factsheet_biogas_6.pdf

8/10/2019 Factsheet_Biogas_6.pdf

1/7

1

SUMMARYBiogas is a gas produced by anaerobic fermentation of different forms of organic matter and is composed mainly ofmethane (CH4) and carbon dioxide (CO2). Typical feedstocks for biogas production are manure and sewage, residues ofcrop production (i.e., straw), the organic fraction of the waste from households and industry, as well as energy cropsincluding maize and grass silage.

Biogas is supplied to a variety of uses or markets, including electricity, heat and transportation fuels. In many countriesusing the gas for direct combustion in household stoves and gas lamps is increasingly common, producing electricityfrom biogas is still relatively rare in most developing countries. In industrialized countries, power generation is the mainpurpose of most biogas plants; conversion of biogas to electricity has become a standard technology. To improve overallefficiency of biogas utilization, combined heat and power plants are often used, with part of the heat utilized for main-taining reactor temperature and sometimes for heat treatment of the incoming material.

A biogas plant on a farm, for example, has a number of different elements, such as the liquid manure store, the receivingand mixing area, the digester or reactor, the gas storage tank and storage for digester residue. In the case of a combinedheat and power (CHP) application, there also needs to be grid connection for the electricity and a connection to the heatuser. The cost of investment per kW installed electric capacity is about 5 000 Euro for an installation of about 150 kW insize; the specific investment cost/kW or MW capacity is higher for smaller plants and lower for bigger plants.

The global potential of biogas is large enough to provide a substantial share of future gas demand; estimations show that

biogas could cover around 6% of the global primary energy supply, or one quarter of the present consumption of naturalgas (fossil methane gas).

Each country should develop and implement an integrated biogas concept in order to promote the increased productionof biogas. The big advantages of such a strategy would include better progress in mitigating climate change by reducingnational GHG emissions, improving national energy security, and creating new employment in rural regions. Internationalorganizations should support these national efforts.

BIOGAS AN IMPORTANTRENEWABLE ENERGY SOURCE

W B A f a c

t s h e e

t

INTRODUCTIONEnhanced energy security and climatechange mitigation are the main driversfor the transformation of the energysystem from fossil to renewable sources.Biomass has to play a key role in thistransformation to a low carbon economy.

Worldwide, biomass (including putres-cible waste and bio-wastes) accounts formore than two thirds of all renewableenergy supplies. Among biomass sour-ces, biogas is an interesting option witha large potential, offering many excitingpossibilities to supplant and therefore re-duce our dependence on fossil fuels. [1]

Currently the modern biogas productionindustry is just at the beginning of widerimplementation. With the exception ofa few countries, like Germany (which are

First edition May 2013

P h o t o: B e r n d Wi t t e l s b a c h

Biogas energy plant in Germany. Biogas already provides more than 3% of the whole of Germanyselectricity consumption, as well as signicant amounts of industrial heat, transport fuels, and volumeinjected into the natural gas grid.


2/7

2

already demonstrating its real potential)only a tiny part of this global potentialhas been realized. Reasons for the slowdeployment of biogas include: a lack ofinformation about the possibilities of bi-ogas, a lack of a trained labor force, highcapital cost for the setting up of commer-

cial plants, generally inadequate and un-reliable government support policies andthe competition of natural gas as a cheaperalternative in many parts of the world.

From an economic viewpoint nationalbiogas development is effectively stimulat-ed when a signicant cost is put on dispos-al of putrescible wastes or of free emissionsof greenhouse gases arising from this, andalso when nancial stimulus of biogasproduction roughly matches the previouslevels of stimulus of natural gas sourcingor reticulation. Tis latter case may be viaa carbon tax on fossil fuels, transferred toprovide a cost share for biogas productionand processing facilities.

A specic advantage of biogas technol-ogy is in the utilisation of organic wastesand other organic byproducts for energyproduction, as opposed to disposal vialandlls, which inevitably leads to furtheremissions of greenhouse gases by the pro-cess of slow decomposition.

