Ethanol or Diesel?

In the Detroit Free Press:

Clean diesel fuel

The government wants to mandate 35 m.p.g. by 2017; automobile manufacturers want to ramp up E85 fuel availability. Presently, average fuel economy is anticipated at 27.5 mpg.

Today's automobiles run on gasoline or 10% ethanol/90% gasoline. Since ethanol contains only 75% of the energy of gasoline, moving to a greater reliance on ethanol would eliminate all of the technology gains required to get a fleet average of 35 m.p.g. True, ethanol would reduce U.S. demand for petroleum, but so would diesel-electric hybrids such as the Ford concept, the Reflex, which would get an estimated 65 m.p.g.

The technology for better mileage exists. European diesel-based powertrains that use clean fuels could be used in the United States, but oil companies in the United States have chosen to take their profits and run rather than produce the fuels that would allow use of these technologies.