Why Do E85 Cars Get Less Gas Mileage?

E85 is a blended fuel composed of 85 percent ethanol and 15 percent gasoline. Cars that can run on E85 are known as flexible fuel vehicles. E85 produces fewer emissions than gasoline and is produced domestically. However, it results in a lower gas mileage than gasoline.

Features

Ethanol contains about 27 percent less stored energy than gasoline. Flexible fuel vehicles usually get 25 to 30 percent lower gas mileage from E85 than from traditional gasoline. Flexible fuel vehicles have a normal fuel economy when using gasoline.

Price

E85 usually costs less than gasoline. In 2010, E85 cost an average of $2.44 per gallon in the United States, while regular gasoline cost $2.78. At these prices, E85 costs more per mile than gasoline, but E85 may be more cost-efficient than gasoline in some regions.

Compatibility

Flexible fuel vehicles look the same as ordinary cars. You may be driving one without realizing it. Look for a yellow gas cap or a label on the fuel door, or check your owner's manual.

References

• FuelEconomy.gov: Ethanol
• FuelEconomy.gov: Flex-Fuel Vehicles
• U.S. Department of Energy: E85: An Alternative Fuel
• U.S. Department of Energy: Clean Cities Alternative Fuel Price Report