Ethanol is a renewable fuel made from corn and other biomass (plant) materials, then blended with gasoline. More than 90 percent of gas in the U.S. contains some ethanol.

Emissions requirements often depend on the state in which the carrier operates. Ethanol may be suitable for some fleets.

This article examines the basics of ethanol and how it may help reduce emissions and lower fuel costs.

Common blends

Ethanol is added to conventional gasoline to boost octane (resistance of motor fuel to knock) and reduce tailpipe emissions. Ethanol blends are not zero-emissions fuels and may increase net emissions when considering the entire production process through tailpipe emissions.

However, carbon dioxide (CO2) tailpipe emissions can be reduced by up to 40 percent compared to gasoline and diesel due to CO2 from the crops grown to produce ethanol, depending on the blend.

Both E10 and E15, discussed below, do not qualify as an alternative fuel, as compared to petroleum-based fuels, under the Energy Policy Act of 1992 but are approved by the Environmental Protection Agency (EPA) for use in any highway vehicle gasoline engine manufactured in 2001 and later.

• E10 is the most common blend and is 10 percent ethanol and 90 percent gasoline. E10 is sold in every state.E15 is 15 percent ethanol and 85 percent gasoline.
• E15 can be used in light-duty gasoline vehicles produced in 2001 and later. However, E15 can cause damage to off-road vehicles and model year 2000 and earlier vehicles. E15 fuel pumps must be labeled to avoid misfueling.

E85 can be used in "flex-fuel" vehicles (FFVs) that run on a blend of 51 to 83 percent ethanol mixed with gasoline. E85 is considered an alternative fuel.

Based on fueleconomy.gov, E85 aspects to examine are:

Performance - There is no performance loss when using E85, and some FFVs have more torque and horsepower with E85 than on regular gasoline.

Availability - E85 is widely available as it is sold at 4,307 filling stations in the U.S., according to the Department of Energy's (DOE) Alternative Fuels Data Center (AFDC).

Fuel efficiency - Due to ethanol's lower energy content, FFVs operating on E85 achieve 15 to 27 percent fewer miles per gallon than regular gasoline, depending on the ethanol content. E85 is typically cheaper per gallon than gasoline (see the table below) but slightly more expensive per mile. The AFDC showed the October 1 - 15, 2023, national average price per gallon as follows:

E85 was 33 percent cheaper than diesel and 18 percent cheaper than gasoline in this period.

Can E85 be used in diesel vehicles?

Not yet, is the short answer. Testing is being conducted to run E85 and up to a 98 percent blend of ethanol in diesel engines, but these engines are not yet in production. Ethanol diesel engine technology promises to reduce emissions, lower fuel costs, and maintain performance.

Keys to remember: Ethanol is an option to reduce emissions over gasoline vehicles but may cost more per mile for the fuel if E85 is used. Ethanol diesel engines are not yet in mainstream production but are being tested .