Te purpose of this WBA fact sheet is tooffer to the reader basic information aboutbiogas as renewable energy source theprocess, the feedstock, the versatility of

biogas, the worldwide potential, the cur-rent global signicance and the necessarypolicy measures for further development.

BASICSTe term biogas is used for a gas pro-duced by anaerobic fermentation of dif-ferent forms of organic matter. Biogas isalso produced under anaerobic conditionsin nature, for example in swamps. Tis an-aerobic process is driven by different varie-ties of bacteria, in anaerobic digestor tanks

this is usually at a temperature of C. During this biological process a majorportion of the carbon compounds are con-verted to CH , CO and water. Biogas con-sists mainly of methane, carbon dioxide,and some other minor components. Te

fermentation process also produces a resi-due or sludge that can be used as fertilizer,or after drying as feedstock for combus-tion in district heating or CHP plants.

Te process itself occurs in airtight bi-ogas digesters without oxygen. Te rate ofthe process depends on the feedstock andseveral other parameters. Te digestiontime varies from several hours (for sugars,and alcohol) to several weeks (in case ofhemicelluloses, fat, and protein).

Te size of these digesters differs wide-

ly. Millions of small digesters are used inconnection with family houses or smallfarms in Asian countries to produce gasfor cooking; medium sized digesters canbe found on farms around the world toproduce mainly electricity and heat, andbigger digesters are in use for the diges-tion of waste from cities and municipali-ties, be it sewage sludge, waste from thefood industry or collected from house-hold organic waste bins.

A biogas plant on a farm has differentelements such as the liquid manure store,the receiving area, the digester, the gasstorage and, in case of the combined heatand power (CHP) application, grid connec-tion for the electricity and a connection tothe heat user. Te cost of investment perkW installed electric capacity is about

Euro for an installation of about kW in size; the specic investment cost ishigher for smaller plants and lower for big-ger plants. [ ]

After production the raw biogas can becleaned and upgraded to methane; it isthen called biomethane, and in this pureform can be compressed and injected into

gas grids or used as transport fuel. Te en-ergy content of raw biogas varies between and kWh/Nm of biogas depending on

the composition; as an average kWh/Nm biogas is assumed (i.e., assuming methane content). For pure biomethanethe energy content is approximately kWh/m .

A typical landll also emits biogas pro-duced as a result of microbial decomposi-tion of wet organic matter in the absenceof oxygen; the gas is normally called land-ll gas, and for larger properly managedsites this is captured and used for energyproduction purposes (usually by fuelling aspark-ignition motor driving a generator),instead of being allowed to escape to theatmosphere and thus contribute to green-house gas emissions. On some landlls it

is simply ared so that the methane is con-verted to the less damaging greenhousegas carbon dioxide.

FEEDSTOCKBiogas can be produced from most bio-mass and waste materials regardless oftheir composition and over a large rangeof moisture contents (although very highmoisture content material of under drymatter reduces biogas yield) with limitedfeedstock preparation. Woody biomass isnot suitable for anaerobic biogas produc-tion due to its high lignin content. However, wood can be converted to methane bya thermal gasication process, the productof which is usually referred to as syntheticnatural gas or SNG (this process is not thesubject of this fact sheet).

Organic fraction in landfillsBy extracting and processing the land-ll gas (by removal of water and possiblyhydrogen sulphide) so it can be used forenergy purposes usually as a fuel for gasengine-driven generators. Moreover, land-ll gas utilization reduces green house gas(GHG) emissions.

Sewage sludgeRefers to the residual, semi-solid mate-rial left from wastewater treatment. Sew-age sludge can be used as a feedstock forbiogas. Tis is done in many wastewatertreatment plants. Te residues from diges-tion can be used as soil conditioner.

