Ethanol Facts: Environment
Ethanol is one of the best tools we have to fight air pollution from vehicles. And there is no fuel available at scale today that matches ethanol's ability to improve overall environmental quality compared to gasoline. From its biodegradable nature to reductions in greenhouse gas and tailpipe emissions, ethanol provides a tool to address environmental concerns without requiring an entirely new way for goods and people to get from one place to another.
Ethanol contains 35% oxygen. Adding oxygen to fuel results in more complete fuel combustion, reducing harmful tailpipe emissions. Ethanol also displaces the use of toxic gasoline components such as benzene, a carcinogen. Ethanol is non-toxic, water soluble and quickly biodegradable. Ethanol is a renewable fuel produced from plants, unlike petroleum-based fossil fuels that have a limited supply and are the major contributor of carbon dioxide (CO2) emissions, a greenhouse gas (GHG).
FACT: Using ethanol in place of gasoline helps to reduce carbon dioxide (CO2) emissions by up to 29% given today's technology.
Because ethanol is made from renewable, plant-based feedstocks, the CO2 released during a vehicle's fuel combustion is "recycled" during the growth of ethanol feedstocks. Independent analyses comparing ethanol and gasoline show ethanol reduces GHG emissions from 30-50%. A study published by Yale University's Journal of Industrial Ecology found that GHG emissions from ethanol produced at modern dry-mill facilities are "... equivalent to a 48 percent to 59 percent reduction compared to gasoline, a twofold to threefold greater reduction than reported in previous studies." New technologies, additional feedstocks, and higher blends of ethanol including E85 all promise greater C02 reductions.
FACT: In 2010, the production and use of 13 billion gallons of ethanol in the U.S. reduced CO2-equivalent greenhouse gas emissions by 21.9 million tons, the equivalent to removing 3.5 million cars and pickups from America's roadways. (Source: Argonne National Laboratory's GREET Model).
FACT: New technologies are increasing ethanol yields, improving efficiencies and allowing ethanol biorefineries to make better use of natural resources. According to May 2010 research on ethanol production resource requirements in 2008 from the University of Illinois at Chicago, energy requirements for ethanol production have decreased 28% since 2001, electricity demands by 32%, and water use is down to 2.72 gallons per gallon of ethanol produced. All of these improvements were achieved while ethanol yields increased by 5.3%.
FACT: Ethanol requires less fossil fuel inputs than gasoline refining. According to the University of California at Berkeley, the production of 19 units of ethanol energy takes just one unit of petroleum energy. An analysis released in June 2010 by the U.S. Department of Agriculture concluded that one unit of fossil energy used in producing grain-based ethanol results in 2.3 units of energy in the form of ethanol. Researchers at the Department of Energy's Argonne National Laboratory found that it takes 1.23 units of fossil energy to produce one unit of energy in the form of gasoline.
FACT: The American Lung Association in Illinois supports the use of E85, a blend of 85% ethanol and 15% gasoline for flex-fuel vehicles specifically designed to operate on this fuel. "E85 vehicles are required to meet the same tailpipe emission standards as other light duty vehicles, however, when using E85, these flex-fuel vehicles may have lower emissions of some pollutants than conventional gasoline-fueled vehicles.”
FACT: Ethanol reduces tailpipe carbon monoxide emissions by as much as 30%, toxics content by 13% (mass) and 21% (potency), and tailpipe fine particulate matter (PM) emissions by 50%. Ethanol also reduces secondary PM formation by diluting aromatic content in gasoline. Over half of the air pollution attributable to vehicles comes from "high emitting" vehicles that make up only 10% of the vehicle fleet. High emitters include older vehicles as well as well as newer cars with malfunctioning pollution control systems. The use of ethanol-blended fuel is also one of the best pollution control strategies for off-road vehicles, including motorcycles, ATVs and snowmobiles, which represent a significant source of emissions. Source: Smog Reyes, February 2004.
