Ethanol Benefits and Considerations
Ethanol is a renewable, domestically produced transportation fuel. Whether used in low-level blends, such as E10 (10% ethanol, 90% gasoline), E15 (10.5% to 15% ethanol), or E85 (flex fuel)—a gasoline-ethanol blend containing 51% to 83% ethanol, depending on geography and season—ethanol improves public health and the environment, provides safety benefits, and contributes to a resilient transportation system. Like any alternative fuel, the use of ethanol involves several considerations.
Public Health and the Environment
The transportation sector is the largest source of greenhouse gas emissions in the United States. A successful transition to clean transportation will require various vehicle and fuel solutions and must consider life cycle emissions. The carbon dioxide released by a vehicle when ethanol is burned is offset by the carbon dioxide captured when the feedstock crops are grown to produce ethanol. This differs from gasoline and diesel, which are refined from petroleum extracted from the earth. No emissions are offset when these petroleum products are burned. On a life cycle analysis basis, greenhouse gas (GHG) emissions are reduced on average by 40% with corn-based ethanol produced from dry mills, and reductions range between 88% and 108% if cellulosic feedstocks are used depending on feedstock type, compared with gasoline and diesel production and use. (See the Life-Cycle Greenhouse Gas Emission Reductions of Ethanol with the GREET Model.)
To learn more about fuel economy, GHG scores, and U.S. Environmental Protection Agency smog scores for FFVs, visit FuelEconomy.gov, or see the Alternative Fuel and Advanced Technology Vehicles list.
Fuel Economy and Performance
The impact to fuel economy varies depending on the energy difference in the blend used. For example, E85 that contains 83% ethanol content has about 27% less energy per gallon than gasoline (the impact to fuel economy lessens as ethanol content decreases). Ethanol impacts fuel economy in part because flex-fuel vehicles (FFVs) are optimized for gasoline. If they were optimized to run on higher ethanol blends, fuel economy would likely increase as a result of increased engine efficiency.
Ethanol also has a higher octane number than gasoline, which provides increased power and performance. For example, IndyCar drivers often fuel their race cars with E98 because of its high octane. The Co-Optimization of Fuels and Engines initiative researched the potential to improve engine efficiency through the use of ethanol blends and other high-octane biofuels.
Job Impacts
Ethanol production creates jobs in rural areas where employment opportunities are needed. According to the Renewable Fuels Association, ethanol production in 2022 accounted for nearly 79,000 direct jobs across the country, $57 billion of the gross domestic product, and $34.8 billion in household income. (See the 2022 Pocket Guide to Ethanol.)
Equipment and Availability
Low-level blends of E10 or less require no special fueling equipment, and they can be used in any conventional gasoline vehicle.
It is also possible to accommodate blends above E10 in existing fueling equipment, however, some equipment needs to be upgraded to comply with federal code. See the Codes, Standards, and Safety page and the Handbook for Handling, Storing, and Dispensing E85 and Other Ethanol-Gasoline Blends for detailed information on compatible equipment.
FFVs (which can operate on E85, gasoline, or any blend of the two) are available as standard equipment with no incremental cost, making them an affordable alternative fuel vehicle option. However, recent changes in Corporate Average Fuel Economy credits for FFVs have resulted in reduced availability. Fueling stations offering E85 (flex fuel) are located in 43 states. Find ethanol (E85) fueling stations in your area.
Energy Security
The transportation sector accounts for approximately 30% of total U.S. energy needs and 70% of U.S. petroleum consumption. Using ethanol and other alternative fuels and advanced technologies to provide diverse clean transportation options strengthens national energy security by increasing resilience to natural disasters and fuel supply disruptions.
