GHG Mitigation Potential of Biofuels in Canada Stephanie Bailey Stamler Resource Efficient Agricultural Production (REAP)-Canada Toronto, Ontario sbailey@
GHG s-why They re Important Include water vapour, ozone, carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O). Occur naturally in the atmosphere and trap energy from the sun. Without them, Earth s temperature would be 33 C lower. Human activities are increasing GHG s.
What is a GHG Offset? A reduction or avoidance in GHG emissions in one place in order to offset emissions somewhere else. GHG s differ in their global warming potential - their ability to absorb heat in the atmosphere. 1 Greenhouse Gas 100 yr-gwp Carbon Dioxide-CO 2 Methane-CH 4 23 Nitrous Oxide-N 2 O 296 Expressed in CO 2 equivalents
Biofuel GHG Offsets Basics GHG offsets are a function of 2 main factors: The total amount of renewable energy (GJ) produced/ha (solar energy collected in the field less energy lost going through the biofuel conversion process) The amount of fossil energy (GJ) used in the production of the feedstock/ha The amount of fossil energy used to convert the raw feedstock to a processed biofuel form
Comparing Biofuels as Offset Factors to Consider: Strategies Net GHG savings by replacing a fossil fuel with a a biofuel option (kg CO 2 e/gj). Efficiency of the offset (%). The cost of incentives or subsidies for each unit energy produced ($/GJ). Cost required to offset 1 tonne of CO 2 e ($/tonne).
N 2 O Emissions Problem Canadian models estimating GHG for biofuels from agriculture crops do not include N 2 O emissions. Annual crops take up less than 50% of applied nitrogen (N) fertilizer. Remaining N results in nitrate losses to water or gaseous N to the atmosphere. Need to examine N 2 O emissions from annual grains and oilseeds used for biofuels.
N 2 O Emissions from Crop Production in Canada 3.5 3 3 1500 kg N2O-N ha -1 y -1 2.5 2 1.5 1 0.5 1218 kg CO 2 eq ha - 1 y -1 1.5 1.2 0.5 0.3 1200 900 600 300 kg CO2eq ha -1 y -1 0 Corn Soybeans Canola Switchgrass Switchgrass (fertilized) (unfertilized) 0 e.g. Corn: 3 kg N 2 O-N x 44/28 x 310 (CO 2 forcing value for N 2 O) = 1461 kg CO2eq/ha Samson et al 2007
Biofuel Options Examined Sector Traditional Fuel Alternative Fuel Transportation Gasoline Ethanol Diesel Biodiesel Electrical Power Wind energy Coal Straw pellets Natural gas Biogas Heating Coal Natural gas LNG Switchgrass/Wood pellets LNG-liquefied natural gas
Relative Carbon Intensity of Various Fuel Sources GHG Emissions (Kg CO2/GJ) 100 90 80 70 60 50 40 30 20 10 0 93.1 87.9** Coal Heating Oil 73.8 Liquefied Natural Gas 57.6 Natural Gas 13.1 Wood Pellets (BG) 8.2 SG Pellets (BG) *Based on GHGenius 3.9xls Natural Resources Canada, Samson et al., 2007 **Based on typical Canadian oil mix of 48% domestic and 52% international
Transportation Sector-GHG Offsets Fossil Fuel kg CO 2 e/gj Renewable Fuel kg CO 2 e/gj Net offset (%) Gasoline Diesel 99.6 95.5 Corn ethanol Cellulosic ethanol Soybean biodiesel Canola biodiesel 62.0 23.4 * 36.4 28.8 * Does not include GHG emissions associated with N 2 O from cultivation 21 76 50 58 Samson et al., 2007
Electrical Power-GHG Offsets Fossil Fuel kg CO 2 e/gj Coal 298.9 Natural gas 121.7 Wind Straw Pellets Biopower (manure) * Wind Renewable Fuel kg CO 2 e/gj 5.6 18.9 39.4 5.6 Net offset (%) 98 94 87 95 Straw Pellets 18.9 84 Biopower (manure) * 39.4 68 Does not include GHG emission reductions from manure through biogas treatment Samson et al. 2007 Samson et al., 2007
Heat Generation-GHG Offsets Coal LNG Fossil Fuel Natural gas kg CO 2 e/gj 93.1 87.9 57.6 Renewable Fuel Switchgrass pellets Switchgrass pellets Switchgrass pellets kg CO 2 e/gj 8.2 8.2 8.2 Net offset (%) 91 89 86 Samson et al., 2007
100 80 60 40 20 0 Offset Efficiency of Biofuel Options Biodiesel Ethanol Straw pellets Wind Biopower (manure) Wind Biopower (manure) Straw pellets Switchgrass pellets Switchgrass pellets Switchgrass pellets Diesel Gas Coal NG Coal LNG NG Transport Electrical power Heating NG-natural gas; LNG-liquefied natural gas Samson et al. 2007 Offset Efficiency (%)
GHG Offsets From Ontario Farmland Using Biofuels Total GHG emission offsets (KgCO2e/ha) 14000 12000 10000 8000 6000 4000 2000 0 905 Soybean biodiesel for conventional diesel 1,492 Grain corn ethanol for gasoline 5,583 SG cellulosic ethanol for gasoline 7,617 SG pellets for natural gas 10,103 SG pellets for LNG 12,294 SG pellets for heating oil 13,098 SG pellets for coal SG=Switchgrass; LNG=Liquefied Natural Gas
Summary Biofuel GHG offsets are directly linked to Offset efficiency of the biofuel (GJ) Energy produced (GJ) per ha of biofuel crop Biofuel Option Offset efficiency Output (GJ/ha) Overall efficiency Switchgrass pellets High High Switchgrass ethanol Moderate to high Moderate Corn ethanol Low Moderate Soybean biodiesel Moderate Low
Thank You! WWW.REAP-CANADA.COM REAP-Canada s Biomass Energy Program Sponsored by