ARC f386M + ARC f388R Professor Vincent Snyder University of Texas at Austin 07. 06. 2012
AN ALTERNATIVE AND RENEWABLE ENERGY SOURCE IN GERMANY
BIOMASS CONNER BRYAN
BIOMASS AN ALTERNATIVE AND RENEWABLE ENERGY SOURCE IN GERMANY Conner Bryan ARC f386M + ARC f388R Professor Vincent Snyder University of Texas at Austin 07.06.2012
i
CONTENTS
INTRODUCTION
1
RENEWABLE ENERGY USE IN GERMANY
3
REGULATION OF PRODUCTION AND USE OF BIOMASS
6
BIOMASS POTENTIAL
7
TYPES OF BIOMASS
8
ANAEROBIC DIGESTION
14
CONVERSION PROCESS
19
BIOMASS-POWERED COGENERATION
20
GUT KARLSHOF; ISMANING
21
VAUBAN NEIGHBORHOOD; FREIBURG
23
24
ETHICAL AND HEALTH EFFECTS OF BIOMASS
CONCLUSION
25
ii
INTRODUCTION
Against a backdrop of today’s rapidly globalizing world full of warfare, political unrest, increasing natural disasters and general uncertainty of what the future may hold, one thing is certain: we have a dwindling energy source in non-renewable fossil fuels and advancing climate change which must be addressed for the survival of humanity. The global energy system will continue to grow significantly in the years to come especially due to the strongly increasing energy demand of the emerging economies of India, China, Brazil, and sub-Saharan Africa.1 A large majority of this new demand will be met with non-renewable energy sources like coal-fired power plants, which use large quantities of water and release large amounts of carbon dioxide and harmful pollution into the air, causing large-scale environmental damage. This is mainly due to the fact that coal is relatively cheap, easily accessible and uses existing conversion technologies and plant facilities. We face an urgent task of making our energy supply more efficient and environmentally sound in the wake of all of this. In recent years there has been an increase of new and innovative alternative strategies in the global energy system. Biomass, or bioenergy, offers a renewable energy source that we can use to help curb our addiction to fossil fuel use. When used as a source of energy, biomass has three Kaltschmitt, Martin, “Biomass for Energy in Germany: Status, Perspectives and Lessons Learned,” 1
Journal of Sustainable Energy & Environmental Special Issue (2011) 1.
major advantages: it spares fossil fuel reserves, helps mitigate the effects of climate change, and fosters innovation, value creation and employment.2
“National Biomass Plan for Germany”, accessed July 1, http://www.bmelv.de/cae/servlet/ contentblob/750066/publicationFile/41337/ BiomassActionPlan.pdf 2-5
Germany stands as a global leader in research, development and implementation of biomass technologies today. As of 2011, biomass meets approximately seven percent of Germany’s primary energy demand3 and according to the The National Biomass Action
Plan for Germany, issued in April 2009, it is estimated that it may be possible to double
1
the share of bioenergy in Germany’s energy supply by 2020.4 The increase in biomass use in recent years can be directly correlated to the implementation of progressive governmental policies; the European Union and the German government have issued several acts to promote and support the use of renewable energy for the provision of heat, electricity and transportation fuels.5
However, it is important to note that biomass is not the panacea to our energy situation. We must understand the possible negative side effects of the use of this energy resource in order to usher truly sustainable growth in the global energy sector. Biomass is not available in unlimited quantities; hence, the promotion of its use must ultimately be seen in the context of promoting the use of all other renewable energy sources in combination with greater efforts toward reducing energy consumption and improving overall energy efficiency. From a social sustainability standpoint, we must also ensure that the growth of biomass use does not compromise the situation in other countries, especially in developing nations facing critical food shortfalls. The rise of biomass demand in Germany and other industrialized countries throughout the world may lead to a increase in global biomass material prices, which could have a detremental effect on developing nations. Also, there are recent studies which have found that emissions from biomass energy generation may contribute to harmful health effects due to increased quantities of toxic airborne particulate matter.
