The stickiest question about ethanol is this: Does making alcohol from grain or plant waste really create any new energy?

The answer, of course, depends upon whom you ask. The ethanol lobby claims there's a 30 percent net gain in BTUs from ethanol made from corn. Other boosters, including Woolsey, claim there are huge energy gains (as much as 700 percent) to be had by making ethanol from grass.

But the ethanol critics have shown that the industry calculations are bogus. David Pimentel, a professor of ecology at Cornell University who has been studying grain alcohol for 20 years, and Tad Patzek, an engineering professor at the University of California, Berkeley, co-wrote a recent report that estimates that making ethanol from corn requires 29 percent more fossil energy than the ethanol fuel itself actually contains.

The two scientists calculated all the fuel inputs for ethanol production—from the diesel fuel for the tractor planting the corn, to the fertilizer put in the field, to the energy needed at the processing plant—and found that ethanol is a net energy-loser. According to their calculations, ethanol contains about 76,000 BTUs per gallon, but producing that ethanol from corn takes about 98,000 BTUs. For comparison, a gallon of gasoline contains about 116,000 BTUs per gallon. But making that gallon of gas—from drilling the well, to transportation, through refining—requires around 22,000 BTUs.