Difference between revisions of "Carbon Markets for Biogas Digesters"

From energypedia
***** (***** | *****)
m
***** (***** | *****)
Line 11: Line 11:
 
*[http://www.kfw.de/DE_Home/KfW-Klimaschutzfonds/PDF/PoA_BlueprintBook_Nov2010.pdf KfW PoA Blueprint Book 2nd Edition] - Includes a section on PoA issues for domestic biogas plants
 
*[http://www.kfw.de/DE_Home/KfW-Klimaschutzfonds/PDF/PoA_BlueprintBook_Nov2010.pdf KfW PoA Blueprint Book 2nd Edition] - Includes a section on PoA issues for domestic biogas plants
 
*[[Environmental Benefits of Biogas Technology|Environmental Benefits of Biogas Plants]]
 
*[[Environmental Benefits of Biogas Technology|Environmental Benefits of Biogas Plants]]
 +
 +
 +
= Background<br/> =
 +
 +
Every industrial process results not only in the products wanted, but also in by-products, wastes and emissions. Amongst the emissions, normally also greenhouse gases occur. Hence, every industrial process is climate relevant, for greenhouse gases are emitted as a result of the technological processes taking place. Which substance is emitted and in which amount it is emitted depends on the specific process and the conditions of its application. Thus, the choice of the technology, the apparatus, the cleaning devise, etc. may influence the climate effects of the production process. An optimisation of the process with reference to a decision criteria reflecting the climate effects is thus a necessary precondition for the choice of the best technologies (see chapter 8.1). Some examples of industrial processes are given in the next chapter. The data used for description of the processes are either derived from assumptions of chemical reactions or upon published empirical data<ref>Integrated pollution and prevention control. BREF, Madrid, 2001.</ref>. The emissions considered here are by-products of the industrial process itself. Typically, in such processes, raw materials are transformed from one state to another in the end product. This transformation is accompanied by the release of emissions, such as carbon dioxide (CO<sub>2</sub>), methane (CH<sub>4</sub>), or nitrous oxide (N<sub>2</sub>O). They are the reason of the [http://en.wikipedia.org/wiki/Greenhouse_effect greenhouse effect] of the process.
 +
 +
<br/>
 +
 +
The combustion of biogas results in greenhouse gases emissions. But these emissions are not addressed to climate change. As those emissions are considered to close the loop of the natural carbon cycle. The reason is, that they origin from atmospheric carbon dioxide from which they were taken by photosynthesis. CO2 produced from biogenic sources under natural conditions will return to the atmosphere at the same amount. If there are metabolites or results from processes other than CO2, such as methane, N2O, NOx, etc., than these substances are considered climate relevant and their greenhouse gas effects must be balanced <ref>FECC, GTZ, KNOTEN Weimar, 2009: VII Climate Change. Workshop „Biogas-Plant-technology planning, Beijing,</ref>.
 +
 +
<br/>
 +
 +
= Climate relevant emissions of a biogas plant<br/> =
 +
 +
[[File:Correlation retention time & residual gas potential.jpg|thumb|right|Correlation retention time & residual gas potential.JPG]]In comparison with untreated manure, methane formation from digested manure is considerably reduced by the [[Biogas Basics|anaerobic process]], because some of the organic matter contained in the substrate has already been metabolised in the digester, which means that there is significantly less easily degradable carbon in the storage tank.
 +
 +
<br/>
 +
 +
<br/>
 +
 +
<br/>
 +
 +
'''The extent to which emissions of methane are reduced will depend decisively on the degree to which the organic matter has been degraded''' '''and consequently also on the retention time of the substrate in the digester.''' For example, it has been demonstrated in various studies that digestates with a short digestion phase, i.e. a short retention time in the digester, will emit more CH<sub>4</sub> than digestates with a longer retention time in the digester (see graph<ref>FNR (2009): Ergebnisse des Biogasmessprogramm II,fckLRGülzow</ref>).
 +
 +
