Fuel ethanol cannot alleviate US dependence on petroleum

Jul 01, 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: How were fossil tracks made by Early Triassic swimming reptiles so well preserved?

add to favorites email to friend print save as pdf

Related Stories

Unique solar lab shines year-round light in Stockholm

20 minutes ago

Stockholm is one of the world's most sunlight-deprived capitals for almost half of the year. But now, the city's premier technical university, KTH Royal Institute of Technology, is home to one of the world's ...

New 'knobs' can dial in control of materials

20 minutes ago

Designing or exploring new materials is all about controlling their properties. In a new study, Cornell scientists offer insight on how different "knobs" can change material properties in ways that were previously ...

Disappearing lakes stoke megafauna debate

20 minutes ago

New research into central Australia's ancient lakes has found evidence that climate change contributed to the extinction of the continent's megafauna.

Recommended for you

Predicting human crowds with statistical physics

Feb 27, 2015

For the first time researchers have directly measured a general law of how pedestrians interact in a crowd. This law can be used to create realistic crowds in virtual reality games and to make public spaces safer.

Bribery 'hits 1.6 billion people a year'

Feb 27, 2015

A total of 1.6 billion people worldwide – nearly a quarter of the global population – are forced to pay bribes to gain access to everyday public services, according to a new book by academics at the Universities of Birmingham ...

Broken windows thesis springs a leak

Feb 27, 2015

The broken windows theory posits that minor misdemeanors, like littering or graffiti spraying, stimulate more serious anti-social behavior. LMU sociologists now argue that the idea is flawed and does not ...

User comments : 0

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.