Study: ethanol use worse than gasoline

February 8, 2008 7:12:15 AM PST
Hold that rush to convert all vehicles to ethanol-based fuel. A new study says it is no better. In fact, it says it is actually twice as worse as using gasoline.Researchers affiliated with a number of institutions, including Princeton University, Iowa State University, the Woods Hole Research Center and the Agricultural Conservation Economics, compiled the study. It was published in Science magazine.

The study says using cropland to expand the production of biofuels would exacerbate global warming because of land-use changes. Ethanol is extracted mostly from corn, but also from feedstock like switchgrass and wood chips.

Past studies have touted the use of ethanol to fuel vehicles instead of traditional gasoline, in efforts to combat climate change. But the researchers in this new study say those past studies did not take into account what would happen if ethanol from corn, or other crops, would become a prized commodity.

The researchers said economic pressures to produce biofuels would "plow up more forest or grasslands," and the act of clearing land for farming would release much of the carbon formerly stored in plants and soils through decomposition or fires.

The Renewable Fuels Association, which represents ethanol producers, called that view simplistic and out of context.

"Assigning the blame for rainforest deforestation and grassland conversion to agriculture solely on the renewable fuels industry ignores key factors that play a greater role," said Bob Dinneen, the association's president.

Burning ethanol as a fuel produces less carbon dioxide, the leading greenhouse gas, than traditional fossil fuels.

The lead author of the study, however, says that doesn't tell the whole story.

"The other studies missed a key factor that everyone agrees should have been included, the land use changes that actually are going to increase greenhouse gas emissions," said Tim Searchinger, a research scholar at Princeton University's Woodrow Wilson School of Public and International Affairs.

Searchinger says after taking into account expected worldwide land-use changes, corn-based ethanol would not reduce greenhouse gases by 20 percent, as some studies have suggested. Instead, his study says, it would increase them by 93 percent, compared to using gasoline, over a 30-year period.

If biofuels are obtained from switchgrass instead of corn, Searchinger believes it would result in 50 percent more greenhouse gas emissions (again, compared to gasoline).

"We should be focusing on our use of biofuels from waste products" such as garbage, which would not result in changes in agricultural land use, Searchinger said. "And you have to be careful how much you require. Use the right biofuels, but don't require too much too fast. Right now we're making almost exclusively the wrong biofuels."

WEB LINK: Read the report in Science Magazine