<br/>If the retention time is very short, there can be increased emissions of methane in comparison with untreated manure if substrate that has just been inoculated with methane-forming bacteria is removed from the digester after a short time and transferred to digestate storage <ref>Clemens, J., Wolter, M., Wulf, S., Ahlgrimm, H.-J. (2002): Methan- und Lachgas-Emissionen bei der Lagerung und Ausbringung von Wirtschaftsdüngern, in: KTBL-Schrift 406, Emissionen der Tierhaltung,fckLRpp. 203-214</ref>. Short-circuit streams should therefore be avoided. To estimate the methane emissions from digestate,<br/>it is possible to use the results from batch digestion experiments with digestates at 20-22 °C <ref>FNR (2009): Ergebnisse des Biogasmessprogramm II, Gülzow</ref> since this more or less corresponds to the temperature in a digestate storage tank under real-world conditions. On the other hand, the values for residual<br/>gas potential obtained under mesophilic conditions (37 °C) cannot be relied on with regard to actual emissions. Nevertheless, they can still give an indication of the efficiency of the digestion process, because they reflect the biomass potential still present in the digestate, i.e. the biomass potential that was not converted in the digester. Both parameters depend, however, on process control and also on the substrates used at the particular plant. Consequently, the values given in Table 10.6 should be regarded<br/>merely as a guide.<br/>Multi-stage plants tend to exhibit a lower residual gas potential both at 20-22 °C and also at 37 °C. This is due above all to the fact that a multi-stage plant has a higher retention time, which has the effect of reducing the residual gas potential. Owing to the high greenhouse potential of CH<sub>4 </sub>'''(1 g CH<sub>4</sub> is equivalent to 23 g CO<sub>2</sub>)''', it is desirable to reduce or prevent CH4 emissions from digestate storage tanks.
 +
 +
Plants without gas-tight end storage should, in addition to multi-stage operation (digester cascade), meet at least one of the following requirements:
 +
 +
<br/>
 +
*'''average hydraulic retention time of the total substrate'''
 +
*'''volume of at least 100 days at a continuous'''
 +
*'''digestion temperature throughout the year of at least 30 °C or'''
 +
*'''digester [[Operation of biogas reactors|organic loading rate]] < 2.5 kg VS/Nm<sup>3</sup>/d'''
 +
 +
<br/>Calculation of the substrate volume must take account of all inputs into the digestion tank(s) (including, for example, water and/or recirculate). If the above-mentioned requirements are not met, methane emissions must be expected to exceed the average values. In such cases, it is advisable to retrofit the digestate storage tank(s) with a gas-tight seal2 for at least the first 60 days of required digestate storage.
 +
 +
<br/>
 +
 +
For a complete observation on emissions related to a biogas plant constructional and logistical aspects of the volume flow have to be considered.
 +
 +
<br/>
 +
 +
= [[File:Ghg emission from organic waste utilisation.JPG|frame|center|Ghg emission from organica waste utilisation.JPG]]Emission Reduction of environmental impacts =
 +
 +
The minimisation of environmental impacts aims at reducing the effects of the plant on the environment. The release of pollutants to the air, water and soil needs to be considered.
 +
*Seepage water (collection and utilisation of silage seepage water, runoff from storage areas)
 +
*Methane emissions from the biogas plant (provide digestate storage tank with gas-tight cover, identify leaks, slip from gas utilisation, engine settings, maintenance work)
 +
*Formaldehyde, NOx, oxides of sulphur, carbon monoxide (CHP unit only, engine settings, exhaust gas treatment)
 +
*Odour emissions (covered loading facility, storage areas and digestate storage tank, separated fermentation residues)
 +
*Noise emissions
 +
*After the application of fermentation residues: ammonia emissions, nitrous oxide emissions (application techniques and incorporation of the residues).
 +
 +
Not only do uncontrolled emissions of silage seepage water, methane and ammonia have a detrimental impact on the environment, they also signify losses in terms of the efficiency of the plant as a whole. In this respect, structural or operational measures to reduce emissions can certainly pay off financially (for example a gas-tight cover for a digestate storage tank). As a general rule the plant should be regularly checked for possible emissions. In addition to environmental and economic considerations, it is often also necessary to take safety matters into account as well.
 +
 +
<br/>[http://giz.energypedia.info/index.php/Portal:GIZ_Bio_Energy ►Return to Main Page]<br/>
 +
 +
<br/>
 +
 +
= Web<br/> =
 +
 +