ManureManure is produced by intensively housedlivestock in some countries is stored onfarms for several months in liquid or solidform and then used as fertilizer. Duringstorage, anaerobic digestion can take placein the bottom layers of manure producingmethane that might be released to the at-mosphere if it were not used for energy orared. Blending manure with energy cropsor other waste streams for anaerobic di-gestion is an attractive option to increasebiogas production. [ ] In developing coun-tries, manure is often used in small fami-ly-scale anaerobic digesters and the gas ismostly used for cooking, with other appli-cations being domestic lighting or runningspark ignition engines.

TABLE 1: COMPOSITION OF BIOGAS, [2]

Matter %

Methane CH4 50 75

Carbon dioxide CO2 25 45

Water vapor, H2O 2-7

Nitrogen, N2 < 2

Oxygen, O2


3/7

3

Energy cropsEnergy crops (in the context of biogasproduction) are agricultural plants grownspecically for feedstock in biogas plants.

ypical energy crops in Europe and North America are maize and sweet sorghum;sugar beet is also gaining importance innorthern Europe. Te mix of manure andmaize is a common feedstock for biogasplants on farms in Europe.

Other agricultural feedstocksOther agricultural feedstocks in use forbiogas can be catch crops that are plantedafter the harvest of the main crop; theyallow a second harvest on the same pieceof land within one year. Ley crops (cropsplanted on land resting between commer-cial crop cycles) also have some potentialand are already used in some places. Alsogreen cuttings and other fresh leafy mate-

TABLE 3: EXAMPLES FOR AGRICULTURAL BIOGAS YIELDS [2]

Type Nm biogas

1 milking cow 20m liquid manure/a 500 1 pig 1.5 6 m liquid manure/a 42-168

1 cattle (beef) 3 -11t solid manure/a 240 880

100 chicken -1,8m dry litter 242

Maize silage 40 -60 green weight/ha 7040 - 10560

Grass 24 43 t fresh matter/ha 4118 - 6811

TABLE 4: DIFFERENT APPLICATIONS OF BIOGAS [4]

Production of heat for cooking (small units in houses, farms - particularly developed in India and China)

Heat and electricity: typical combined heat and power units using a gas engine driven genset on farms, landfills, etc.

Injection into the gas grid after upgrading to biomethaneTransportation fuel after upgrading, compressing

Industrial uses for high temperature heat and steam (displacing natural gas use)

For targeted electricity production to offset the variability of wind and PV electricity

rials coming from the maintenance of thelandscape, such as from trimming of trees,bushes and grass, can be used for biogasplants as well.

Waste streams for biogasDifferent by-products or residues of thefood processing and prepared food produc-tion industries breweries, sugar plants,fruit processing, slaughter houses, etc., but

P h o t o: S v e n s k B i o g a s

The biogas plant in the municipality of Linkping, Sweden. Sweden is a world leader in upgrading and use of biomethane for transport.Biogas covers today 1% of the total road trafc in Sweden.

How much biogas is needed for amotor-generator of 100 kW el outputcapacity? A biogas plant with an installed capac-ity of kW el, an electrical efficiencyof and an annual production of

. kWh electricity requires Nm biogas. Tis equals the biogas

output from a manure slurry of in-tensively housed milking cows, pigs or ha of maize.

BIOGAS YIELDS


4/7

4

1

2

4

3

5

also food waste, used kitchen oil, the organ-ic fraction of municipal solid waste (MSW)can all be used as biogas feedstock. [ ]

USE AND APPLICATIONBiogas covers a variety of markets, includ-ing electricity, heat and transportationfuels. Whereas using the gas for directcombustion in household stoves and gaslamps is common in some countries, pro-ducing electricity from biogas is still rela-tively rare in most developing countries. Inindustrialized countries, power generationis the main purpose of biogas plants; con-

version of biogas to electricity has becomea standard technology. o improve overallefficiency of biogas utilization, combinedheat and power plants are often used.

After fermentation the biogas is nor-mally cooled, dried of water vapour andcleaned of hydrogen sulphide to produce agood combustion gas for gas engines. Teillustration above gives an overview aboutthe different ways to use biogas.

