High-ethanol blends provide better energy conversion within an engine than other fuels — meaning you can travel farther on less energy, according to a study conducted by the University of Nebraska and funded by the Nebraska Corn Board.
“What this suggests is that the increased efficiency of ethanol has a more positive impact as a replacement for petroleum fuel than what it is commonly given credit for,” says Randy Klein, director of market development for the Nebraska Corn Board.
“It also suggests that E85, which contains 85% ethanol and only 15% petroleum-based gasoline, may be the most efficient and often the most cost-effective fuel for flex-fuel vehicles,” he says.
The report, which is available from the Nebraska Corn Board, says E85 improved energy conversion by 13%, 9% and 14%, respectively, when compared to E10, for the light-, medium- and heavy-loaded vehicles tested.
The researchers acknowledged that higher ethanol blends like E85 have a lower energy density, or fewer BTUs per gallon, than E10. That often leads to fewer miles per gallon for higher ethanol blends, but that gets partly offset by ethanol's improved efficiency.
“While fewer Btus typically means fewer miles per gallon, energy density is only part of the equation when considering fuel economy,” says Loren Isom, one of the researchers in the study.