Corn based ethanol is a joke that is only kept alive by government subsidy. To produce 100 gallons of ethanol from corn requires 32 gallons of foreign oil , 22 gallons of corn , and 42 gallons of coal. See zfacts.com. If all the corn crop of the USA was devoted to ethanol production , it would replace 3.7% of foreign oil needs. Cellulose ethanol doesn't use corn. It uses sugar cane , praire grass , trees , feed left overs , and the like. But it still requires huge carbon energy inputs to distill the ethanol. Cellulose ethanol would require 10's of millions of acres dedicated to raw material growth. The nitrogen fertilizers would still pollute the fields. Ethanol compared to gasoline and diesel would only reduce co2 emissions about 1%. Still because ethanol is a liquid , it can more easily be used in current technology cars and trucks than hydrogen which is a gas. So ethanol is an intermediate solution. N1R thinks it would be better to spend the billions of dollars on short term hydrogen fuel cell solutions and longer term hydrogen combustion engines than feel good ethanol intermediate solutions.