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. “Since E85 is also the cleanest fuel on the market and contains so little petroleum-based gasoline, it has a very positive impact on the environment and can significantly reduce our use of foreign oil.”
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.
“Fuel economy is actually a combination of fuel efficiency and fuel price, and on that point, higher ethanol blends may be the better choice,” says Isom, who is with the University of Nebraska’s Industrial Agricultural Products Center. “It just depends on fuel prices at the time. Specific vehicles may test out differently based on engine design and settings, but increased efficiency from ethanol blends make sense, and for the fuel prices we looked at in the study, E85 was the best choice every time.”
In addition to Isom, the study was conducted by the University of Nebraska’s Milford Hanna and Robert Weber. While the Nebraska Corn Board funded the project, additional support was provided by the State of Nebraska Transportation Services Bureau, which provided the flex-fuel vehicles used in the tests, and The Shop Inc., where the tests were conducted.
“Despite fewer BTUs per gallon, E85 was the lowest-cost fuel per mile and the most efficient fuel in the study,” Klein says. “At the same time, E85 significantly reduces the use of oil-based gasoline, making it an outstanding choice for drivers with flex-fuel vehicles.”