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Politics : PRESIDENT GEORGE W. BUSH -- Ignore unavailable to you. Want to Upgrade?

To: SecularBull who wrote (149707)	5/30/2001 7:00:22 PM
From: ColtonGang	Read Replies (2) \| Respond to of 769670

Here's your answer.............Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions of Fuel Ethanol Produced from U.S. Midwest Corn by Michael Wang, Christopher Saricks, and May Wu Argonne National Laboratory Transportation Technology R&D Center 9700 S. Cass Avenue Argonne, IL 60439 Document Type: Sponsor Report (58 pages) Sponsor: Illinois Department of Commerce and Community Affairs Publication Date: December 19, 1997 Contact for Full Report: Michael Wang, 630/252-2819 EXECUTIVE SUMMARY This study has been undertaken at the request of the Illinois Department of Commerce and Community Affairs (DCCA) on the twin premises that (1) data and information essential to an informed choice about the corn-to-ethanol cycle are in need of updating, thanks to scientific and technological advances in both corn farming and ethanol production; and (2) generalized national estimates of energy intensities and greenhouse gas (GHG) production are of less relevance than estimates based specifically on activities and practices in the principal domestic corn production and milling region -- the upper Midwest. Argonne National Laboratory contracted with DCCA to apply Argonne's Greenhouse gas, Regulated Emissions and Energy in Transportation (GREET) full-fuel-cycle analysis model with updated information appropriate to corn operations in America's heartland in an effort to examine the role of corn-feedstock ethanol with respect to GHG emissions given present and near future production technology and practice. Information about these technologies and practices was obtained from a panel of outside experts consisting of representatives of the U.S. Department of Agriculture, midwestern universities with expertise in corn production and soil emissions, and acknowledged authorities in the field of ethanol plant engineering, design, and operations. A draft version of this report was peer reviewed by these contributors, and their comments have been incorporated. Among key findings is that, for all cases examined on a mass emission per travel mile basis, the corn-to-ethanol fuel cycle for Midwest-produced ethanol utilized as both E85 and E10 outperforms that of conventional (current) and of reformulated (future) gasoline with respect to energy use and greenhouse gas production. In many cases, the superiority of the energy and GHG result is quite pronounced (i.e., well outside the range of model "noise"). An important facet of this work has been the conduct of sensitivity analyses using GREET, which could enable development of a ranking of the factors in the corn-to-ethanol cycle that are most important with respect to GHG generation. This could assure that efforts to reduce that generation are more effectively targeted. The intent and scope of this study was limited to revision and upgrading of the GREET model to address corn farming and ethanol production in four Midwest states (Illinois, Iowa, Nebraska, and Minnesota) that collectively account for (1) about half of the total domestic corn harvest in a given year, (2) about 90% of the U.S. total 1.58 billion gallon ethanol annual production capacity, and (3) about 95% of total domestic ethanol production. That is, while the model still covers all alternative fuels and five criteria pollutants, no efforts have been made in this project to update input data on other fuels and the criteria pollutants. A weighted energy intensity for corn farming of less than 20,000 Btu/bushel was calculated for the four-state analysis, a value that should be considered conservative. The study also estimated (or re-estimated) energy requirements for fertilizer and pesticide manufacture, transportation to farms, and field application; transportation of harvested corn to ethanol plants; nitrous oxide emissions from cultivated cornfields; energy use and greenhouse gas (GHG) emissions of ethanol production in current average and future technology wet and dry mills; and end-use fuel efficiency and GHG emissions from ethanol-fueled vehicles. Because cogeneration is present in virtually all wet mills, recently built wet milling plants have total process energy requirements comparable to those for dry mills (i.e., slightly over 40,000 Btu/gallon). Ongoing and future efficiency improvements from retrofits and advanced new plant designs should bring average process energy requirements well under 35,000 Btu/gallon for all mills. Our base case analysis estimates energy use and emissions for a present situation that includes technologies already in place and for a future situation in which technologies, especially ethanol production technologies, are expected to improve. The future case is to be applied for year 2005. Under the base cases, energy use and emissions are calculated for cars and light-duty trucks using E85 (85% ethanol and 15% gasoline by volume) and E10 (10% ethanol and 90% gasoline by volume). Baseline gasoline vehicles are fueled with conventional gasoline under the current base case, and with reformulated gasoline under the future base case. We also designed various sensitivity analysis cases to test the importance of key parameters in determining fuel-cycle energy use and GHG emissions. These were conducted for passenger cars for both current and future cases, but not for light-duty trucks as the relative changes in energy use and emissions between passenger cars and light-duty trucks are similar. Co-product energy use attribution remains the single key factor in estimating ethanol's relative benefits because this value can range from 0 to 50%, depending on the attribution method chosen. In general, wet mills produce a broader slate of high value end products which would be economically justifiable even if ethanol were not being produced, but the same cannot be said of dry mills, whose only other product for which an established market exists is distillers dried grain solids. If dry mills are not economically sustainable absent ethanol production, it could be argued that no co-product energy use attribution is warranted for them. GHG reductions (but not energy use) appear surprisingly sensitive to the value chosen for combined soil and leached N-fertilizer conversion to nitrous oxide, which falls in the range 0-2%. This narrow range of nitrous oxide emissions produces a range of near 20% in projected GHG savings for both present and future gasoline comparisons, the highest sensitivity ratio (approximately 1:4) within the value range for any variable explored. Meanwhile, the fuel cycle GHG production for use of E10 blend is 2-3% less than that of the corresponding gasoline. Fuel cycle energy and GHG savings profiles for present and future light duty trucks operating on E85 and E10 match those for automobiles. Although it is important to remember that our analysis has relied on the judgment of our panel of outside experts that near-term increases in corn-based ethanol demand can easily be accommodated by planting on land that has historically been devoted to growing corn and soybeans, we have concluded that, at least for the four states that we examined, use of corn-based ethanol achieves net energy savings and greenhouse gas emissions reductions in all blended fuel forms.