The United States became the world's largest producer of ethanol fuel in 2005. The U.S. produced 15.8 billion U.S. liquid gallons of ethanol fuel in 2019, and 13.9 billion U.S. liquid gallons (52.6 billion liters) in 2011, an increase from 13.2 billion U.S. liquid gallons (49.2 billion liters) in 2010, and up from 1.63 billion gallons in 2000. Brazil and U.S. production accounted for 87.1% of global production in 2011. In the U.S, ethanol fuel is mainly used as an oxygenate in gasoline in the form of low-level blends up to 10 percent, and, increasingly, as E85 fuel for flex-fuel vehicles. The U.S. government subsidizes ethanol production.
The ethanol market share in the U.S. gasoline supply grew by volume from just over 1 percent in 2000 to more than 3 percent in 2006 to 10 percent in 2011. Domestic production capacity increased fifteen times after 1990, from 900 million US gallons to 1.63 billion US gal in 2000, to 13.5 billion US gallons in 2010. The Renewable Fuels Association reported 209 ethanol distilleries in operation located in 29 states in 2011.
By 2011 most cars on U.S. roads could run on blends of up to 10% ethanol(E10), and manufacturers had begun producing vehicles designed for much higher percentages. However, the fuel systems of cars, trucks, and motorcycles sold before the ethanol mandate may suffer substantial damage from the use of 10% ethanol blends. Flexible-fuel cars, trucks, and minivans use gasoline/ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By early 2013 there were around 11 million E85-capable vehicles on U.S. roads. Regular use of E85 is low due to lack of fueling infrastructure, but is common in the Midwest. In January 2011 the U.S. Environmental Protection Agency (EPA) granted a waiver to allow up to 15% of ethanol blended with gasoline (E15) to be sold only for cars and light pickup trucks with a model year of 2001 or later. The EPA waiver authorizes, but does not require stations to offer E15. Like the limitations suffered by sales of E85, commercialization of E15 is constrained by the lack of infrastructure as most fuel stations do not have enough pumps to offer the new E15 blend, few existing pumps are certified to dispense E15, and no dedicated tanks are readily available to store E15.
Historically most U.S. ethanol has come from corn, and the required electricity for many distilleries came mainly from coal. There is a debate about ethanol's sustainability and environmental impact. The primary issues related to the large amount of arable land required for crops and ethanol production's impact on grain supply, indirect land use change (ILUC) effects, as well as issues regarding its energy balance and carbon intensity considering its full life cycle.
History
In 1826 Samuel Morey experimented with an internal combustion chemical mixture that used ethanol (combined with turpentine and ambient air then vaporized) as fuel. At the time, his discovery was overlooked, mostly due to the success of steam power. Ethanol fuel received little attention until 1860 when Nicholas Otto began experimenting with internal combustion engines. In 1859, oil was found in Pennsylvania, which decades later provided a new kind of fuel. A popular fuel in the U.S. before petroleum was a blend of alcohol and turpentine called "camphene", also known as "burning fluid". The discovery of a ready supply of oil and unfavorable taxation on burning fluid made kerosene a more popular fuel.
In 1896, Henry Ford designed his first car, the "Quadricycle" to run on pure ethanol. In 1908, the revolutionary Ford Model T was capable of running on gasoline, ethanol or a combination. Ford continued to advocate for ethanol fuel even during the prohibition, but lower prices caused gasoline to prevail.
Gasoline containing up to 10% ethanol began a decades-long growth in the United States in the late 1970s. The demand for ethanol produced from field corn was spurred by the discovery that methyl tertiary butyl ether (MTBE) was contaminating groundwater. MTBE's use as an oxygenate additive was widespread due to mandates in the Clean Air Act amendments of 1992 to reduce carbon monoxide emissions. MTBE in gasoline had been banned in almost 20 states by 2006. Suppliers were concerned about potential litigation and a 2005 court decision denying legal protection for MTBE. MTBE's fall from grace opened a new market for ethanol, its primary substitute. Corn prices at the time were around US$2 a bushel. Farmers saw a new market and increased production. This demand shift took place at a time when oil prices were rising.