Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis Versus System-Wide Accounting

Hongli Feng, Ofir Rubin and Bruce Babcock

Staff General Research Papers Archive from Iowa State University, Department of Economics

Abstract: Life cycle analysis (LCA) is the standard approach used to evaluate the greenhouse gas (GHG) benefits of biofuels. However, it is increasingly recognized that LCA results do not account for some impacts-including land use changes-that have important implications on GHGs. Thus, an alternative accounting system that goes beyond LCA is needed. In this paper, we contribute to the literature by laying out the basics of a system-wide accounting (SWA) method that takes into account all potential changes in GHGs resulting from biofuel expansion. We applied both LCA and SWA to assess the GHG impacts of ethanol based on Iowa corn. Growing corn in rotation with soybeans generated 35% less GHG emissions than growing corn after corn. Based on average corn production, ethanol's GHG benefits were lower in 2007 than in 2006 because of an increase in continuous corn in 2007. When only additional corn was considered, ethanol emitted about 22% less GHGs than gasoline. Results from SWA varied with the choice of baseline and the definition of geographical boundaries. Using 2006 as a baseline and 2007 as a scenario, corn ethanol's benefits were about 20% of the emissions of gasoline. If we expand geographical limits beyond Iowa, but assume the same emission rates for soybean production and land use changes as those in Iowa, then corn ethanol generated more GHG emissions than gasoline. These results highlight the importance of boundary definition for both LCA and SWA.

Keywords: biofuels; corn ethanol; greenhouse gas; life cycle analysis; system-wide accounting (search for similar items in EconPapers)
Date: 2008-02-01
New Economics Papers: this item is included in nep-agr, nep-ene and nep-env
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Citations: View citations in EconPapers (5)

Published in Biomass and Bioenergy, June 2010, vol. 34 no. 6, pp. 912-921

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Related works:
Working Paper: Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis versus System-wide Accounting (2008)
Working Paper: Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis versus System-wide Accounting (2008)
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Persistent link: https://EconPapers.repec.org/RePEc:isu:genres:12871

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