Posted by jack cain on Wednesday, May 04, 2005 at 6:39PM :
In Reply to: Re: They said at $3 gal, corn or shale oil become economically f posted by Chewie on Wednesday, May 04, 2005 at 3:39PM :
From - David Pimentel Cornell College of Agriculture and Life Sciences. And this was before the recent run-up in the price of oil.
An acre of U.S. corn yields about 7,110 pounds of corn for processing into 328 gallons of ethanol. But planting, growing and harvesting that much corn requires about 140 gallons of fossil fuels and costs $347 per acre, according to Pimentel's analysis. Thus, even before corn is converted to ethanol, the feedstock costs $1.05 per gallon of ethanol.
o The energy economics get worse at the processing plants, where the grain is crushed and fermented. As many as three distillation steps are needed to separate the 8 percent ethanol from the 92 percent water. Additional treatment and energy are required to produce the 99.8 percent pure ethanol for mixing with gasoline. o Adding up the energy costs of corn production and its conversion to ethanol, 131,000 BTUs are
needed to make 1 gallon of ethanol. One gallon of ethanol has an energy value of only 77,000 BTU. "Put another way," Pimentel says, "about 70 percent more energy is required to produce ethanol than the energy that actually is in ethanol. Every time you make 1 gallon of ethanol, there is a net energy loss of 54,000 BTU."
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