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Environmental Sustainability of Biofuel Crops

Environmental Sustainability of Biofuel Crops. Bill Chism (chism.bill@epa.gov) David Widawsky (widawsky.david@epa.gov) Office of Policy, Economics and Innovation US Environmental Protection Agency. Photos from USDA, ARS, Image Gallery. Physical Factors Climate and Topography.

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Environmental Sustainability of Biofuel Crops

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  1. Environmental Sustainability of Biofuel Crops Bill Chism (chism.bill@epa.gov) David Widawsky (widawsky.david@epa.gov) Office of Policy, Economics and Innovation US Environmental Protection Agency Photos from USDA, ARS, Image Gallery

  2. Physical Factors Climate and Topography Crop Production Inputs Outputs Assets Crop Production Generalized Diagram Environmental Sustainability of Biofuel Crops

  3. Inputs and Outputs of Biofuel Crop Production Crop Energy Food Compounds Physical Factors Climate Temperature Rainfall Soil Characteristics Topography Slope Distance to water Energy - Sun - Petrochemical (fuel, fertilizer, manufacturing, etc.) Air Emissions Nitrogen (NO2 -) Carbon (tillage) Particulates Atmospheric Carbon Crop Production Starch – corn Oil Seed – soybean Perennial Grass – Switchgrass Sugar Crop – Sugarcane Woody Biomass - Poplar Agric Practices Tillage Planting Crop & Cultivar Pest Control Secondary Products (Animal Feed) Distillers Dry Grain Glycerol Lignin Water Rainfall (nitrogen) Irrigation Leaching & Runoff Nitrogen (NO3 -) Phosphorus (H2 PO4 ) Soil Assets Soil Organic Matter Carbon and Minerals Water – filter & storage Wildlife Ecological Services Land Use / Consumption Nutrients Fertilizer Soil & Crop Residue Water Recharge (pos) Evaporation (neg) Environmental Sustainability of Biofuel Crops

  4. Starch (Corn) For Ethanol – Outputs►low net energy; serious sustainability issues◄ Many Alternative Uses Energy, Feed, Food, Sweetener, etc. Distillers Dry Grain for Animal Feed Waste to fertilizer Heat Methane Net Energy 1.3 to 1.7 : 1 Corn Production Outputs GHG Reduction 22% < gasoline Sustainability Issues Runoff & Drain Tiles Erosion N and P Pesticides Assets Energy and GHG Reduction are Well to Wheel Optimized, CA Low Carbon Fuel Std Environmental Sustainability of Biofuel Crops

  5. Oil Seed Crop (Soybean) For Biodiesel – Outputs►moderate net energy; sustainability issues; lower financial returns◄ Many Alternative Uses Energy, Feed, Food, Oil, etc. Soybean Meal for Animal Feed Waste to fertilizer Heat Methane Net Energy 3.2 : 1 Soybean Production Outputs GHG Reduction 68% < diesel Sustainability Issues Runoff & Drain Tiles Erosion Pesticides Assets Energy and GHG Reduction are Well to Wheel Optimized Environmental Sustainability of Biofuel Crops

  6. Cellulosic Ethanol (Switchgrass) – Outputs►higher net energy; sustainability advantages; technical/financial barriers◄ Net Energy 4.4 to 6.1 : 1 Alternative Uses Less Marketable CRP, Wildlife Habitat Develop New Biofuel Production System – acid or enzyme? Switchgrass Production Outputs GHG Reduction 91% < gasoline Sustainability Issues ☼Lowest Runoff ☼Lowest Erosion ☼Low Fertilizer Use (N and P) ☼Lowest pesticide Use Assets Energy and GHG Reduction are Well to Wheel Optimized Environmental Sustainability of Biofuel Crops

  7. Changing Crop Rotations► changing rotation can increase runoff and reduce average yields◄ Corn Fertilization (U.S.) N = 97 % at 131 lb/acre P = 81 % at 57 lb/acre Corn Corn Corn Fertilization (U.S.) N = 97 % at 131 lb/acre P = 81 % at 57 lb/acre Sustainability Issues (Minn.) NO3-N in runoff = 45.5 lb/acre Drain tile flow = 3.1 t water/acre 2 Year Continuous Corn 12% lower corn yield Soybean Soybean Fertilization (U.S.) N = 15 % at 24 lb/acre P = 24 % at 48 lb/acre 2 Year Crop Rotation 18% higher soybean yield 12% higher corn yield Sustainability Issues (Minn.) NO3-N in runoff = 40 lb/acre Drain tile flow = 2 t water/acre Environmental Sustainability of Biofuel Crops

  8. Environmental Impact of Converting 14 million acres of soybean to corn Change in Runoff (%) Tons of Runoff Source: L. Marshall. 2007. The Thirst For Corn. WRI Environmental Sustainability of Biofuel Crops

  9. Conversion System Affects Sustainability of Biomass Production • Influence of Conversion Platforms on Biomass Production • Single crop systems • “Omnivorous” systems • Timing of biomass utilization • Biomass storage (quality, quantity) • All of these can affect: • Water, air, soil effects • Wildlife habitat • Other ecological services Environmental Sustainability of Biofuel Crops

  10. Sustainability Characteristics* of Mitigation Options * Other categories could be added: nitrous oxides, soil carbon, wildlife, etc. Environmental Sustainability of Biofuel Crops

  11. Research Information Gaps • Life Cycle Analysis – Agricultural Inputs • Accounting methods • Values of Secondary Products • Comparison Between Single-year and Multi-year Crops • Impact of Biofuel Processing Method – “omnivorous” processing system versus crop specific system • Biofuel “Green” Index – Well-to-Crop Rating System • Develop crop sustainability data • Methods for comparing different models • Sustainability - Land, Crop Residues, and Water * • Land Use Change * • Crop Production Practices * * Federal Biofuels Posture Plan Workshop Feedstock Session Notes Environmental Sustainability of Biofuel Crops

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