Upgrading

Biogas produced from anaerobic digestioncannot be used directly as vehicle fuel orinjected into a gas grid; it must be upgrad-ed to biomethane rst. Te gas is cleanedof particles, water and hydrogen sulde toreduce the risk of corrosion. Te gas is up-graded by removing carbon dioxide to raise

the energy content and create a gas withconstant quality [ ] consisting of about

methane [ ].

Several techniques for removing carbondioxide from biogas exist today and theyare continually being improved. Tesemethods include water scrubbing, pres-sure swing absorption (PSA), organic phys-ical scrubbing, chemical scrubbing and up-grading using membrane technology.

Emerging biogas conceptsfor infrastructure and supplyDifferent requirements for biogas use,such as heat generation or upgrading theinjection into a gas grid, requires differentcongurations of the biogas plants loca-tions and size. Early on, when biogas wasbeginning to be used to produce energy,CHP units were often placed at the samelocation. More recently new concepts haveemerged involving the production of thebiogas in one place and the subsequenttransportation of the biogas to a centralCHP plant, or an upgrading station, locat-ed near a gas pipeline for injection into theregional gas grid.

Support policiesIt is true that modern biogas production isonly developing rapidly in regions with aconsistent and effective government sup-port policy. Te main elements of a typi-

cally successful support policy are:Guaranteed access to the electricity

and gas grid, reasonable feed-in tariffs for

electricity and biomethane, investmentgrants, education and training of the laborforce, support policies to include the useof heat, some variation of a carbon tax onequivalent fossil fuels, support for meth-ane fuelled vehicles.

As with natural gas, biogas (particularlyin its upgraded form) is a high quality en-ergy carrier. It should therefore primarilybe used for energy services that demandhigh quality energy such as combined heatand power generation, or transport.

THE GLOBALPOTENTIALTe feedstock is diverse. o quantify thepotential the following classication canbe used:

Agricultural feedstock such as; Manure By-products like straw, green mass fromcash crops, landscape management

Energy crops

Waste streams coming from; Organic fraction of Municipal SolidWaste (MSW)

Biodegradable fraction of industrialwaste (food industry)

Sewage sludge

Energy production in a biogas plant. [20]

Fuel crops

Feed

Stock farming

Slurry or manure

Preliminary tank

Organic waste

Fuel crops ororganic waste

Process heat

Fermenter Heat

Power

Generator

Gasmotor

Biogas lling station

Natural gas networkBiogas

Gas treatment system

CHP plant

1.

2.3.

5.

4.

1. The fermentation tank contains the micro-organisms that anaerobically digest the biomass(in a sealed light-proof vacuum) to produce the biogas and carbon dioxide.

2. Residual materials left over after fermentation can be used as fertiliser, substantially reducing the use ofmineral fertilizer in agriculture.

3. In a Combined Heat and Power (CHP) plant the biogas is combusted to produce both electricity and heat.

4. The Gas upgrading plant increases the methane content to 98% whilst improving the overall quality ofthe biogas by removing CO 2 and other impurities.

5. The upgraded biogas can then be fed directly into existing natural gas networks or can be used as atransport fuel.


5/7

5

Te potential is reported in units of bi-omethane ( m biomethane = . Nmbiogas) to make it readily comparable withnatural gas.

For the EU the potential, excludingenergy crops, was estimated as . billionm biomethane with . billion m comingfrom agriculture and . billion m fromthe waste sources [ ]. Te total potential,including energy crops on of the arableland, was estimated to be . billion m( PJ). Tis corresponds to of thepresent consumption of natural (fossil) gasin the European Union.

Several studies in Europe show that thepotential for biogas without using energycrops is of the order of , PJ per Millioninhabitants. Also different studies on thebiogas potential in China are available. Abrief summary is shown in table .