The goal of this paper is to assess the status of the use of biomass-based energy within Germany, while drawing attention to new techniques and technologies that are being introduced within this growing energy sector. Various conversion processes will be discuessed in order to explain how biomass is used as a fuel source. Two case study
2
sites will be presented as examples of current comprehensive biomass systems in Germany: the Gut Karlshof cattle farm within the Fischerhäuser district of Ismaning and the Vauban district of Freiburg. Finally, some negative side effects of biomass energy will be explored.
RENEWABLE ENERGY USE IN GERMANY
At present, the total energy consumption in Germany consists of 89 percent fossil fuels (hard coal, lignite, mineral oil, natural gas) and nuclear energy, and 10.1 percent renewable energy sources (biomass- 7.0, wind energy- 1.6, hydropower- 0.8, other renewables like solar and geothermal power- 0.7 percent).6
Renewable energy supply increased from 236 billion kWh in 2008 to 238 billion kWh in 2009 (Fig. 1), according to data provided by the Federal Ministry for Environment, Nature Conservation and Nuclear Safety (BMU) and the Arbeitsgruppe Erneuerbare Energien (AGEE Stat). In total, 109 million tons of greenhouse gas emissions and 107 million tons of CO2 equivalents were avoided in 2009, saving the government 7.9 billion Euros in spared environmental and health damages. Simultaneous to this, fossil fuel Kaltschmitt, Martin, “Biomass for Energy in Germany: Status, Perspectives and Lessons Learned,” 6
Journal of Sustainable Energy & Environmental Special Issue (2011) 5.
imports amounting to 6.4 billion Euros were avoided and the domestic value creation was consolidated.
There was a considerable increase of renewable energy supply in gross energy consumption in the heat sector: 7.4 percent in 2008, up to 8.4 percent in 2009corresponding to an increase in heat production by 110 billion kWh. Of this supply, biomass accounted for 91 percent, due primarily to an increased use of wood for heat
3
ELECTRICITY Hydropower
19.0
Wind energy
37.8
Biomass (total)
28.6
Solid biomass, including biogenic waste
*Numbers are listed as total TWh: 1 TWh = 1 billion kWh
17.1
Biogas 10.0 Liquid biomass 1.5 Landfill and sewage gas
2.0
Photovoltaics
6.2
Geothermal energy
0.019
Total electricity
93.5
HEAT Biomass (total) Solid biomass, including biogenic waste
100.8
82.9
Liquid biomass 7.7 Biogenic gaseous fuel 10.2 Solar thermal energy
4.8
Deep geothermal energy
0.3
Near surface geothermal energy
4.7
Total heat
110.5
Sybille Tempel, Study on Biomass Trade in Germany (Berlin: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, 2010), 6.
7
BIOGENIC FUELS Biodiesel (approx. 2.5 mill. t)
26.0
Vegetable oil (approx. 0.1 mill. t)
1.0
Bioethanol (approx. 0.9 mill. t)
6.7
Biogenic fuels (total)
33.8
Total final energy from renewable energy sources
237.8
Fig. 1: Contribution of renewable energy sources to energy supply in Germany 20097
4
production. The share of renewable energy supply in gross final electricity consumption also grew: from 15.2 percent in 2008 to 16.1 percent in 2009, totaling an installed capacity of all renewables around 5400 MW.8
Employment increased from 278,000 people working in the renewable energy sector in 2008 to 300,5000 people in 2009.8 Biomass makes the greatest contribution to gross employment with 36 percent (109,000 jobs) followed by wind with 29 percent, solar power with 27 percent and geothermal and hydro with 3 percent each.9 These figures show clearly that renewable energy is becoming an important economic factor in Germany.
