Ethanol: Behind the Buzz

Ethanol from corn is costlier, dirtier and less efficient than sugar-based ethanol. Because corn contains less energy and is more difficult to convert into fuel, it yields a meager 1.3:1 energy balance at a 50% higher direct cost than sugar ethanol. Net greenhouse gas emissions are little better than gasoline and prospects for growth are constrained by limited cropland and competition from food markets. Simply meeting President Bush's 35-billion-gallon oil reduction goal through domestic ethanol production would require doubling U.S. corn output.

However, what corn ethanol lacks in intrinsic value, it more than compensates for in political clout. Powerful agribusiness lobbies and farm-state representatives in the U.S. have worked to secure huge subsidies for corn ethanol and to erect powerful barriers to imported sugar ethanol. The U.S.' longstanding 54-cents-per-gallon tariff on imported ethanol effectively nullifies sugar ethanol's intrinsic cost advantage, and corn subsidies that exceeded $8 billion last year drive input costs to artificially low levels.

Cellulosic ethanol is the holy grail of biofuels. It can be collected from a much wider variety of biomass than corn or sugar plants, including agricultural refuse, switchgrass and wood. However, its conversion is also more difficult. Long cellulose chains that form plant walls must be broken down to obtain sugars for fermentation. A host of methods are currently under study and some demonstration-scale plants are operational. Nevertheless, the technology remains unproven on an industrial scale and commercial viability lies years away.

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