December 05, 2007
A study conducted by the University of North Dakota Energy & Environmental Research Center (EERC) and the Minnesota Center for Automotive Research (MnCAR) shows that mid-level ethanol blends such as E20 and E30 may be the optimal for todays new cars.
Although this test is limited and only conducted on four cars, all 2007 models, it shows that conventional wisdom that ethanol should get less mileage based on the fact that it has a lower energy content than gasoline is incorrect. Three of the four test cars showed better fuel mileage on ethanol blends than on regular gasoline. And all four cars outperformed the mileage that would be predicted based solely on energy content.
Full Study (PDF)