It takes almost 70,000 Btu to produce ONE GALLON of ETHANOL and its associated byproducts.

1. ENERGY INPUTS TO ETHANOL 68% Ethanol Conversion (dry milling ethanol plant) 47,116 Btu • It takes almost 70,000 Btu to produce ONE GALLON of ETHANOL and its associated byproducts. • Only 17% of the required energy comes from gasoline or diesel; other energy inputs can contribute to produce this gasoline substitute • The single greatest requirement is the heat energy needed for distillation; Ethanol plants in Wisconsin typically use natural gas. Ethanol Conversion: An ethanol plant requires a tremendous amount of heat energy for fermentation, distillation and dehydration, plus some electricity for grinding grain and running motors throughout the plant. Natural gas provides about 90% of the energy used in a typical dry milling ethanol plant. A more efficient and more renewable process: The predominant non-renewable heat sources could be replaced with biomass/biogas combustion, or solar thermal energy. Or, more waste heat could simply be recovered. Economics of this would depend on the scale of production, and coordination with other industrial processes. Corn Production: Sustainable Farming for Sustainable Fuel Raising the corn accounts for more than 1/4 of the total primary energy required for ethanol. A lot of natural gas is used to produce nitrogen fertilizers. Wisconsin corn growers use about 9 gal of diesel per acre. Renewable resources like manure & biodiesel could offset these inputs. Technologies for cellulosic ethanol production could utilize the stover, or other fibrous crops such as switchgrass. 27% Corn Production 18,875 Btu Transportation: Energy for transportation is minimal. Corn ethanol plants in Wisconsin source most of the grain from within 60 miles of the plant, and are located on a rail line for exporting the ethanol. 5% Transport