Fuel ethanol cannot alleviate US dependence on petroleum

July 1, 2005

A new study of the carbon dioxide emissions, cropland area requirements, and other environmental consequences of growing corn and sugarcane to produce fuel ethanol indicates that the "direct and indirect environmental impacts of growing, harvesting, and converting biomass to ethanol far exceed any value in developing this energy resource on a large scale." The study, published in the July 2005 issue of BioScience, the journal of the American Institute of Biological Sciences (AIBS), uses the "ecological footprint" concept to assess needs for ethanol production from sugarcane, now widespread in Brazil, and from corn, which is increasing in the United States.

In Brazil, ethanol from fermentation of sugarcane is used pure or blended with gasoline to yield gasohol, which contains 24 percent ethanol. In the United States, ethanol made from corn, production of which is heavily subsidized, is used in an 85 percent ethanol mixture called E85. In 2003, ethanol-blended gasoline accounted for more than 10 per cent of gasoline sales in the United States.

The authors of the study assessed the energy required to produce the crops and to manufacture and distribute the resulting fuels. In the United States, ethanol yielded only about 10 percent more energy than was required to produce it; in Brazil, where a different process is used, ethanol yielded 3.7 times more energy than was used to produce it. The researchers, Marcelo E. Dias de Oliveira, Burton E. Vaughan, and Edward J. Rykiel, Jr., also weighed effects of fuel ethanol use on carbon dioxide emissions, soil erosion, loss of biodiversity, and water and air pollution, assuming vehicles representative of each country. Specialized software was used to analyze the sensitivity of the conclusions to diverse assumptions in the analysis.

Dias de Oliveira and colleagues then looked at some consequences of moving to greater fuel ethanol use. The results were unfavorable to fuel ethanol in either country. In Brazil, reducing the rate of deforestation seemed likely to be more effective for taking carbon dioxide out of the atmosphere. In the United States, reliance on ethanol to fuel the automobile fleet would require enormous, unachievable areas of corn agriculture, and the environmental impacts would outweigh its benefits.

"Ethanol cannot alleviate the United States' dependence on petroleum," Dias de Oliveira and colleagues conclude. They argue for the development of multiple alternatives to fossil fuels. Ethanol may, however, still be useful in regions or cities with critical pollution problems, they write, and to make use of agricultural wastes.

Source: American Institute of Biological Sciences

Explore further: China plans nationwide ethanol use by 2020

Related Stories

China plans nationwide ethanol use by 2020

September 13, 2017

China plans to expand use of ethanol in gasoline nationwide by 2020 to curb smog and fossil fuel demand, the government said Wednesday, joining United States, Brazil and other nations that use blended fuel.

Firebricks offer low-cost storage for carbon-free energy

September 6, 2017

Firebricks, designed to withstand high heat, have been part of our technological arsenal for at least three millennia, since the era of the Hittites. Now, a proposal from MIT researchers shows this ancient invention could ...

LSU professors work to improve efficiency of ethanol fuel

August 13, 2007

Lowering fuel emission levels is a topic facing constant scrutiny by the global public. Rising gas costs, environmental concerns and conflicts in oil-producing areas have made consumers, corporations and researchers more ...

Recommended for you

Mathematics predicts a sixth mass extinction by 2100

September 20, 2017

In the past 540 million years, the Earth has endured five mass extinction events, each involving processes that upended the normal cycling of carbon through the atmosphere and oceans. These globally fatal perturbations in ...

New hermit crab uses live coral as its home

September 20, 2017

A new hermit crab species can live in a walking coral's cavity in a reciprocal relationship, replacing the usual marine worm partner, according to a study published September 20, 2017 in the open-access journal PLOS ONE by ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.