Guidelines for the selection and use of fuels and raw materials in cement manufacturing process. World business council for sustainable development, Draft report, Version 1, 12/2005. [http://www.wbcsdcement.org/pdf/tf2/tf2_guidelines.pdf http://www.wbcsdcement.org/pdf/tf2/tf2_guidelines.pdf]
 +
 +
<br/>
 +
 +
Cement sustainability initiative. [http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf]
 +
 +
<br/>
 +
 +
Best available technique reference document Iron and Steel, EU commission, Madrid, 2002. [http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf]
 +
 +
<br/>
 +
 +
Environmental Protection agency (EPA): US emission inventory2006. [http://yosemite.epa.gov/oar/globalwarming.nsf/content/ResourceCenterPublicationsGHGEmissionsUSEmissionsInventory2006.html http://yosemite.epa.gov/oar/globalwarming.nsf/content/ResourceCenterPublicationsGHGEmissionsUSEmissionsInventory2006.html]
 +
 +
<br/>
 +
 +
International Non-CO2 greenhouse Gas marginal abatement report. Draft methane and nitrous from Non-agricultural sources, April 2005. [http://www.epa.gov/methane/pdfs/chapter3_landfill.pdf http://www.epa.gov/methane/pdfs/chapter3_landfill.pdf]
 +
 +
<br/>
 +
 +
United Nations Environmental Program (UNEP). International life cycle partnership . www.uneptie.org/sustain/lcinitiative<br/>[http://www.uneptie.org/pc/sustain/reports/lcini/LCIni_Flyer03.pdf http://www.uneptie.org/pc/sustain/reports/lcini/LCIni_Flyer03.pdf]
 +
 +
<br/>
 +
 +
US Environmental Protection agency: Calculating Greenhouse Gas Emissions with the Excel. Version of the WAste Reduction Model (WARM). [http://www.epa.gov/globalwarming/actions/waste/warm.htm http://www.epa.gov/globalwarming/actions/waste/warm.htm] and [http://yosemite.epa.gov/oar/globalwarming.nsf/content/ActionsWasteToolsReports.html http://yosemite.epa.gov/oar/globalwarming.nsf/content/ActionsWasteToolsReports.html]
 +
 +
<br/>
 +
 +
US Environmental Protection agency: Solid waste Management and greenhouse gases. A life-cycle assessment of emissions and sinks. www.epa.gov/mswclimate/greengas.pdf
 +
 +
<br/>
 +
 +
Society of Environmental Toxicology and Chemistry (SETAC). [http://www.setac.org http://www.setac.org]
 +
 +
<br/>
 +
 +
BASF: Eco-efficiency analysis. [http://corporate.basf.com/en/sustainability/oekoeffizienz/?id=noAIH8fMmbcp1tZ http://corporate.basf.com/en/sustainability/oekoeffizienz/?id=noAIH8fMmbcp1tZ]
 +
 +
<br/>
 +
 +
Marland, G. et. Al.: Global, regional, and national fossil fuel CO2-emissions (2003). [http://cdiac.esd.ornl.gov/trends/emis/meth_reg.htm http://cdiac.esd.ornl.gov/trends/emis/meth_reg.htm]
 +
 +
<br/>
 +
 +
EEB position on Biomass and bio-fuels: the need of well defined sustainability criteria, December, 2005: [http://www.eeb.org/activities/agriculture/EEB-position-on-bioenergy-191205.pdf http://www.eeb.org/activities/agriculture/EEB-position-on-bioenergy-191205.pdf]
 +
 +
<br/>
 +
 +
Directive 2003/30/EC of 8 May 2003 on the promotion of the use of bio-fuels or other renewable fuels for transport (OJL 123, 17.5.2003. [http://europa.eu.int/eur-lex/pri/en/oj/dat/2003/l_123/l_12320030517en00420046.pdf http://europa.eu.int/eur-lex/pri/en/oj/dat/2003/l_123/l_12320030517en00420046.pdf]
 +
 +
<br/>
 +
 +
Directive 2003/96/EC of 27 October 2003 restructuring the Community framework for the taxation of energy products and electricity (OJL 283, 31.10.2003). [http://eur-lex.europa.eu/LexUriServ/site/en/com/2004/com2004_0042en01.pdf http://eur-lex.europa.eu/LexUriServ/site/en/com/2004/com2004_0042en01.pdf]
 +
 +
<br/>
 +
 +
UK Renewable Transport Fuel Obligation (RTFO) feasibility report: [http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610329-03.hcsp#P37_6185 http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610329-03.hcsp#P37_6185]
 +
 +
<br/>
 +
 +
E4tech: Feasibility report on certification for a renewable transport fuel obligation. Final report, June 2005. [http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610366.pdf http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610366.pdf]
 +
 +
<br/>
 +
 +
International Energy agency: Bio-fuels for transport - an international perspective. Paris, 2004. [http://www.oecdobserver.org/news/fullstory.php/aid/1647/Biofuels_for_transport.html http://www.oecdobserver.org/news/fullstory.php/aid/1647/Biofuels_for_transport.html]
 +
 +
<br/>
 +
 +
= DMS<br/> =
 +
 +
[https://dms.gtz.de/livelink-ger/livelink.exe?func=ll&objId=73011173&objAction=browse&viewType=1 For further information an climate protection click here.]
  
