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.
FAQs
Because of its high oxygen content, ethanol burns more completely than ordinary unleaded gasoline and reduces harmful tailpipe emissions. Ethanol prevents gas line freeze-up. It suspends moisture in your fuel system, so you don't need to add expensive anti-freeze in cold weather.
What are the benefits of alternative fuels? ›
AFVs produce lower emissions and fewer toxic contaminants than gasoline and diesel vehicles. Alternative fuel vehicles have inherently lower harmful emissions, including toxic contaminants, compared to gasoline and diesel vehicles. In particular, evaporative and start emissions are significantly reduced.
What are the major challenges facing implementation of ethanol as a fuel? ›
Higher-ethanol blends still produce significant levels of air pollution, reduce fuel efficiency, jack up corn and other food prices, and have been treated with skepticism by some car manufacturers for the damage they do to engines. Growing corn to run our cars was a bad idea 10 years ago.
What is the pros and cons of ethanol? ›
Ethanol has both pros and cons as a renewable fuel source. While it is renewable, domestically produced, and produces fewer greenhouse gas emissions than non-renewable sources of energy, it is less energy-dense, expensive to produce, and can have negative impacts on the environment.
What are two advantages and two disadvantages of ethanol? ›
Proponents of ethanol ethanol argue that it is one of the alternative fuels and it is a cleaner, more sustainable alternative to fossil fuels. In contrast, critics argue that it is not a viable solution for reducing greenhouse gas emissions and may contribute to environmental problems.
What are the environmental benefits of ethanol? ›
Ethanol reduces tailpipe carbon monoxide (CO) emissions by as much as 30%, toxics content by 13% (mass) and 21% (potency) and tailpipe fine particulate matter (PM) emissions by 50%.
What are the negative effects of ethanol? ›
Chronic ingestion of ethanol may cause liver cirrhosis, affect the nervous system and affect the glands in humans. Ethanol may cause mutations (genetic changes). Ethanol is rapidly oxidised by the body to carbon dioxide and water, with no cumulative effect.
What are 3 benefits of alternative energy? ›
Benefits of Renewable Energy
Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution. Diversifying energy supply and reducing dependence on imported fuels. Creating economic development and jobs in manufacturing, installation, and more.
How can alternative fuels help the environment? ›
Using biodiesel reduces life cycle emissions because carbon dioxide released from biodiesel combustion is offset by the carbon dioxide absorbed from growing soybeans or other feedstocks used to produce the fuel.
What positive impact do alternative fuels have on the environment? ›
Compared to fossil fuels like oil and coal, they emit fewer greenhouse gases, which helps combat climate change. For example, biofuels can reduce emissions by up to 60%.
Using higher amounts of ethanol reduces fuel economy. There would have to be a large infrastructure change to provide ethanol refueling stations. Ethanol also absorbs water easily giving it a high tendency to corrode materials.
Is ethanol really better for the environment? ›
Today's corn-based ethanol reduces greenhouse gas (GHG) emissions by roughly 40 – 50 percent compared to regular gasoline, according to recent studies by Harvard, USDA and the Department of Energy's Argonne National Laboratory.
Is ethanol good or bad? ›
It burns cleaner and as a result produces less pollution. Given the environmental concerns facing our population, this can only be considered a good thing.
What are the advantages of alcohol as a fuel? ›
Alcohols burn more completely then petroleum- based fuels, thus increasing combustion efficiency. Advantages of mixing alcohol with gasoline are that alcohol tends to increase the octane rating and reduce carbon monoxide and other tailpipe emissions.
What are the advantages of using alcohol as fuel? ›
Advantages of fuel blends are that alcohol tends to increase the octane rating and reduce carbon monoxide (CO) and other tailpipe emissions from the engine. The octane number of a fuel indicates its resistance to knock (abnormal combustion in the cylinder).
What are the advantages of making ethanol? ›
What are the advantages of producing ethanol by fermentation? The reaction takes place at about 30°C and atmospheric pressure. This requires very little energy and is therefore cheap. As plants are used to provide the glucose, the process is carbon neutral.
Why is ethanol a better fuel than hydrogen? ›
“Ethanol is a clean and safe biofuel in the liquid phase, which is much easier and safer for storage and transport than pure hydrogen.