FACT: Ethanol is the oxygenate of choice in the federal winter oxygenated fuels program in cities that exceed public health standards for carbon monoxide pollution.
FACT: Ethanol is rapidly biodegraded in surface water, groundwater and soil, and is the safest component in gasoline today.
A study conducted for the Governors' Ethanol Coalition, "The Fate and Transport of Ethanol-Blended Gasoline in the Environment," concluded that ethanol poses no threat to surface water and ground water. According to the report, ethanol is a naturally occurring substance produced during the fermentation of organic matter and is expected to rapidly biodegrade in essentially all environments. When gasoline contaminates soil or water, ethanol is the first component to quickly, safely, and naturally biodegrade. A study commissioned by the MTBE industry suggested that in the event of a gasoline spill or leak, since ethanol breaks down first, benzene would persist in the environment longer. But this ignores the fact that ethanol-blended fuels contain less benzene, and the real threat posed to the environment is from the presence of benzene in gasoline, not ethanol.
FACT: Ethanol reduces smog pollution.
Blending ethanol in gasoline dramatically reduces carbon monoxide tailpipe emissions. According to the National Research Council, carbon monoxide emissions are responsible for as much as 20% of smog formation. Additionally, ethanol-blended fuels reduce tailpipe emissions of volatile organic compounds, which readily form ozone in the atmosphere. These reductions more than offset any slight increases of evaporative emissions due to the higher volatility of ethanol-blended fuel. Thus, the use of ethanol plays an important role in smog reduction.
Importantly, in reformulated gasoline areas where smog is of most concern, gasoline blended with ethanol must meet the same evaporative emission standard as gasoline without ethanol. These ethanol blends have the added benefit of providing reduced tailpipe carbon monoxide emissions and, therefore, further emissions reductions of smog.
FACT: Ethanol has a positive energy balance.
Whether produced from corn or other biomass feedstocks, ethanol generates more energy than used during production. Plants used in ethanol production harness the power of the sun to grow. By releasing the energy stored in corn and other feedstocks, ethanol production utilizes solar energy, replacing fossil energy use. A life cycle analysis of ethanol production - from the field to the vehicle - found that ethanol has a large and growing positive fossil energy balance. According to a 2008 U.S. Department of Agriculture Study, each gallon of corn ethanol today delivers as much as 2.3 times more energy than was used to produce it. Significant energy efficiency improvements have been made in ethanol production due to higher yielding corn varieties, technological advances in ethanol production such as the use of molecular sieves and natural gas, and improved farming practices (precision and no-till farming.)
According to a University of California-Berkeley study, "Ethanol Can Contribute to Energy and Environmental Goals," the production of ethanol reduces petroleum use 95% as compared to gasoline refining.
Unlike ethanol, other fuels, including MTBE and gasoline, take more fossil energy to produce than they yield. Importantly, producing ethanol from domestic grains achieves a net gain in a more desirable form of energy. It utilizes abundant domestic energy sources, such as natural gas and coal, to convert grain into a premium liquid fuel. Only about 17% of the energy used to produce ethanol comes from liquid fuels, such as gasoline and diesel fuel.
FACT: Water usage in ethanol production is declining.
Water is required to produce most of the energy we consume. For example, a gallon of gasoline requires anywhere from 2.5-8 gallons of water to produce. The use of all natural resources, including water, in ethanol production is an issue the U.S. ethanol industry takes very seriously. That is why ethanol producers are researching ways to reduce water use. Those efforts are paying off. According to survey data compiled by the U.S. Department of Energy's Argonne National Laboratory, water consumption at America's ethanol biorefineries decreased 26.6% from 2001 to 2006. A new study from the University of Illinois-Chicago finds that, on average, a dry-mill corn ethanol plant in 2008 uses 2.72 gallons of water per anhydrous gallon of ethanol produced and discharges 0.46 gallons of water per anhydrous gallon of ethanol. We invite you to view "Water Facts" published by the U.S. Geological Survey for interesting water statistics.
