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Thursday, Oct. 20, 2005 11:12 am

Earth Talk

From the editors of E/The Environmental Magazine

Dear “Earth Talk”: Is it true that converting crops such as corn into ethanol actually uses more energy than is produced? — Leslie Foster, Eau Claire, Wis.
Recent revelations by University of California, Berkeley, researcher Tad Patzek have fueled vigorous debate about the wisdom of using fuels such as ethanol to reduce our reliance on oil and our contribution to global warming. Patzek concluded that the production of ethanol actually uses more energy than the resulting fuel can generate. “Ethanol production using corn grain required 29 percent more fossil energy than the ethanol fuel produced,” reported Patzek in the journal Natural Resources Research last winter. Ethanol produced from other common sources, such as wood products and agricultural waste, uses up even more fossil-fuel-derived energy. “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,” says Patzek, “but that isn’t the case. Fossil fuel actually drives the whole cycle.”
Ethanol is primarily in use today as an octane-boosting fuel additive, but it is also used as a primary fuel in some engines. Most gasoline sold in North America today contains about 5 percent ethanol, but some vehicles — such as the Ford Explorer and Chevy Silverado — can run on blends of as much as 85 percent ethanol. To stimulate production, the United States offers generous tax-based subsidies to farmers who grow crops for ethanol. Although Patzek’s evidence may be compelling, his views on ethanol are not popular. Critics point out that his findings are based on farming and production practices that are fast becoming obsolete and that newer techniques and machinery can make the ethanol-production process much more energy-efficient.
Hosein Shapouri, an economist at the U.S. Department of Agriculture, estimates that ethanol fuel can actually generate 67 percent more energy than it takes to produce it. He points out that
scientists are experimenting with alternative sources such as solid waste, grass, and wood to make the ethanol production-process that much more energy-efficient.

Although the jury may still be out as to whether ethanol production can generate a positive or negative “energy balance,” ethanol production does hold some hazards. For instance, the nitrogen fertilizer needed to grow corn and other crops ends up in waterways, causing “algae blooms” that may choke out other life in affected areas. And although ethanol produces fewer carbon monoxide emissions than does regular gasoline, it contributes significantly to low-lying smog. Doubts about ethanol underscore a fundamental problem in getting many types of renewable energy sources, including hydrogen, into mainstream use: Until fuel sources such as solar or wind power can provide clean ways to make clean fuel, the processes must rely on coal, oil, gas, and nuclear energy. Indeed, although we may be able to see a clean energy future, we are still wrangling with how to get there.
For more information: U.S. Department of Energy Ethanol Facts, www.eere.energy.gov/biomass/ethanol.html.
Send questions to “Earth Talk” in care of E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; or e-mail earthtalk@emagazine.com.
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