Ethanol
Basics
Ethanol is a renewable fuel made from various plant materials known as biomass. Biomass feedstock is grown, collected, and transported to a facility, where is is converted to ethanol. Then the material is transported to a fuel terminal where it is blended with gasoline and then distributed to fueling stations. Ethanol, like biodiesel, is generally mixed with gasoline to make blends called E10, E15, and E85, also known as flex fuel. The use of ethanol is widespread, with more than 95 percent of U.S. gasoline containing ethanol in a low-level blend to oxygenate the fuel and reduce air pollution.
Ethanol is a natural, non-toxic alcohol that burns clean and reduces greenhouse emissions by as much as 59 percent. Most ethanol is currently made from field corn, but new technologies are allowing ethanol to be made from other materials such as switchgrass, wood chips and agricultural waste.
Uses
Ethanol is used widely throughout the country and is found in more than 98% of gasoline. The most common type of blend is E10, which contains 10% ethanol, 90% gasoline. Ethanol is also available as E85 (or flex fuel)—a high-level ethanol blend containing 51% to 83% ethanol, depending on geography and season—for use in flexible fuel vehicles (FFVs). Common applications for E85 include non-diesel fleet vehicles, buses, light-duty vehicles and delivery trucks. Other than an ethanol-compatible fuel system and a different powertrain calibration, FFVs are similar to their conventional gasoline counterparts. E15 is defined as a blend of 10.5% to 15% ethanol with gasoline. E15 is an approved ethanol blend for use in model year 2001 and newer light-duty conventional gas vehicles.
Benefits
Like all alternative fuels, biodiesel produces less tailpipe emissions and improves national security. Ethanol production in particular is responsible for huge job growth in rural areas, where most of the crops are grown. In 2017, ethanol production accounted for more than 71,900 direct jobs across the country, $45 billion to the GDP, and $24 billion to household income. Ethanol also has a higher octane number than gasoline, providing increased power and performance.
Considerations
Unfortunately, high percentages of ethanol like those found in flex fuel have less energy content than gas which lowers the vehicle’s fuel economy. This is because the engines are optimized at a certain level, but if engines were to be optimized to run on higher ethanol blends, the fuel economy would increase. As with conventional fuels, the use and storage of ethanol blends can result in emissions of regulated pollutants, toxic chemicals, and greenhouse gases (GHGs), but these emissions are reduced with higher percentages of ethanol.
Further Reading
The Alternative Fuel Data Center further explains the production, distribution, incentives, and technology involved with electric vehicles