Sustainability of biogas plants in organic farming


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This presentation shows the outcome of the SUSTAINGAS “Report on analysis of sustainability performance of organic biogas plants”. It was prepared by Frank Hofmann, Consultant Bioenergy at Ecofys. The analysed categories were greenhouse gas balance, sustainability issues of different substrates, farmland fertility, food vs fuel, biodiversity, water quality, fossil energy free farms and socio economic aspects. The report “development of recommendations and strategies to stakeholders” is available on the website:

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Sustainability of biogas plants in organic farming

  1. 1. Sustainability of Biogas Plants in Organic Farming SUSTAINGAS Workshop, Austria Frank Hofmann Ecofys Germany GmbH
  2. 2. Sustainability of Biogas Plants in Organic Farming Sustainability criteria Life Cycle Assessment for 12 model biogas plants Further Sustainability aspects Soil quality Food vs Feed Water quality Biodiversity Independence from fossile energy Socioeconomic effects
  3. 3. Sustainability Criteria RED: Biomass for utilization as fuel and bioliquids are subject to sustainability criteria Less GHG-effects to fossil fuel reference Land use requirements must not have negative impacts to biodiversity or carbon stocks Sustainable agricultural practice Introduction of sustainability criteria for biomass and biogas is under discussion, at EU-level Organic biogas can be produced sustainably
  4. 4. Sustainability Criteria Sustainability is mainly influenced through the use of input material Existing agricultural ILUC + Food land Energy crops Idle and marginal Envir. land Aspects Harvesting Recycling Aspects LUC Biodiv. Cascading & residues competition Social GHG Balance Animal excrements Catch crops Food industry and municipal residues Feedstock Sustainability issues © ECOFYS
  5. 5. LCA/ GHG-Emission Accounting Definition of 12 biogas plant models LCA Methodology Calculation according to „typical German“ Methodologies Calculation corresponding to RED and COM(2010)11 SUSTAINGAS GHG-tool based on BioGrace tool ( Adaptations in the SUSTAINGAS calculation to RED/COM Methodology: GHG emissions are attributed to electricity. Emission reductions from substituting fossil based heat are included as credit. GHG-emission savings conneted to manure treatment are quantified Additional Information: Impacts of plant production to humus content
  6. 6. LCA Impact Parameter Biomass cultivation (Pesticides, fertilizer, diesel consumption) Transport Running of plant, diffuse emissions Utilization of biogas, CHP Impacts to Manure efficiency Humus content
  7. 7. Result: LCA I Overview of 12 biogas plant models 900 700 Fossil comparator 500 300 g CO2,eq/kWhel 100 -100 Cultivation Transport and distribution (including storage of raw material) Diffuse emissions -300 -500 -700 Methane leakage in the CHP generator Externally used heat -900 -1,100 -1,300 Avoiding methane emissions from manure Net emissions
  8. 8. Key findings, GHG Avoided methane emissions due to manure treatment as most relevent effect Substitution of fossil heat second most influencing factor Biogas process is dominated by diffuse methane emissions; based on CHP operation The cultivation of energy crops is connected to emissions The more energy crops are used the higher CO2 emissions exist The difference between biogas plants in organic and conventional farms is determined highly through use of substrates Emissions associated with transport are of minor importance
  9. 9. Scenario: Methane emissions 15 % diffuse Methane emissions (before 1 %) 1100 900 700 Fossil comparator Cultivation g CO2,eq/kWhel 500 300 100 -100 Transport and distribution (including storage of raw material) Diffuse emissions and storage -300 -500 -700 Methane leakage in the CHP generator Externally used heat -900 -1100 Avoiding methane emissions from manure -1300 Net emissions Energy crops are located around the fossile comparator! Manure treatment plants mitigate GHG
  10. 10. Further environmental aspects Two comparisons of operation methods are analysed: Organic Farms with and without a biogas plant Biogas plants in organic and conventional farming Generalization: Whole Europe Individual situations are crucial (climate, soil quality, crop rotation, regime) => Generalization critical
  11. 11. Soil quality It has to be distinguished between crop cultivation and effect of digestate. Impacts of a biogas plant onto organic farm Differences in farms with and without livestock Catch crops are cultivated more often Increased N fixation, less N-leaching (in comparison to mulching), reduction of N2O-emissions Flexible utilization of fertilizer Humus balance, individual reconsideration, C-removal vs root growth Phytosanitary effects; Deaktivation of weed seeds, promotion of N-availability The influence onto soil quality is dominated through substrates and their cultivation . Biogas in organic in comparison to conventional farming More catch crops, less renewable resources Pesticides, mineral fertilizer
  12. 12. Food vs Feed Substrate Positive Effects Negative Effects Effects of biogas on food security in organic farming depends on the substrates and the use of the land associated with it: Area competition Soil quality Enery crops Catch crops Increased yield Higher protein content in plants Livestock production: competition Harvesting residues Increased yield Higher protein content in plants Livestock production: competition Manure Increased yield Higher protein content in plants
  13. 13. Water quality Organic farm with and without Biogas plant Catch crops, decreased N-leaching in comparison to mulching Manure, N-leaching can be increased; Dung, N-leaching reduced Disasters have high negative potential Organic vs conventional farm Correlation of regions with high density of animal husbandry, density of biogas and pollution of ground water with Nitrate Intensification of conventional farms can additionally lead to higher N-loads N often is a limiting factor vs higher N-inputs
  14. 14. Biodiversity Organic Farming Correlation with Biodiversity With soil fertility, with N-charge (digestate) Expension of cultivation and harvest period Seeds of foreign kinds are deactivated Negative impacts of over-fertilization, eutrophication Erosion of Biomass (Manure, straw, harvest residues) has complex impacts Losses of habitats Yield increase Better control (especially N) Cultivation of energy crops Higher competition and pressure on agricultural areas Reduction of closure sites LUC Impact onto biodiversity dependend on plant type
  15. 15. Independence of fossile energy Biogas can be used in many ways Electricity Heating and cooling Heating of buildings Processes (Breeding of piglets, cooling dairy products,….) Drying Selling Fuels As biomethan, as a substitute for natural gas As biogas directly Biogas can hence lead to a substitution and independence of fossile energy
  16. 16. Socioeconomic effects Few differences btw organic and conventional biogas General impacts of operating with biogas Social effects Development of rural areas Creating a network, exchange of information Cooperation Acceptance Negative: Odor, transport, noise, fear Employment opportunities 45.000 jobs in biogas sector (source: FVBG, Germany), 10.000 farms App. 12 people per Mwel that is installed Revenue Investment biomass electricity (solid & gaseous): 1,5 Mia € in 2012 Turnover biomass (Electricity and heat, without fuels): 6,8 Mia. € in 2012 (AGEEStat); (Biogas kanns: 6 Mia. €, German sources) Regional turnovers increase
  17. 17. Summary I GHG balance: Biogas plants in organic farming can improve the LCA of a farm and further produce renewable energies Manure treatement is a crucial part Utilization of heat Avoid methane emissions Limit cultivation of energy crops
  18. 18. Summary II Soil fertility can be improved through a biogas plant. Production of organic biogas does not (or in a reduced way) mean a competition to food production Water quality: Reduced N-leaching Biodiversity: Biogas can expand crop rotation cycle Biogas offers the possibility to become independent of fossile resources Biogas is socio economically feasible Acceptance, (local) employment opportunities, revenues
  19. 19. Thank you for your attention! Frank Hofmann Ecofys Germany GmbH