Total: 237.8 TWh Biogenic solid fuels, heat 42.4%
Biofuels 14.2%
Geothermal energy 2.1%
Solar thermal energy 2.0%
Hydropower 8.0%
Photovoltaics 2.6%
Biogenic fuels, electricity 12.8%
Wind energy 15.9% Biomass (total)*, including biofuels: 69%
* Solid, liquid, gaseous biomass, biogenic share of waste, landfill and sewage gas Source: BMU-KI III according to Working Group on Renewable Energies- Statistics (AGEE-Stat); all figures provisional
Fig. 2: Structure of final energy supply from renewable energy supply in Germany 2009 as percentages
5
REGULATION OF PRODUCTION AND USE OF BIOMASS
On March 9, 2007, the European Council convened to set realistic goals and targets relating to renewable energy use. A binding EU-wide target of 20 percent renewablesgenerated electricity was set for 2020. Further 2020 targets are to reduce the overall energy demand by 20 percent and to increase the share of renewable energy in fuel supply to 10 percent. The European Council expressly stated that the 10 percent target is only binding if the energy production is sustainable and second generation biofuels are available commercially. Announced on January 23, 2008, the EU Climate and Energy Package designed for use in implementing these goals has since been adopted.10
There have been a number of key pieces of legislation from both the EU and the German goverment. The following list is a synopsis of these.
European Union legislation Directive 2009/28/EC on the promotion of the use of energy from renewable sources Directive 2009/30/EC on environmental quality fuel standards (Fuel Quality Directive) Directive 2006/32/EC on energy and end-use efficiency and energy services
Sybille Tempel, Study on Biomass Trade in Germany (Berlin: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, 2010). 8-10
German national legislation Renewable Energy Sources Act (Erneuerbare Energien Gesetz – EEG), last amendment January 2009 Renewable Energy Heat Act (Erneuerbare Wärme Gesetz – EEWärmeG) January 2009 Energy Taxation Act (Energiesteuergesetz - EnergieStG), last amendment 2009
6
Gas Grid Access Ordinance (Gasnetz Zugangs Verordnung – GasNZV) and Gas Grid Payment Ordinance for feed-in of biomethane into the natural gas grid Biofuels Quota Act (Biokraftstoffquotengesetz (BioKraftQuG) Ordinance on Sustainable Electricity Generation from Liquid Biomass (Nachhaltigkeitsverordnung Biomassestrom – BioSt-NachV) Biofuel Sustainability Ordinance (Biokraftstoff-Nachhaltigkeitsverordnung – BiokraftNachV) Federal Immission Control Act (Bundesimmissionsschutzgesetz - BImSchG), last amendment 2010 Market Incentive Programme (MAP) under the Renewable Energy Heat Act for support of RES in buildings.
BIOMASS POTENTIAL
In Germany, the available biomass potential from forests is increasing. The last Federal Forestry Inventory conducted in 2002 has identified wood reserves of 3.4 billion m3, currently the largest amount in Europe.11 Nevertheless, not the whole increment of growth can be deployed for industrial or energy use. A certain amount of wood residues have to be left because the nutrient balance has to be maintained according to sustainable forestry management.
In agriculture, 1.75 million hectares of arable land was used to grow energy crops in 2008.12 In the years to come, high yield levels and further increasing harvests are expected. Since population is decreasing slightly, experts predict a good potential of resources will continue to be available for use in this industry.
7
TYPES OF BIOMASS
Biomass can be split into two categories: waste biomass and energy crops.
WASTE BIOMASS
Forestry residue Wood is the most commonly used biomass fuel for heat and power, and unwanted wood waste is a by-product of many forestry operations. Forestry residues include biomass that is not harvested or removed from logging sites in commercial forests, as well as material resulting from forest management operations such as pre-commercial thinnings and removal of dead or dying trees. Forest thinning is necessary to help some forests regain their natural health, but for smaller woodlands the cost of removing the wood cannot be recovered through timber sales due to their poor quality. Using these materials for electricity generation recovers their energy value while avoiding landfill disposal.
Substantial areas of forest are needed to support a wood-fired power station. For example, a 6MW station with an efficiency of 20% would need between 430 and 2,150
Sybille Tempel, Study on Biomass Trade in Germany (Berlin: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, 2010). 11-13
hectares of sustainably managed forest at harvest per year.13 This exceptionally wide range shows the variable yield of forest residues. The yield itself depends on various factors such as terrain, accessibility, tree species and age, and end use of the timber as opposed to the residues. However, the feasibility of this will also depend on other issues, such as the conservation status of the woodland, accessibility and countryside policies.
