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Sugar-cane ethanol
Sugar-cane ethanol

Pluses: Sugar cane yields more ethanol per acre than corn, and it requires less energy to produce; hence, it is regarded as greener than corn ethanol. Sugar isn't a food staple, so making ethanol from it hasn't driven up food prices as has the production of large amounts of corn ethanol. Brazil makes nearly as much ethanol from sugar cane as the U.S. does from corn; cane provides nearly half of Brazil's transportation fuel from plants grown using about 1% of its arable land.

Minuses: Growing sugar cane requires a warm, rainy climate, which limits its potential as a global fuel source.

NEXT: Cellulosic ethanol
Last updated April 22 2008: 7:09 AM ET