Study Shows Mid-Range Ethanol Blends Provide Better Fuel Economy

There is a common scientific assumption that a fuel with a lower energy content would provide a lower fuel economy in cars. (Fuel economy is often measured in terms of distance travelled per unit amount of fuel, i.e. “miles to the gallon”). Ethanol has a lower energy content compared to gasoline and has always been assumed to have a lower fuel economy than gasoline.

A new study (by the University of North Dakota Energy & Environmental Research Center (EERC) and the Minnesota Center for Automotive Research (MnCAR)), however, has disproven this assumption. They found that in certain cases, ethanol blends greater than E10 (10% ethanol blend) and lower than E85 (85% ethanol blend), provide better fuel economy than regular unleaded gasoline. Furthermore, a reduction in carbon dioxide emissions was found in cars running on “optimal” ethanol blends. This observation was observed even in standard, non-flex fuel cars. (Non-flex fuel cars are those whose engines have not been modified to run on non-gasoline fuel sources, like ethanol). The results by the study group showed that the most likely optimal ethanol blends for standard, non-flex fuel cars would be in the range of E20 to E30. Details of the study can be accessed from the URL above.

Related information on fuel economy and flex fuel vehicles: http://en.wikipedia.org/wiki/Fuel_economy 
http://en.wikipedia.org/wiki/Flexible-fuel_vehicle