 
<br/>
 
<br/>
  
−
= References =
+
= References<br/> =
  
 
<references />
 
<references />
  
−
<br/>[[Biogas|⇒ Back to Biogas Section]]
+
[[Category:Biogas]]
−
 
+
[[Category:Carbon_Market]]
 +
[[Category:Financing_Biogas]]
 +
[[Category:Financing_and_Funding]]
 
[[Category:Clean_Development_Mechanism_(CDM)]]
 
[[Category:Clean_Development_Mechanism_(CDM)]]
−
[[Category:Financing_and_Funding]]
 
−
[[Category:Financing_Biogas]]
 
−
[[Category:Carbon_Market]]
 
−
[[Category:Biogas]]
 

Revision as of 22:34, 20 January 2014

Overview

Carbon markets constitute a new financing option for biogas dissemination projects. The number of biogas projects that are under validation, requesting registration or registered is 516, or 11.6% of the CDM projects (UNEP Risoe, March 2009). However, the highest number of biogas projects is concentrated in 5 countries, namely: Thailand, India, China, Malaysia, and the Philippines. Most of the registered projects are situated on the commercial livestock farms and the main emission reduction takes place due to switch in those cases where biogas is used for energy generation. By installing the biogas unit the animal manure that was previously deposited in an open lagoon in the baseline scenario is fermented in the biogas digester and the methane emission is avoided. The generated biogas can either be flared or used for energy generation. Biogas can be used to replace fossil fuels for heating purposes, or for producing heat and electricity by introducing a CHP unit. Apart from the benefits of replacing fossil fuels and improving the manure management system, the by-product after the fermentation of the manure is a digestate (bio-slurry) which could be used as high nutrient organic fertilizer.


Further Information


Background

Every industrial process results not only in the products wanted, but also in by-products, wastes and emissions. Amongst the emissions, normally also greenhouse gases occur. Hence, every industrial process is climate relevant, for greenhouse gases are emitted as a result of the technological processes taking place. Which substance is emitted and in which amount it is emitted depends on the specific process and the conditions of its application. Thus, the choice of the technology, the apparatus, the cleaning devise, etc. may influence the climate effects of the production process. An optimisation of the process with reference to a decision criteria reflecting the climate effects is thus a necessary precondition for the choice of the best technologies (see chapter 8.1). Some examples of industrial processes are given in the next chapter. The data used for description of the processes are either derived from assumptions of chemical reactions or upon published empirical data[1]. The emissions considered here are by-products of the industrial process itself. Typically, in such processes, raw materials are transformed from one state to another in the end product. This transformation is accompanied by the release of emissions, such as carbon dioxide (CO2), methane (CH4), or nitrous oxide (N2O). They are the reason of the greenhouse effect of the process.


The combustion of biogas results in greenhouse gases emissions. But these emissions are not addressed to climate change. As those emissions are considered to close the loop of the natural carbon cycle. The reason is, that they origin from atmospheric carbon dioxide from which they were taken by photosynthesis. CO2 produced from biogenic sources under natural conditions will return to the atmosphere at the same amount. If there are metabolites or results from processes other than CO2, such as methane, N2O, NOx, etc., than these substances are considered climate relevant and their greenhouse gas effects must be balanced [2].


