Preliminary EPA calculations showed that replacing gasoline with corn-based ethanol reduces greenhouse gas emissions by 61 percent, Recharge News reports.
However, after adding indirect land use effects to its life-cycle estimates, the EPA found that ethanol only reduced greenhouse gas emissions by 16 percent.
The estimates came as part of an EPA effort to draw up rules for the Energy Independence and Security Act of 2007 (EISA).
The act requires the EPA to develop rules to stimulate the introduction of biofuels that reduce transport sector greenhouse gas emissions.
Renewable fuel production facilities built following the passage of EISA need to provide a 20 percent reduction in life-cycle emissions, according to the EPA.
For ethanol, the EPA life-cycle emissions estimates cover the production and distribution of fuel and feedstock as well as the distribution and use of finished fuel by consumers.
The estimates come in the context of concerns by the Obama administration that the increase in ethanol-driven corn production in the United States is leading farmers in developing countries to plant other grains, resulting in the destruction of forests in favour of new farmland.
The US biofuels industry claims, on the other hand, that the actions of farmers in other countries shouldn’t affect the availability of ethanol in the Unites States.
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