Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions of Fuel Ethanol Produced from U.S. Midwest Corn

Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions

“…Until very recently, researchers believed that using ethanol in motor vehicles to replace petroleum-based gasoline caused net increases in GHG emissions and fossil energy use (Wang et al 1997). The Center for Transportation Research (CTR) at Argonne National Laboratory (Argonne) has been conducting analyses of fuel-cycle energy and emissions impacts of various alternative transportation fuels, including corn ethanol.…”

“…The Center for Transportation Research (CTR) at Argonne National Laboratory (Argonne) has been conducting analyses of fuel-cycle energy and emissions impacts of various alternative transportation fuels, including corn ethanol. A recent CTR analysis found that prior studies indicating increases in GHG emissions resulting from the use of corn ethanol were no longer accurate because these studies employed relatively old data (Wang et al 1997). The CTR research revealed that, when more current data are employed, estimates of these emissions actually decrease.…”

“…We documented our upstream assumptions regarding corn-based ethanol in a separate report (Wang et al 1997). In that report we estimated emissions and energy impacts of ethanol produced from U.S. Midwest corn.…”

“…Past studies showed large variations in N 2 O emissions from these sources. On the basis of a detailed review of studies for U.S. cornfields, Wang et al (1997) concluded that about 1.5% of the nitrogen in nitrogen fertilizer applied to cornfields is released as nitrogen in N 2 O emissions to the atmosphere. We adopted this value for our study.…”

“…We collected information regarding recent trends in plant energy use from ethanol plant designers and operators in order to update estimates of total energy use. In a previous report (Wang et al 1997), we estimated energy use rates of 41,400 Btu/gal of ethanol produced for a dry milling ethanol plant and 40,300 Btu/gal of ethanol produced for a wet milling plant. For near-term future ethanol plants (around 2005), given information obtained from designers and operators, we estimated that continuing improvements will result in an energy use rate of 36,900 Btu/gal for new dry milling plants and 34,000 Btu/gal for new wet milling plants.…”