Wednesday, July 05, 2006
The False Hope of Biofuels
For Energy and Environmental Reasons, Ethanol Will Never Replace Gasoline
By James Jordan and James Powell
. . .
It's difficult to understand how advocates of biofuels can believe they are a real solution to kicking our oil addiction. Agriculture Department studies of ethanol production from corn -- the present U.S. process for ethanol fuel -- find that an acre of corn yields about 139 bushels. At an average of about 2.5 gallons per bushel, the acre then will yield about 350 gallons of ethanol. But the fuel value of ethanol is only about two-thirds that of gasoline -- 1.5 gallons of ethanol in the tank equals 1 gallon of gasoline in terms of energy output. . . .
But allowing a net positive energy output of 30,000 British thermal units (Btu) per gallon, it would still take four gallons of ethanol from corn to equal one gallon of gasoline. The United States has 73 million acres of corn cropland. At 350 gallons per acre, the entire U.S. corn crop would make 25.5 billion gallons, equivalent to about 6.3 billion gallons of gasoline. The United States consumes 170 billion gallons of gasoline and diesel fuel annually. Thus the entire U.S. corn crop would supply only 3.7 percent of our auto and truck transport demands. Using the entire 300 million acres of U.S. cropland for corn-based ethanol production would meet about 15 percent of the demand. . . .
Similar limitations and problems apply to growing any crop for biofuels, whether switchgrass, hybrid willow, hybrid poplar or whatever. Optimistically, assuming that switchgrass or some other crop could produce 1,000 gallons of ethanol per acre, over twice as much as we can get from corn plus stover, and that its net energy was 60,000 Btu per gallon, ethanol from 300 million acres of switchgrass still could not supply our present gasoline and diesel consumption, which is projected to double by 2025. The ethanol would meet less than half of our needs by that date.
Perhaps more important: The agricultural effects of such a large-scale program would be devastating. . . .
Finally, considering projected population growth in the United States and the world, the humanitarian policy would be to maintain cropland for growing food -- not fuel. Every day more than 16,000 children die from hunger-related causes -- one child every five seconds. The situation will only get worse. It would be morally wrong to divert cropland needed for human food supply to powering automobiles. It would also deplete soil fertility and the long-term capability to maintain food production. We would destroy the farmland that our grandchildren and their grandchildren will need to live.