U.S. Department of Energy - Energy Efficiency and Renewable Energy
Vehicle Technologies Office
Fact #588: September 14, 2009
Fuel Economy Changes Due to Ethanol Content
The fuel economy of a vehicle is dependent on many things, one of which is the fuel used in the vehicle. Two National Laboratories recently studied the effects that ethanol blends have on the fuel economy of light vehicles. The results are not surprising, since a gallon of ethanol does not have as much energy as a gallon of gasoline. A blend of gasoline with 10% ethanol (E10) will result in a 3.7% decline in fuel economy over gasoline without ethanol (E0), while a blend of gasoline with 20% ethanol (E20) results in a 7.7% decline in fuel economy over E0.
Fuel Economy Decline for Various Ethanol Blends 
Supporting Information
Decline in Fuel Economy due to Ethanol Blends
| Fuel |
Share of Ethanol in Gasoline |
Fuel Economy Loss |
| E0 |
0% ethanol |
0.0% |
| E10 |
10% ethanol |
3.7% from E0 |
| E15 |
15% ethanol |
5.3% from E0 |
| E20 |
20% ethanol |
7.7% from E0 |
|
Source: Oak Ridge National Laboratory and National Renewable Energy Laboratory, Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines, Report 1 – Updated, February 2009, Table 3.1 (PDF 1.4 MB). Download Adobe Reader. |
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