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Ethanol more energy-efficient than oil, finds study

Ethanol more energy-efficient than oil, finds study

Ethanol more energy-efficient than oil, finds study
Rhett A. Butler,
January 26, 2006

Using ethanol — alcohol produced from corn or other plants — instead of gasoline is more energy-efficient than oil say researchers at the University of California, Berkeley

In a study published in Friday’s issue of the journal Science, Berkeley scientists show that producing ethanol from corn uses much less petroleum than producing gasoline, though they concede that there is still great uncertainty about greenhouse gas emissions and other environmental effects like soil erosion. Nevertheless the research suggests that at minimum, ethanol is a good substitute for gasoline and thus can help lessen the country’s reliance on imported oil. The study undermines critics who say that the push for ethanol is based solely on intense lobbying by the farm industry.

“It is better to use various inputs to grow corn and make ethanol and use that in your cars than it is to use the gasoline and fossil fuels directly,” said Dan Kammen, one of the lead authors of the study.

“The people who are saying ethanol is bad are just plain wrong,” he continued. “But it isn’t a huge victory – you wouldn’t go out and rebuild our economy around corn-based ethanol.”

Kammen says that despite the uncertainty, it appears that ethanol made from corn is a little better – maybe 10 or 15 percent – than gasoline in terms of greenhouse gas production, but the transition could be worth it if the ethanol is produced not from corn but from cellulose derived from woody, fibrous plants.

“Ethanol can be, if it’s made the right way with cellulosic technology, a really good fuel for the United States,” said Alex Farrell, co-author of the research and an assistant professor of energy and resources at Berkeley. “At the moment, cellulosic technology is just too expensive. If that changes – and the technology is developing rapidly – then we might see cellulosic technology enter the commercial market within five years.”

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According to a news release announcing the research, cellulosic technology refers to “the use of bacteria to convert the hard, fibrous content of plants – cellulose and lignin – into starches that can be fermented by other bacteria to produce ethanol.” Virtually any material from farm waste to specially grown crops or bioengineered trees could be a source of fibrous plant material. Currently millions of tons of such waste material is left unused in the United States.

While in 2004, ethanol blended into gasoline comprised only 2 percent of all fuel sold in the United States, the South American country of Brazil relies heavily on such alcohol-based fuels. The fuel—hydrated alcohol derived from sugar cane—powers more than two million of Brazil’s cars today and produces no benzene or sulfur emissions, and very little carbon dioxide and carbon monoxide. Today ethanol accounts for as much as 20 percent of Brazil’s transport fuel market, and at a production cost of about $1 a gallon offers an economical alternative to drivers throughout the country. The Wall Street Journal estimates that seven out of every 10 new cars sold in Brazil are flex-fuel—capable of running on either traditional gasoline or ethanol.

According to the Berkeley researchers, in the United States there are about 5 million such “flex-fuel” vehicles, including nearly all light trucks now sold. Kammen says the cost of converting a car into a flex-fuel vehicle able to burn a 85 percent ethanol/15 percent gasoline mix fuel is around $100.

“Converting to fuel ethanol will not require a big change in the economy. We are already ethanol-ready. If ethanol were available on the supply side, the demand is there,” Kammen said.

Kammen estimates that ethanol could replace 20 to 30 percent of fuel usage in the United States with little effort in just a few years, but there may be even bigger dividends for developing countries would could reduce their dependence on foreign oil in developing a sustainable local fuel supply that would also provide employment opportunities for rural poor.

Ethanol and cellulosic technology is so promising that leading venture capitalists are funding development efforts. Kammen notes that recently even Bill Gates has shown an interest.

“The investment by Gates is an example of the excitement and seriousness the venture capital community sees in cellulosic technology, which they see as now ready to go prime time,” said Farrell. “Our assessment in the paper is that it is a very strong winner and that the effort needed to go the last 10 percent of the way to get cellulosic on board is actually very small.”

“Two things are going to push the commercialization of cellulosic technology,” Farrell said. “One is driving the cost down, which is mainly research and development; the other is that environmental concerns are increasingly entering into commercial calculations about biofuels.”

This article is based on a news release by Robert Sanders from UC Berkeley.

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