8
Animal Farming There are two types of animal farming biomass sources: farm slurries and poultry litter.
Farm slurry is a watery animal sewage containing a high concentration of suspended solids. Farm slurries are obtained mainly from pig farming and cattle farming. It can be used as a fuel source for anaerobic digestion.
Poultry litter is the bedding material collected from broiler sheds. It’s usually made up of wood shavings, shredded paper or straw, mixed with the chicken droppings. It has a calorific value of 9-15GJ/tonne, which is slightly lower than that for wood. It has a moisture content of between 20-50% depending on the methods of husbandry used by farmers.14
The practice of spreading large quantities of poultry litter on the land is no longer considered acceptable because it can cause serious environmental problems by polluting watercourses and producing odours if not correctly managed. The poultry farming industry has come under increasing pressure from environmental agencies to “Biomass Basics,” accessed June 29, http://www. esru.strath.ac.uk/EandE/Web_sites/03-04/biomass/ background%20info4.html. 14
adopt a more environmentally acceptable method of disposal.
Cattle Farming Cattle farming techniques significantly affect the quantity and quality of manure that may be delivered to the anaerobic digestion system. The number of cows, the housing,
9
15
16
“Swabhiman” accessed July 1, 2012, http:// swabhimancapital.com/ 15
“Cow Power” accessed July 1, 2012, http://www. wickedreport.com/images/CowPower_02.jpg 16
10
transport, and bedding systems used by the farms determines the amount of slurry that must be used and therefore the amount of energy produced.
Cattle farming may be housed using a variety of methods. The most commonly used systems include free stalls, corrals with paved feed lanes, and open lot systems. The type of housing used determines the quantity and quality of manure that can be economically collected.
In free stall barns the manure can be flushed, scraped, or vacuum collected and loaded.
Pig Farming Several options for collecting and storing swine manure are available, depending on the manure form. Common storage methods include under floor pits, outdoor (above or below ground) structures, earthen pits, lagoons and holding ponds. Flushing gutters and scraper systems are among the methods used to collect and transport manure to appropriate storage facilities.
As with cattle farming, the manure can be used as a fuel source for anaerobic digestion.
Slaughterhouse & Fishery Waste At a slaughterhouse or a fish processing plant, there is a huge amount of organic waste. This has the possibility of being a danger to the environment and human or animal health. The EU Animal By-Products Regulation (2003) specifies these animal wastes may be disposed of safely. This can be an extremely costly process, but this type of waste can also be used as a feed stream for anaerobic digestion.
11
Organic Municipal Solid Waste (MSW) Organic MSW is any matter collected from commercial or residential properties such as food waste, paper etc. Organic waste, whether from commercial or residential properties, makes up a substantial amount of waste that is deposited in landfills. As with other wastes, it can be converted into energy by various methods. One is direct combustion (incinerator), or by anaerobic digestion in a landfill or in a process plant.
New regulations require landfills to collect methane gas for safety and environmental reasons. Methane gas is colorless and odorless, but it is not harmless. The gas can cause fires or explosions if it seeps into nearby homes and is ignited. Landfills can collect the methane gas, purify it, and use it as fuel.
Methane, the main ingredient in natural gas, is a good energy source. Most gas furnaces and stoves use methane supplied by utility companies.
Today, a small portion of landfill gas is used to provide energy. Most is burned off at the landfill. With today’s low natural gas prices, this higher-priced biogas is rarely economical to collect. Methane, however, is a more powerful greenhouse gas than carbon dioxide. It is better to burn landfill methane and change it into carbon dioxide than release it into the atmosphere.
Sewage Waste Sewage waste is a source of biomass that is comparable to the other animal wastes previously mentioned. Energy can be extracted from sewage using anaerobic digestion, pyrolysis, or drying and incineration.