As seen in table , the potential of biogaswould be sufficient to cover , accordingto table of the global primary energy sup-ply of EJ in . [ ]

BIOGAS AROUNDTHE WORLDExperience with domesticbiogas technology inDeveloping Countries Around the world, the implementation ofdomestic biogas technology has occurredin countries where governments have beeninvolved in the subsidy, planning, design,construction, operation and maintenanceof biogas plants. Te giant biogas coun-tries China and India (April to March

) produced . million and ,biogas plants respectively in , arrivingat impressive cumulative numbers of .

million and . million units installed of allsizes from a few m volume upwards. [ ]

Te Netherlands Development Organi-zation, SNV, supports national programson domestic biogas that aim to establishcommercially viable domestic biogas sec-tors in which local companies market, in-stall and service biogas plants for house-holds in developing countries. Te coun-tries [ ] supported by SNV have installeda total of more than , plants by therst half of . Financial support wasprovided by a wide spectrum of nationaland international organizations.

The United StatesTe U.S. has over , sites producingbiogas: anaerobic digesters on farms,approximately , anaerobic digestersat wastewater treatment plants (only currently use the biogas they produce) and

landll gas projects. By comparison,Europe has over , operating digest-ers; some communities are essentially fos-sil fuel free because of them. [ ]

EuropeIn order to reach the EU member state tar-gets for renewable energies for and tofulll European waste management direc-tive requirements, anaerobic digestion isseen to be one of the key technologies.

In total, . billion m of biogas, cor-responding to . billion m biomethane,was produced in in the EuropeanUnion.Te electricity production from bi-ogas in , with a growth rate of .reached . Wh, while over the same pe-riod biogas heat sales to factories or heat-ing networks increased by . [ ]

Germany: Industrial scaleGermany is Europes biggest biogas pro-ducer and the market leader in biogas tech-nology. [ ] In , the number of biogasplants reached , including unitsproducing biomethane. [ ]

Te total electric output produced bybiogas in was Wh, equating tothe supply of . million houses with elec-tricity. [ ] Biogas already provides morethan of the whole of Germanys elec-tricity consumption, as well as signicantamounts of industrial heat, transport fu-

els, and volume injected into the naturalgas grid. [ ]

Sweden: World leader in theuse of biogas for transportSweden is a world leader in upgrading anduse of biomethane for transport, and hasmany biogas vehicles, including privatecars, buses, and even a biogas train and abiogas-powered touring car team. At theend of , there were nearly , gasvehicles in Sweden: buses, nearly trucks and the rest being cars and light trans-port vehicles (often part of municipal eets).Compared to the end of (one year lat-er), the number of gas vehicles increased byabout percent [ ]. Over a similar periodof time the number of upgrading plants hasreached plants, representing a growthin numbers since .

China: Leader inhousehold biogas plantsIn China the renewable energy policy isdriving the steady development and imple-mentation of biogas. As of , China hasnearly million small biogas digesters

TABLE 5: POTENTIAL FOR BIOGAS IN PJ (BILLION M BIOMETHANE), CH4: EU 27, CHINA, WORLD

Type of resource EU 27 [4]PJ

EU 27 [4]Billion m

CH4

China [8,9]PJ

China [8,9]Billion m

CH4

World [7]PJ

World [7]Billion m

CH4

Manure 738 20.5 2591 72

Residues (straw from grain, corn, rice, landscape cleaning) 407 11.3 1152 32Energy crops 978 27,2 1799 50

Total from agriculture 2123 59 5542 154 22674 630

Urban waste (organic fraction of MSW) 360 10 2591 72

Agro-industry waste (organic fraction) 108 3 1152 32

Sewage sludge 216 6 576 16

Total waste, billion m 3 CH4 684 19 4319 120 13316 370

Total (agriculture and waste) 2807 78 9861 274 35990 1000

Total in EJ 2.8 9.9 35,9


6/7

6

in operation, producing biogas for house-holds, for cooking, and a further ,small, medium and large scale installationsproducing biogas for industrial purposes.

otal biogas output in is estimated at billion m biogas, equivalent to billion

m biomethane. China has ambitious tar-

gets for [ ]: 10,000 new agricultural biogas projects 6,000 new industrial biogas projects Installed biogas generator capacity: 3000 MW Total biogas output: 50 billion m biogas,equivalent to billion m of biomethane.

