Basic chemistry dictates that gallon for gallon, burning ethanol produces only 2/3 as much energy as burning gasoline. In recent years, Americans have become accustomed to E15 “gasohol” (15% ethanol) at the pumps. Due to government regulations, it’s now extremely rare to find a gas station with ethanol-free gasoline in the US.
This means that the efficiency of E15, measured in miles per gallon, can never exceed 95% of the efficiency of regular gasoline. In actuality, it tends to be far lower. For most cars, ethanol mixes are detrimental to fuel efficiency. For example, the EPA tested 2006 flex-fuel models and determined that with E85 there was an average MPG reduction of 26%. Vehicles advertised as 30 MPG for regular gasoline typically get 22.2 MPG with E85 at the pump.
Person I’m thinking of as I blog this: Michael Silence. He’s been a big promotor of local sources of ethanol-free gasoline.