Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis versus System-wide Accounting
AbstractLife 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 impactsâ€”including land use changesâ€”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.
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Bibliographic InfoPaper provided by Center for Agricultural and Rural Development (CARD) at Iowa State University in its series Center for Agricultural and Rural Development (CARD) Publications with number 08-wp461.
Date of creation: Feb 2008
Date of revision:
biofuels; corn ethanol; greenhouse gas; life cycle analysis; system-wide accounting.;
Other versions of this item:
- Feng, Hongli & Rubin, Ofir D. & Babcock, Bruce A., 2008. "Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis versus System-wide Accounting," 2008 Annual Meeting, July 27-29, 2008, Orlando, Florida 6503, American Agricultural Economics Association (New Name 2008: Agricultural and Applied Economics Association).
- Feng, Hongli & Rubin, Ofir & Babcock, Bruce A., 2008. "Greenhouse Gas Impacts of Ethanol from Iowa Corn: Life Cycle Analysis Versus System-Wide Accounting," Staff General Research Papers 12871, Iowa State University, Department of Economics.
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
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- David A. Hennessy, 2004. "On Monoculture and the Structure of Crop Rotations," Center for Agricultural and Rural Development (CARD) Publications 04-wp369, Center for Agricultural and Rural Development (CARD) at Iowa State University.
- Hennessy, David A., 2004. "On Monoculture and the Structure of Crop Rotations," Staff General Research Papers 12004, Iowa State University, Department of Economics.
- Baker, Mindy L. & Babcock, Bruce A., 2008. "Value maximization from corn fractionation: feed, greenhouse gas reductions, and cointegration of ethanol and livestock," Transition to a Bio Economy Conferences, Integration of Agricultural and Energy Systems Conference, February 12-13, 2008, Atlanta, Georgia 48714, Farm Foundation.
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