12
17
18
“Food Waste Collection” accessed July 1, 2012, http://www.liquidenviro.com/Services/ OrganicWasteCollection.aspx 17
“Flickr” accessed July 1, 2012, http://1.bp.blogspot. com/-uJtt9RoewfI/TZcp1UDT54I/AAAAAAAAACI/ wR0sk9lcoto/s1600/landfill13.JPG 18
13
Anaerobic Digestion Biogas digesters are airtight containers or pits lined with steel or bricks. Waste put into the containers is fermented without oxygen to produce a methane-rich gas. This gas can be used to produce electricity, or for cooking and lighting. It is a safe and clean- burning gas, producing little carbon monoxide and no smoke.
Biogas digesters are inexpensive to build and maintain. They can be built as familysized or community-sized units. They need moderate temperatures and moisture for the fermentation process to occur. For developing countries, biogas digesters may be one of the best answers to many of their energy needs. They can help reverse the rampant deforestation caused by wood-burning, and can reduce air pollution, fertilize over-used fields, and produce clean, safe energy for rural communities.
COVER (FLEXIBLE OR RIGID)
BIOGAS STORAGE INFLUENT MIXER “EPA, Anaerobic Digestors� accessed July 1, 2012, http://www.epa.gov/agstar/anaerobic/ad101/ anaerobic-digesters.html 19
MIXER
EFFLUENT
HEAT EXCHANGER MANURE RECEPTION PIT WITH PUMP
CONCRETE PAD
Figure 3: Typical complete anaerobic digestor with mixing.19
14
ENERGY CROPS
Energy crops are produced specifically for their fuel value. An energy crop is a plant grown as a inexpensive and low-maintenance harvest used to make biofuels, or combusted to generate heat or electricity for its energy content. Energy crops are categorized as herbaceous or woody plants; many of the latter are grasses.
Commercial energy crops are typically densely planted, high-yielding crop species where the energy crops will be combusted to generate power. Woody crops such as willow or poplar are widely utilized, as well as temperate grasses such as Miscanthus and Pennisetum purpureum (both known as elephant grass). If carbohydrate content is desired for the production of biogas, whole-crops such as maize, Sudan grass, millet, white sweet clover and many others can be made into silage and then converted into biogas.
Through genetic modification and application of biotechnology, plants can be manipulated to create greater yields, reduce associated costs, and require less water. In many cases, increased levels of fertilizers can be used to boost yields, however this can lead to greater environmental damage over the course of production.
TYPES OF ENERGY CROPS
Miscanthus Miscanthus crops are woody, perennial, rhizomatous grasses, which can be harvested annually for at least 15 years. By the third year harvestable yields are between 10-13
15
20
21
“CALS Bioenergy Feedstock Project” accessed July 1, 2012, http://nybioenergy.org/generalInformation/ biomass/Pages/default.aspx 20
“Diesel Power” accessed July 1, 2012, http://www. dieselpowermag.com/tech/general/0809dp_how_to_ make_biodiesel_from_algae/photo_01.html 21
16
tons per hectare. Peak harvestable yields of 20 tons per hectare have been recorded. 22,000 tons can provide enough electricity to power 2,000 homes.22
Wood Pellets Pellets are a refined, solid fuel biomass with a low moisture content, which makes it easy to transport, store and convert into energy. It is manufactured from saw dust, wood chips, shaving or bark. Pellets are typically 6-8mm in diameter and 5-30 mm long.
Biomass is usually processed to pellets in plants using piston or roller presses. The raw material used may be sawdust, shavings or chips. The raw material is heated, to make the fuel dry and at the same time transforming the lignin acting like the glue that holds the raw material together, which makes it possible to shape the pellets in the desired form.
The following list contains the main advantages of using pellets:
“Biomass Types� accessed June 29, 2012, http:// www.esru.strath.ac.uk/EandE/Web_sites/03-04/ biomass/background%20info4.html 22
Pellets brun almost without any smoke development, the dust in the flue gas is very basic. The ash produced is very basic with barely any toxins. Less carcinogens are produced in the high temperature combustion of pellets compared with unrefined fuel. Pellets have a very low metal content. Only small quanitites of NOX oxides are formed.
