Measures to reduce GHG emissions in the Biomethane supply-chain

Transcription

1 Measures to reduce GHG emissions in the Biomethane supply-chain William Mezzullo Paris - March 2013 Presentation Overview Reducing GHG emissions from biomethane production Overview of biomethane production chain Emissions at stages of biomethane production Recommendations to reduce GHG emissions Sustainability Criteria updates from EC ILUC & double accounting

2 Biomethane production chain Feedstock Transport Storage AD Process Biomethane Inputs/Outputs/Emissions Diesel NPK Fertiliser Other farming inputs Other consumables Diesel Other consumables Diesel Other consumables Diesel - mat. handling Electricity onsite Heat onsite Other consumables Electricity Heat (depends) Water (depends) Other consumables Feedstock Transport Storage AD Process Biomethane GHG emissions (CO 2, N 2 O for example) Diesel CO 2 Diesel CO 2 GHG emissions (electricity from grid, CH 4 slip, diesel CO 2 ) CH4 slip, electricity from grid

3 Lifecycle Greenhouse Gas Emissions (Percentage) 80 Percentage of Total Emissions Cul va on & Harves ng 40 Transport & Distribu on Produc on of Biogas 30 Biomethane Upgrade Biomethane Injec on Silage Grass Whole Crop Maize Organic Whole Crop Maize Whole Crop Wheat Sugar Beet Wet Manure Dry Manure Feedstock GHG emissions - Feedstock Feedstock Feedstock crop production can lead to high GHG emissions if artificial NPK are used. According to Biograce indirect emissions of fertiliser are: Nitrogen = 5.88kgCO2/kg nutrient Phosphate = 1.1kgCO2/kg nutrient Potassium = 0.58kgCO2/kg nutrient Emissions from artificial NPK can be avoided through the use of digestate (around 100% of N, 100% P and 80% K can be returned to land) However direct and indirect N2O emissions are released when N from digestate is applied to land this can contribute to over 50% of the CO2 emissions from feedstock production

4 GHG emissions - Feedstock Feedstock Emissions to produce 1 tonne of maize using chemical fer liser (kgco 2 eq/tmaize) Seeds 0% K emissions 3% P emissions 1% Pes cides 0% Diesel 9% Direct N2O 34% N emissions 42% Indirect N2O 11% GHG emissions - Feedstock Feedstock Emissions to produce 1 tonne of maize using chemical fer liser (kgco 2 eq/tmaize) Seeds 0% K emissions 3% P emissions 1% N emissions 42% Pes cides 0% Diesel 9% Direct N2O 34% Indirect N2O 11% Using digestate will avoid up to 50% of GHG emissions However soil N2O emissions are still present These can be reduced via nitrogen inhibitors

5 Reccommendations Feedstock Minimise the use of artificial NPK through careful nutrient recycling Year 1 crops should also avoid artificial NPK through use of muck/manures Nitrogen inhibitors should be used: These can be mixed with liquid digestate or manures Inhibitor delays transformation of ammonium into nitrate (better soil retention) Reduces N wash out and leaching N2O emissions can be reduced by 60-84% 1 1 Urs Schmidhalter, Reinhold Manhart, Kurt Heil, Martine Schraml, Sabine v.tucher, FreisingFertilisation of Maize with Liquid Manure and Fermentation Residue The influence of a nitrification inhibitor on growth, yield and the environment. AD Process GHG emissions AD Process The AD process can contribute up to 10-30% of total GHG emissions for biomethane production This can be significantly more with open digestate storage tanks Plant uptime is critical to reduce GHG emissions (kgco 2 /kwh). Methane slip around the plant (due to age of the plant for example) can have a significant impact of GHG emissions.

6 Recommendations AD Process AD Process Ensure all digestate tanks and covered and air tight sealed little financial incentive High uptime will reduce the requirement for importing grid-electricity (and fossil heat to maintain digester temperature for example) financial incentive Ensure flare is installed onsite at all times - little financial incentive Perform regular checks for methane leaks around the plant - potentially financial incentive Case Study Sweden AD Process AD Process 2007 Voluntary Agreement initiated in Sweden to minimise methane emissions from AD plants. Methane leak detection carried out every 3 years Methane measuring methods follow EN ISO 25139:2011 Standards Upgrading plant methane leakage is measured separately Methane from AD plants varied from 0.1% to 6%

7 Biomethane GHG emissions - Biomethane production Energy requirements for biogas upgrading process vary depending on the technology selection: Membrane separation uses kWh electricity /m 3 raw biogas Chemical Absorption uses up to 0.6 kwh heat /m 3 raw biogas The energy requirements can be neglected or minimised significantly if they come from a biogas CHP onsite. The largest GHG emission contribution however is methane slip from the upgrading process. Biomethane GHG emissions methane slip BiogasPartner - Biogas Grid Injection in Germany and Europe (Fraunhofer Umsicht (2009) IEA Task 37 Biogas Upgrading Technologies Developments & Initiatives

8 Recommendations reducing methane slip Biomethane For every 1% methane slip this will add around 20 kgco 2eq /MWh biomethane : For a typical AD plant with 100kgCO2/MWh this can add another 20% (per 1% rise) EU 60% GHG target = 125kgCO2eq/MWh of biomethane Methane from offgas can be removed via: Direct combustion of offgas (only possible by adding fossil gas or biogas as the CV will be too low to combust) Re-directing offgas into CHP (similar issue to above) Oxidising the offgas (Regenerative Thermal Oxidiser) works at lower methane concentration (2-3%) Selecting upgrading technologies with low methane slip will not solve the issue. Case Studies methane slip reporting Biomethane Sweden: Voluntary scheme of methane slip reporting (as mentioned before) 0.1% up to 12% for Water Scrubber Germany: Obligatory 0.2% methane slip NL & UK: No obligation however this is covered to some extent by Country Sustainability Criteria (GHG reduction)

9 Updates from EC Biofuels using crops ooct 2012 EC published a proposal to reduce the production of biofuels from starch/sugar/oil crops. oproposal to limit biofuels from some crops to no more than 5%. obiofuels from some feedstocks (algae, MSW etc) shall be considered to have 4 times the energy content. obiofuels from other wastes (animal fats, non-food cellulosic material) shall count twice oproposal also sees an increased reduction in GHG emissions by 60% with immediate effect Updates from EC ILUC oec has proposed including ILUC factors in the lifecycle GHG calculation for biofuels. othe proposal will be for biofuel producers to report only and not linked to incentives. 43 kgco 2 /MWh 47 kgco 2 /MWh 198 kgco 2 /MWh

10 Dr. William Mezzullo Thank you