AMES, Iowa — The endless fields of corn in the Midwest can be distilled into endless gallons of ethanol, a clean-burning, high-octane fuel that could end any worldwide oil shortage, reduce emissions that cause global warming, and free the United States from dependence on foreign energy.
There is only one catch: Turning corn into ethanol takes energy. For every gallon that an ethanol manufacturing plant produces, it uses the equivalent of almost two-fifths of a gallon of fuel (usually natural gas), and that does not count the fuel needed to make fertilizer for the corn, run the farm machinery or truck the ethanol to market.
The use of all that fossil fuel to make ethanol substantially reduces its value as an alternative source of energy. Not that ethanol is useless. For one thing, it is far easier than natural gas to use in motor vehicles.
Production is expected to hit five billion gallons this year, equal to more than 3 percent of gasoline supplies, and more ethanol distilleries are being built.
But if ethanol is to realize its potential, its proponents recognize that they will have to develop new ways to make it without using so much natural gas — or coal, as some distilleries are doing to save money.
http://www.nytimes.com/2006/02/07/science/07fuel.html?pagewanted=print