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Corn ethanol
Corn ethanol

Pluses: May reduce U.S. reliance on oil imports and enable moderate reduction in emissions of greenhouse gases compared with oil. Fosters the building of biofuels infrastructure.

Minuses: Ethanol is energy intensive to produce, and the recent boom has pushed corn prices to more than $5 a bushel (from $2 in 2006). That is increasing the cost of everything from beef to soft drinks. The biofuels craze is helping drive up grain prices worldwide as farmers devote more acres to corn and less to other crops. Over 450 pounds of corn are needed to fill a 25-gallon tank with ethanol_ enough calories to feed a person for a year.

NEXT: Biodiesel
Last updated April 22 2008: 7:09 AM ET