In Chine it is envisaged that in the futurea percentage of the biogas produced will beupgraded and subsequently injected intothe gas grid network for use as transportfuel, CHP or industry.

Global productionExact global data on the energy supply bybiogas is not available. It can be roughlycalculated that globally biogas delivers

billion m biomethane equivalent, cor-responding to PJ, thus, onlya very small fraction of the potential ofbiogas for energy has been realized so far.

THE BENEFITS OFBIOGAS TECHNOLOGYBiogas plants provide multiple benets atthe household, local, national, and inter-national level. Tese benets are appreci-ated differently in different countries, andcan be classied according to their impacton energy security, employment, environ-ment and poverty.

Environmental benefits Anaerobic digestion of wastes results in re-duced contamination of groundwater, sur-face water, and other resources. Anaerobicdigestion effectively destroys such harmfulpathogens as E.coli and M. avium paratu-burculosis. Effluent from biogas digesterscan serve as high quality organic ferti-lizer, displacing import or production ofsynthetic nitrogenous fertilisers. Finally,anaerobic digestion serves to reduce thevolume of wastes and the associated prob-lem of their disposal.

The impact on thegreenhouse effectBiogas produced on a sustainable basis cansignicantly reduce greenhouse gas (GHG)

emissions. Of the worldwide million tonsof methane emissions per year generatedfrom the different animal waste manage-ment systems like solid storage, anaerobiclagoon, liquid/slurry storage, pasture etc.about half could be avoided through anaer-obic treatment. It is estimated that throughanaerobic treatment of animal waste andenergy use of the methane produced, about

, million tons of CH emission can beavoided worldwide per year. [ ]

Economic and social benefitsIncreased employmentPromoting biogas production from or-ganic wastes and sustainably producedfeedstocks results in creation of perma-nent jobs and regional development. Teinvolvement of many interested parties in

planning, construction, cost estimation,production, control and distribution isneeded to ensure the successful develop-ment of biogas technology.

Sustainable energy resource:Te development of biogas represents a

strategically important step away fromdependence on fossil fuels whilst contrib-uting to the development of a sustainableenergy supply and enhanced energy secu-rity in the long-term.

Decentralized energy generation:One of the advantages of biogas technol-ogy is that it can be established locally,without the need for long-distance trans-portation or import of raw materials.Small or medium-sized companies and lo-cal authorities can establish biogas plants

anywhere (i.e. they need not be sited inany particular location; for example, in orclose to large cities).

Sustainable waste management:Utilizing organic wastes reduces theamount that must be taken care of in someother way, for example by combustion, ortransport to landlls.

Clean fuel for industry:Methane is a fuel in demand by industry;partly because it is a gas that gives a high

quality combustion that can be preciselycontrolled. Methane burns with a cleanand pure ame, which means that boilersand other equipment are not clogged bysoot and cinders. Tis leads to a cleanerworkplace environment and possibly a re-duced maintenance costs for the plant.

The WBA advocates that Biogas production should be an impor-tant part of the strategy to reduce GHG emissions and improveenergy security everywhere, because biogas production usesfeedstock that otherwise is not used at all but emits greenhousegases through decay and causes a number of environmentalproblems. Biogas also replaces fossil fuels further reducing emis-sions of greenhouse gases.

The deployment of biogas technology requires a decentralized ap-proach involving many new entrepreneurs. The construction andsuccessful operation of biogas plants needs an integrated supportpolicy by the governments comprising the following elements:

Training and education of the labor force

Monitoring and continuous improvements in the plants operation Access to the electricity and the gas grid

Reliable long-lasting financial support in the form of tariffs forthe electricity or biomethane sold to the grid and to vehicle fuels.

WBA advocates that each country sets up a biogas developmentplan with the target to use at least 30% of the biogas potential by2030. Such a plan should not only contain quantitative targets butalso an array of measures and a system of monitoring to reachthe targets. This should be valid for countries in the developingworld as well as the developed world.

