The fossil energy expended during production alone, he concluded, easily outweighs the consumable energy in the end product. As a result, Patzek believes that those who think using the "green" fuel will reduce fossil fuel consumption are deluding themselves -- and the federal government's practice of subsidizing ethanol by offering tax exemptions to oil refiners who buy it is a waste of money. "People tend to think of ethanol and see an endless cycle: corn is used to produce ethanol, ethanol is burned and gives off carbon dioxide, and corn uses the carbon dioxide as it grows," he said. "But that isn't the case. Fossil fuel actually drives the whole cycle." Patzek's investigation into the energy dynamics of ethanol production began two years ago, when he had the students in his Berkeley freshman seminar calculate the fuel's energy balance as a class exercise. Once the class took into account little-considered inputs like fossil fuels and other energy sources used to extrude alcohol from corn, produce fertilizers and insecticides, transport crops and dispose of wastewater, they determined that ethanol contains 65 percent less usable energy than is consumed in the process of making it. Surprised at the results, Patzek began an exhaustive analysis of his own -- one that painted an even bleaker picture of the ethanol industry's long- term sustainability. "Taking grain apart, fermenting it, distilling it and extruding it uses a lot of fossil energy," he said. "We are grasping at the solution that is by far the least efficient."Even though Patzek's research was published in a peer-reviewed journal, There are scientists who disagree.
David Morris, an economist and vice president of the Minneapolis-based Institute for Local Self-Reliance, has attacked the Berkeley professor's analysis because he says it is based on farming and production practices that are rapidly becoming obsolete..... Hosein Shapouri, an economist at the U.S. Department of Agriculture, has also cracked down on Patzek's energy calculations. "It's true that the original ethanol plants in the 1970s went bankrupt. But Patzek doesn't consider the impact new, more efficient production technologies have had on the ethanol industry," he said.But there are also others who agree:
Cornell University ecology Professor David Pimentel, however, sides with Patzek, calling production of ethanol "subsidized food burning." "The USDA isn't looking at factors like the energy it takes to maintain farm machinery and irrigate fields in their analysis," he said, adding that the agency's ethanol report contains overly optimistic assumptions about the efficiency of farming practices. "The bottom line is that we're using far more energy in making ethanol than we're getting out."