Climate relevant emissions of a biogas plant

File:Correlation retention time & residual gas potential.jpg
Correlation retention time & residual gas potential.JPG

In comparison with untreated manure, methane formation from digested manure is considerably reduced by the anaerobic process, because some of the organic matter contained in the substrate has already been metabolised in the digester, which means that there is significantly less easily degradable carbon in the storage tank.




The extent to which emissions of methane are reduced will depend decisively on the degree to which the organic matter has been degraded and consequently also on the retention time of the substrate in the digester. For example, it has been demonstrated in various studies that digestates with a short digestion phase, i.e. a short retention time in the digester, will emit more CH4 than digestates with a longer retention time in the digester (see graph[3]).


If the retention time is very short, there can be increased emissions of methane in comparison with untreated manure if substrate that has just been inoculated with methane-forming bacteria is removed from the digester after a short time and transferred to digestate storage [4]. Short-circuit streams should therefore be avoided. To estimate the methane emissions from digestate,
it is possible to use the results from batch digestion experiments with digestates at 20-22 °C [5] since this more or less corresponds to the temperature in a digestate storage tank under real-world conditions. On the other hand, the values for residual
gas potential obtained under mesophilic conditions (37 °C) cannot be relied on with regard to actual emissions. Nevertheless, they can still give an indication of the efficiency of the digestion process, because they reflect the biomass potential still present in the digestate, i.e. the biomass potential that was not converted in the digester. Both parameters depend, however, on process control and also on the substrates used at the particular plant. Consequently, the values given in Table 10.6 should be regarded
merely as a guide.
Multi-stage plants tend to exhibit a lower residual gas potential both at 20-22 °C and also at 37 °C. This is due above all to the fact that a multi-stage plant has a higher retention time, which has the effect of reducing the residual gas potential. Owing to the high greenhouse potential of CH4 (1 g CH4 is equivalent to 23 g CO2), it is desirable to reduce or prevent CH4 emissions from digestate storage tanks.

Plants without gas-tight end storage should, in addition to multi-stage operation (digester cascade), meet at least one of the following requirements:


  • average hydraulic retention time of the total substrate
  • volume of at least 100 days at a continuous
  • digestion temperature throughout the year of at least 30 °C or
  • digester organic loading rate < 2.5 kg VS/Nm3/d


Calculation of the substrate volume must take account of all inputs into the digestion tank(s) (including, for example, water and/or recirculate). If the above-mentioned requirements are not met, methane emissions must be expected to exceed the average values. In such cases, it is advisable to retrofit the digestate storage tank(s) with a gas-tight seal2 for at least the first 60 days of required digestate storage.


For a complete observation on emissions related to a biogas plant constructional and logistical aspects of the volume flow have to be considered.


File:Ghg emission from organic waste utilisation.JPG
Ghg emission from organica waste utilisation.JPG
Emission Reduction of environmental impacts

The minimisation of environmental impacts aims at reducing the effects of the plant on the environment. The release of pollutants to the air, water and soil needs to be considered.

  • Seepage water (collection and utilisation of silage seepage water, runoff from storage areas)
  • Methane emissions from the biogas plant (provide digestate storage tank with gas-tight cover, identify leaks, slip from gas utilisation, engine settings, maintenance work)
  • Formaldehyde, NOx, oxides of sulphur, carbon monoxide (CHP unit only, engine settings, exhaust gas treatment)
  • Odour emissions (covered loading facility, storage areas and digestate storage tank, separated fermentation residues)
  • Noise emissions
  • After the application of fermentation residues: ammonia emissions, nitrous oxide emissions (application techniques and incorporation of the residues).

Not only do uncontrolled emissions of silage seepage water, methane and ammonia have a detrimental impact on the environment, they also signify losses in terms of the efficiency of the plant as a whole. In this respect, structural or operational measures to reduce emissions can certainly pay off financially (for example a gas-tight cover for a digestate storage tank). As a general rule the plant should be regularly checked for possible emissions. In addition to environmental and economic considerations, it is often also necessary to take safety matters into account as well.


