The AP reports that the proposed Senate energy bill includes provisions that double the use of ethanol in gasoline.

Advocates, like the Canadian Renewable Fuels Association, claim that blended gasoline does not lower fuel efficiency in practice. Quoth the CRFA:

Studies with 10% ethanol-blended gasoline show that actual fuel efficiency is essentially identical to that of regular (ethanol free) gasoline. Yet ethanol contains less caloric energy than gasoline, which should, theoretically, result in poorer fuel efficiency. The discrepancy results from the greater efficiency with which ethanol-blended gasoline is burned during engine operation.

This advocacy site claims a 2% reduction in efficiency, but that it is “a small price to pay for a cleaner environment.”

On the other hand, some auto enthusiasts believe that ethanol lowers the fuel efficiency by ten percent or more (negating the savings on gasoline, and effectively increasing the cost to operate the vehicle per mile), although it does increase the octane rating of the gasoline. And anything that feeds more money to ArcherDanielsMidland (motto: “We keep the Sunday shows on the air.”) and our obscenely over-subsidized farming industry leaves me somewhat skeptical.