Frequently Asked Questions

How much ethanol is in gasoline and how does it affect fuel economy?

In 2014, about 13 billion gallons of fuel ethanol were added to the motor gasoline produced in the United States. Fuel ethanol accounted for about 10% of the total volume of finished motor gasoline consumed.

Most of the gasoline now sold in the United States contains some ethanol, but the exact amount varies by region. In general, the ethanol content of motor gasoline does not exceed 10% by volume. Gasoline with 10% ethanol content is referred to as E10, and gasoline with 15% ethanol content is called E15. E85 is a fuel that averages 85% ethanol and 15% gasoline. Most of the motor gasoline with more than 10% ethanol is sold in the Midwest.

All gasoline vehicles can use E10. Currently only light-duty vehicles with a model year 2001 or greater can use E15. Only flex-fuel vehicles can use gasoline with an ethanol content greater than E15.

The energy content of ethanol is about 33% less than pure gasoline, although this varies depending on the amount of denaturant that is added to the ethanol. Therefore, vehicle fuel economy may decrease by up to 3.3% when using E10.

Learn more:

U.S. petroleum supply and disposition

Articles on ethanol

Issues and Methods for Estimating the Share of Ethanol in the Motor Gasoline Supply

Biofuels Issues and Trends

Last updated: April 3, 2015

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