Authors
Title
Replacing gasoline with corn ethanol results in significant environmental problem-shifting
In
Environ. Sci. Technol.
Volume
46
Pages
3671–3678
Publisher
ACS
Year
2012
Publisher's URL
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Abstract
Previous studies on the life-cycle environmental impacts of corn
ethanol and gasoline focused almost exclusively on energy balance and
greenhouse gas (GHG) emissions and largely overlooked the influence of
regional differences in agricultural practices. This study compares the
environmental impact of gasoline and E85 taking into consideration 12
different environmental impacts and regional differences among 19 corngrowing
states. Results show that E85 does not outperform gasoline when a
wide spectrum of impacts is considered. If the impacts are aggregated using
weights developed by the National Institute of Standards and Technology
(NIST), overall, E85 generates approximately 6% to 108% (23% on average)
greater impact compared with gasoline, depending on where corn is produced,
primarily because corn production induces significant eutrophication impacts
and requires intensive irrigation. If GHG emissions from the indirect land use
changes are considered, the differences increase to between 16% and 118% (33% on average). Our study indicates that replacing
gasoline with corn ethanol may only result in shifting the net environmental impacts primarily toward increased eutrophication
and greater water scarcity. These results suggest that the environmental criteria used in the Energy Independence and Security
Act (EISA) be re-evaluated to include additional categories of environmental impact beyond GHG emissions.
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