The global institutions such as the organization of the UN with itsaffiliates, the World Bank, and the coming Green Climate Fund,should offer financing instruments that support small and me-dium sized biogas plants and not only large-scale applications.

WBA is convinced that such an integrated approach to the devel-opment of biogas would enhance the national energy security,generate employment (especially in rural areas) and contributepositively to climate change mitigation.n

POSITION OF WBA


7/7

7

SOURCES. Te future of Biogas in Europe, Holm-

Nielsen et al.

. Broschre Biogas Fachagenturnachwachsende Rohstoffe; Gzow-Przen. Germany. . Auage,

. michian university, April , onlineavailable at: http://www.thebioenergysite.com/articles/ /generating-biogas-the-best-feedstock-materials, accessed November

. A Biogas Road Map for Europe. AE-BIOM. Brussels. .

. http://www.sgc.se/dokument/Evalua-tion.pdf

. IEA , Key World Energy Statistics

. WBA Calculations

. B.Raninger et.oth.Biogas to grid inChina:challenges and opportunities ofa new marketfrom industrial large scalebiogas plants in Biogas Engineering and Application, volume . Bejing .

FURTHER READINGEurobserver: biogas Barometer,

http://www.eurobserv-er.org/pdf/baro biogas.pdf IEA Bioenergy: Biogas from Energy Crop Digestion,http://www.iea-biogas.net/_download/publi-task /Digestate_Brochure_Revised_ - .pdf

IEA Bioenergy: Utilisation of digestate from biogas plant as biofertiliser,http://www.iea-biogas.net/_download/publi-task /energycrop_def_Low_Res.pdf

. ong Boitin. Biogas echnology andMarket status in China. BI rd An-nual World Congres of Bioenergy. Nan- jing.,

. http://www.snvworld.org/en/regions/world/news/production-rate-of-biogas-plants-increased .UOvxBbv mkA

. In Asia: Nepal,Vietnam,Bangladesh,Bhutan, Cambodia, LaoPDR, Pakistanand Indonesia. In Af-rica; Rwanda,Senegal, Burkina Faso,Ethiopia, anzania,Uganda, Kenya, Beninand Cameroon.

. http://www.americanbiogascouncil.org/pdf/biogas .pdf

. http://www.eurobserv-er.org/pdf/baro biogas.pdf

. http://www.renewables-made-in-

germany.com/en/renewables-made-in-germany-start/bioenergy/biogas/market-development.html

. http://www.balticbiogasbus.eu/web/Upload/doc/Wakbrzych_ _July_ /Grzelak.pdf

. http://www.iea-biogas.net/_down-load/publications/country-reports/ /Country Report Germany_Bernd Linke_Moss_ - .pdf

. http://www.crossborderbioenergy.eu/leadmin/crossborder/Biogas_Mar-ketHandbook.pdf

. http://www.gasbilen.se/Att-tanka-pa-miljon/Fordonsgas-i-siffror/Gasbi-larUtveckling and Energimyndighetens-statistik Produktionochanvndningavbiogas r (ES : )

. Cassada M. E., Saey L.M.Jr.,: Global Methane Emissions

from Livestock and Poultry Manure.EPA CX- - [online] avail-able at: https://energypedia.info/wiki/Environmental_Benets_of_Biogas_

echnology cite_ref-Cassada_M._E.. C_

Saey_L.M.Jr.. C_ :_ - . [accessedJanuary ]

. Energy production in a biogas plant, juwi energy, [online] available at: http://in.preview.juwi.com/bio_energy/technics.html. [accessed May]

ANDRITZ Group the Official supporter of WBA:

Silver supporter of WBA:

World Bioenergy Association, Hollndargatan 17, SE 111 60 Stockholm, SwedenTel. + 46 (0)8 441 70 80, [email protected], www.worldbioenergy.org

factsheet_biogas_6.pdf

Documents