In the 1970s and 1980s, when that energy crisis caused scientists and politicians to start the hunt for a gasoline substitute,
were brought to the table as possible replacement fuels. Butanol, an alcohol that can be derived from fermentation or from petroleum, showed promise: it burns cleaner than ethanol, has a higher energy output, can travel through existing gasoline pipelines, and can be used at 100% concentrations in unmodified vehicles. So why did ethanol win the federal dollars for development? Because manufacturing butanol was expensive and inefficient, and the same bushel of corn could make 2.5 gallons of ethanol, but only 1.3 gallons of butanol.
In 2004, Environmental Energy, Inc announced that they had developed a manufacturing process that could yield 2.5 gallons of butanol per bushel of corn, and could even create butanol out of switch grass and yard waste. The last information the company gives is that it's still raising money to step their production into high gear. Perhaps Bush's new call to invest in alternative energy will give butanol a chance.
[Source: Environmental Energy Inc., and thank you to Stéphane Dumas for the tip.]