To use pellets for heating, a specialised pellets burner is needed. The ash left over from the burning is rich in minerals, and can be used as a soil conditioner. 17
Woodchips The term ‘woodchips’ refers to mechanically-processed wood particles, ranging in size from 1 to 100 mm. The price of woodchips largely depends on their water content, as high water content reduces the energy content. Moisture is therefore just as important as chip size in determining the price of woodchips.
The criteria used for woodchip quality are as follows:
Chip size: only the “fine” (smaller than 30 mm) and “medium” grades (below 50 mm) are suitable for small-scale installations Water content: this determines the energy content of the fuel on the one hand and its storability on the other Bulk density: this indicates the weight per cubic meter (bulk volume) and depends on wood type, particle shape, degree of compaction and water content.
OTHER BIOMASS FUELS
In addition to the above fuels, the following other plant products are also classed as biomass:
algae straw wheat potatoes sugar beet
18
CONVERSION PROCESS
Biomass is converted into useful energy (electricity and heat) in a multistage supply chain beginning with its collection. The biomass then goes through a series of mechanical processes including storage and transporation.
There are three options of conversion that each of the biomass fuel types undergo to be transmformed into heat or eletricity: thermo-chemical, physico-chemical, and biochemical.
To limit the scope of this paper, the conversion processes will not be discussed in detail.
Kaltschmitt, Martin, “Biomass for Energy in Germany: Status, Perspectives and Lessons Learned,� 23
Journal of Sustainable Energy & Environmental Special Issue (2011) 2.
Figure 3: Possibilities to provide heat and/or power from biomass.23
19
BIOMASS-POWERED COGENERATION:
Cogeneration, or combined heat and power (CHP), is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat in one single, highly efficient process.
CHP generates electricity while also capturing usable heat that is produced in this process. This contrasts with conventional ways of generating electricity where vast amounts of heat is simply wasted. In today’s coal and gas fired power stations, up to two thirds of the overall energy consumed is lost in this way, often seen as a cloud of steam rising from cooling towers.
Their relative sophistication means that the overall efficiency of CHP plants can reach in excess of 90% at the point of use. Coal-fired plant fare less well with an efficiency of around 38%.
As an energy generation process, CHP is fuel neutral. This means that a CHP process can be applied to both renewable and fossil fuels. The specific technologies employed, and the efficiencies they achieve will vary, but in every situation CHP offers the capability to make more efficient and effective use of valuable primary energy resources.
20
CASE STUDY: GUT KARLSHOF; ISMANING
Gut Kalrshof is a farm located in Ismaning- a suburb of Munich which is located just to the north-east of the city. The property is approximately 250 acres in size. Cattle are raised on the property. In addition, crops are grown on the property- potatoes, grains, legumes, silage maize, and other seasonal vegetables.
In 1999, a biogas plant was put into operation at Gut Karlshof. It was extended in 2009 from 140 kilowatts to 420 kilowatts of electrical power (two 210 KW cogeneration systems) and will be expanded in 2012 to 530 kilowatts.
In the plant, organic matter (manure, liquid manure, corn, grass) is converted under anaerobic conditions by bacteria into biogas. This gas mixture consists of 55 percent methane (natural gas component) and is burned in a cogeneration process, and electricity and heat is generated. The heat is used to heat the manor house and the electricity is fed into the grid. It annually produces about 3.4 million kilowatt hours and saves approximately 1,700 tons of CO2.24
“Das offizielle Stadtportal,� accessed July 1, 2012, http://www.muenchen.de/rathaus/Stadtverwaltung/ Kommunalreferat/stadtgueter/gutsbetriebe/karlshof. html 24
The estate has approximately 550 beef cattle and a small flock of sheep fed on the mash from the distillery. The marketing of the cattle meat from the farm is, among other things, used at the Ochsenbraterei at the Oktoberfest in Munich and the butcher alteingessene Vinzenz Murr. The animals are slaughtered at the Munich slaughterhouse. Due to animal welfare concerns, the stables were expanded to include bed bays and run farms in 2000.
