Tyrol. This plant was brought into operation in 1949 and now has an annual capacity of 326 GWh. As a result, the power plant supplies over 70,000 four­person households with renewable energy, as the first six­nozzle horizontal Pelton turbine has been successfully in operation here since October 2022. It replaced the four two­nozzle vertical machines previously installed. This solution reduces the number of units requiring maintenance, not only in terms of turbines, but also generators and power lines. This results in significant financial savings. In addition, the horizontal solution makes maintenance significantly easier and safer.

Perfect for modernization projects

The pilot project also clearly shows why the horizontal arrangement of the Pelton turbines particularly benefits modernization projects: “At the Gerlos 1 plant, four very old vertical turbines were replaced with one horizontal unit because the powerhouse ceiling was too low and the powerhouse area was too small for a vertical one,” Mack explains.

The specification originally envisaged a conventional twin unit with one generator and two two­nozzle turbines each. There simply wasn’t enough installation space for this solution, however. “For our HP3+ solution, we were able to gain valuable space by developing the inlet numerically,” Mössinger adds.

“This ensured that the unit would be well positioned in the powerhouse for all maintenance operations.”

These advantages are also proving their merits in a second pilot project at the Vermuntwerk plant in Vorarlberg, which is operated by Illwerke. Here, five two­nozzle units are being replaced by two turbines with six nozzles – while total plant capacity will remain the same. “Two turbines means you only have to maintain two runners and two generators and also only two transformers, instead of five like before. This will significantly reduce maintenance costs.”

Mack has been involved in the development of this innovative solution from the very beginning. “It was great seeing the first prototype of an HP3+ installed and then in operation.” To him, one thing is abundantly clear: “On the one hand, developing a solution like this requires members of management at Voith who have the necessary vision to see that such an idea will be successful. On the other hand, confidence in our solution on the part of customers, which has grown over many years of continuous collaboration, is also necessary. At the end of the day, we want our customers to be satisfied with our turbines, that’s the main thing.”

Innovative turbine developers at Voith: Reiner Mack, Dr. Peter Mössinger and Dr. Jörg Necker (from left)

The two power houses Gerlos 1 (right) and Gerlos 2 in the Zillertal Valley. The plants supply more than 70,000 households with renewable energy.

© Voith Hydro

© Voith Hydro

Built on Experience and Expertise Voith HyService

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With a global network of experts, including specialists based in Austria, we are committed to enhancing the performance of your plant. Let’s take the next step together – for a more powerful and profitable use of hydropower. Choose a partnership that goes beyond maintenance – choose HyService for sustainable success.

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