A new study released today by the American Coalition for Ethanol shows that mid-range ethanol blends – fuel mixtures with more ethanol than E10 but less than E85 – can in some cases provide better fuel economy than regular unleaded gasoline, even in standard, non-flex-fuel vehicles.

The new research strongly suggests that there is an “optimal blend level” of ethanol and gasoline – most likely E20 or E30 – at which cars will get better mileage than predicted based strictly on the fuel’s per-gallon Btu content. The new study, co-sponsored by the U.S. Department of Energy and the American Coalition for Ethanol (ACE), also found that mid-range ethanol blends reduce harmful tailpipe emissions.

The University of North Dakota Energy & Environmental Research Center (EERC) and the Minnesota Center for Automotive Research (MnCAR) conducted the research using four 2007 model vehicles: a Toyota Camry, a Ford Fusion, and two Chevrolet Impalas, one flex-fuel and one non-flex-fuel. Researchers used the EPA Highway Fuel Economy Test (HWFET) to examine a range of ethanol-gasoline blends from straight Tier 2 gasoline up to 85 percent ethanol. All of the vehicles got better mileage with ethanol blends than the ethanol’s energy content would predict, and three out of four actually traveled farther on a mid-level ethanol blend than on unleaded gasoline.

PDF file of the report can be found here.