Increased Ethanol Drops Energy Content Of Gas

By Christopher Doering

The growing use of ethanol in the country’s gasoline supply has reduced the average energy content of a gallon of gasoline by about 3 percent during the last two decades, the government said Monday.

The Energy Department’s statistical arm said the drop in energy content per gallon comes as the use of ethanol and other oxygenates, which have lower energy content than petroleum-based gasoline components, have seen their share of total gasoline volumes increase from 2 percent in 1993 to nearly 10 percent in 2013.

In 2013, about 135 billion gallons of motor gasoline (3.2 billion barrels) were consumed in the United States, which contained about 13 billion gallons of ethanol.

The higher the ethanol content the less fuel efficient the gallon of gasoline. For example, even though E85 (fuel with 85 percent ethanol and 15 percent gasoline) is usually cheaper, a car using the fuel would see its mileage lowered by 29 percent compared to pure gasoline, according to the DOE.

Supporters of the largely corn-based fuel have criticized the oil industry and other groups for putting roadblocks in place to prevent and discourage the sale of blends containing more than 10 percent ethanol. Despite the Environmental Protection Agency’s approval of E15 and tests from the agency showing the fuel is safe, the oil and gas industry, AAA, and others have warned of possible damage to car engines from using the fuel.