In 2004, approximately 3.57 billion gallons of ethanol were used as a gas additive in the United States, according to the Renewable Fuels Association (RFA). During the February State of the Union address, President George Bush urged Congress to pass an energy bill that would pump up the amount to 5 billion gallons by 2012. UC Berkeley geoengineering professor Tad W. Patzek thinks that's a very bad idea.

For two years, Patzek has analyzed the environmental ramifications of ethanol, a renewable fuel that many believe could significantly reduce our dependence on petroleum-based fossil fuels. According to Patzek though, ethanol may do more harm than good.

"In terms of renewable fuels, ethanol is the worst solution," Patzek says. "It has the highest energy cost with the least benefit."

Ethanol is produced by fermenting renewable crops like corn or sugarcane. It may sound green, Patzek says, but that's because many scientists are not looking at the whole picture. According to his research, more fossil energy is used to produce ethanol than the energy contained within it.

Patzek's ethanol critique began during a freshman seminar he taught in which he and his students calculated the energy balance of the biofuel. Taking into account the energy required to grow the corn and convert it into ethanol, they determined that burning the biofuel as a gasoline additive actually results in a net energy loss of 65 percent. Later, Patzek says he realized the loss is much more than that even.

"Limiting yourself to the energy balance, and within that balance, just the fossil fuel used, is just scraping the surface of the problem," he says. "Corn is not 'free energy.'"

Recently, Patzek published a fifty-page study on the subject in the journal Critical Reviews in Plant Science. This time, he factored in the myriad energy inputs required by industrial agriculture, from the amount of fuel used to produce fertilizers and corn seeds to the transportation and wastewater disposal costs. All told, he believes that the cumulative energy consumed in corn farming and ethanol production is six times greater than what the end product provides your car engine in terms of power.

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Patzek is also concerned about the sustainability of industrial farming in developing nations where surgarcane and trees are grown as feedstock for ethanol and other biofuels. Using United Nations data, he examined the production cycles of plantations hundreds of billions of tons of raw material.

"One farm for the local village probably makes sense," he says. "But if you have a 100,000 acre plantation exporting biomass on contract to Europe , that's a completely different story. From one square meter of land, you can get roughly one watt of energy. The price you pay is that in Brazil alone you annually damage a jungle the size of Greece ."

If ethanol is as much of an environmental Trojan horse as Patzek's data suggests, what is the solution? The researcher sees several possibilities, all of which can be explored in tandem. First, he says, is to divert funds earmarked for ethanol to improve the efficiency of fuel cells and hybrid electric cars.

"Can engineers double the mileage of these cars?" he asks. "If so, we can cut down the petroleum consumption in the US by one-third."

For generating electricity on the grid, Patzek's "favorite renewable energy" to replace coal is solar. Unfortunately, he says that solar cell technology is still too immature for use in large power stations. Until it's ready for prime time, he has a suggestion that could raise even more controversy than his criticisms of ethanol additives.

"I've come to the conclusion that if we're smart about it, nuclear power plants may be the lesser of the evils when we compare them with coal-fired plants and their impact on global warming," he says. "We're going to pay now or later. The question is what's the smallest price we'll have to pay?"