►Return to Main Page


Web

Guidelines for the selection and use of fuels and raw materials in cement manufacturing process. World business council for sustainable development, Draft report, Version 1, 12/2005. http://www.wbcsdcement.org/pdf/tf2/tf2_guidelines.pdf


Cement sustainability initiative. http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf


Best available technique reference document Iron and Steel, EU commission, Madrid, 2002. http://www.wbcsdcement.org/pdf/tf1/tf1_guidelines.pdf


Environmental Protection agency (EPA): US emission inventory2006. http://yosemite.epa.gov/oar/globalwarming.nsf/content/ResourceCenterPublicationsGHGEmissionsUSEmissionsInventory2006.html


International Non-CO2 greenhouse Gas marginal abatement report. Draft methane and nitrous from Non-agricultural sources, April 2005. http://www.epa.gov/methane/pdfs/chapter3_landfill.pdf


United Nations Environmental Program (UNEP). International life cycle partnership . www.uneptie.org/sustain/lcinitiative
http://www.uneptie.org/pc/sustain/reports/lcini/LCIni_Flyer03.pdf


US Environmental Protection agency: Calculating Greenhouse Gas Emissions with the Excel. Version of the WAste Reduction Model (WARM). http://www.epa.gov/globalwarming/actions/waste/warm.htm and http://yosemite.epa.gov/oar/globalwarming.nsf/content/ActionsWasteToolsReports.html


US Environmental Protection agency: Solid waste Management and greenhouse gases. A life-cycle assessment of emissions and sinks. www.epa.gov/mswclimate/greengas.pdf


Society of Environmental Toxicology and Chemistry (SETAC). http://www.setac.org


BASF: Eco-efficiency analysis. http://corporate.basf.com/en/sustainability/oekoeffizienz/?id=noAIH8fMmbcp1tZ


Marland, G. et. Al.: Global, regional, and national fossil fuel CO2-emissions (2003). http://cdiac.esd.ornl.gov/trends/emis/meth_reg.htm


EEB position on Biomass and bio-fuels: the need of well defined sustainability criteria, December, 2005: http://www.eeb.org/activities/agriculture/EEB-position-on-bioenergy-191205.pdf


Directive 2003/30/EC of 8 May 2003 on the promotion of the use of bio-fuels or other renewable fuels for transport (OJL 123, 17.5.2003. http://europa.eu.int/eur-lex/pri/en/oj/dat/2003/l_123/l_12320030517en00420046.pdf


Directive 2003/96/EC of 27 October 2003 restructuring the Community framework for the taxation of energy products and electricity (OJL 283, 31.10.2003). http://eur-lex.europa.eu/LexUriServ/site/en/com/2004/com2004_0042en01.pdf


UK Renewable Transport Fuel Obligation (RTFO) feasibility report: http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610329-03.hcsp#P37_6185


E4tech: Feasibility report on certification for a renewable transport fuel obligation. Final report, June 2005. http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_610366.pdf


International Energy agency: Bio-fuels for transport - an international perspective. Paris, 2004. http://www.oecdobserver.org/news/fullstory.php/aid/1647/Biofuels_for_transport.html


DMS

For further information an climate protection click here.


References

  1. ↑ Integrated pollution and prevention control. BREF, Madrid, 2001.
  2. ↑ FECC, GTZ, KNOTEN Weimar, 2009: VII Climate Change. Workshop „Biogas-Plant-technology planning, Beijing,
  3. ↑ FNR (2009): Ergebnisse des Biogasmessprogramm II,fckLRGülzow
  4. ↑ Clemens, J., Wolter, M., Wulf, S., Ahlgrimm, H.-J. (2002): Methan- und Lachgas-Emissionen bei der Lagerung und Ausbringung von Wirtschaftsdüngern, in: KTBL-Schrift 406, Emissionen der Tierhaltung,fckLRpp. 203-214
  5. ↑ FNR (2009): Ergebnisse des Biogasmessprogramm II, Gülzow
Retrieved from "https://energypedia.info/index.php?title=Carbon_Markets_for_Biogas_Digesters&oldid=69528"