21
25
1
26
27
“Das offizielle Stadtportal,� accessed July 1, 2012, http://www.muenchen.de/rathaus/Stadtverwaltung/ Kommunalreferat/stadtgueter/gutsbetriebe/karlshof. html 26-27
22
CASE STUDY: VAUBAN DISTRICT; FREIBURG
The Freiburg suburb of Vauban has undergone massive changes in recent years. The area, which covers 0.4 km², was used as barracks by the French army up until 1992. Now it is a residential suburb with living space for some 5000 citizens, most of whom live in low-energy, ‘passive’ houses. Many of the houses use photovoltaic systems to generate electricity, thus helping to protect the climate. Heat is also provided in an ecologically sound way, thanks largely to a local heating grid which is largely fueled by biofuels and woodchips.
GAS POWERED COGENERATION
A bio-mass fired, neighborhood scale CHP is connected to the district’s heating system. The plant consumes wood chips and serves domestic and hot water heating needs for about 2,000 households. In addition, this plant, together with solar PV panels installed throughout the neighborhood, provides 25% of the electricity for the area.
“Cogeneration,” accessed July 4, 2012, http://www. cospp.com/articles/print/volume-12/issue-5/projectfiles/cogeneration-plant-in-freiburg-achievesefficiency-of-96.html 28
Its sophisticated multiple heat recovery outperforms conventional cogeneration plants. Two exhaust heat exchangers cool the engine exhaust gases in two stages from around 500°C to 650°C and in so doing, they heat the water first to 67°C and then to 90°C.28 In addition, the heat given off by the generator and the engine is not simply allowed to escape into the atmosphere but captured and reused by a heat pump. So the generator room is cooled and the heat supplied to the district heating system at the same time.
23
24
ETHICAL AND HEALTH EFFECTS OF BIOMASS
According to Professor Robert Kunde, at the Bavarian Centre for Applied Energy Research (ZAE), there are over 5 million small-scale residential biomass heating units in Germany. New studies have shown that biomass incineration from these units can cause negative health effects on building occupants, especially in homes with poor ventilation. There are technologies that can be used to filter the exhaust of these units, preventing the particulate matter from escaping into the homes. However, there are currently no regulations in place to ensure that the manufacturers are using these technologies in their units. Greater oversight must be used to prevent avoidable health conditions in residences, as well as larger scale biomass plants.
Intensified biomass use will foster competition for land and for certain raw materials. We must ensure that this growing sector does not drive developing nations with food scarcities to replace food crops with biomass crops. Also, efforts must be made to prevent deforestation in developing nations in order to supply the world with wood to be used as biomass fuel.
“Deforestation,� accessed July 4, 2012, http://www. photovault.com/show.php?cat=Technology/Outside/ Deforestation&tg=TODDVolume01/TODD01_021 28
29
24
CONCLUSION
Biomass is the most important renewable source used by humans to date. Within the global energy system, biomass contributes approximately 10% to the given energy demand and in Germany the share is roughly 7%.30 Based upon many projections, that percentage will significantly increase and biomass will play an ever-increasingly important role in the future. By reducing green house gas emissions, reducing our dependance of fossil fuels, and creating innovation and employment, biomass will help us create a more secure, safe, and clean energy system of the future.
To achieve public acceptance of a wider use of biomass within the global energy system, biomass must be used in a sustainable manner. It must be used in combination with all other renewable energy sources and greater efforts must be taken toward reducing energy consumption and improving overall energy efficiency. Special care must also be taken to ensure that developing nations have a just stake in this growing energy sector.
Overall, Germany has shown that a strategy employing biomass in large quanitities within their overall system is possible and successful. Research, development, and demonstration are vital in promoting biomass use. Ultimately, the continued growth of the biomass energy sector is up to the various government entities around the
Kaltschmitt, Martin, “Biomass for Energy in Germany: Status, Perspectives and Lessons Learned,� 30
Journal of Sustainable Energy & Environmental Special Issue (2011) 9.
world to enact laws, regulations, and incentives. Hopefully, America and other major industrialized countries will use Germany as an example and transition their energy sector toward a more sustainable future.
25