Since the mid 1970’s, the predominant motor vehicle fuel in the United States has been unleaded gasoline. By the 1980’s, it was no longer the only type of gasoline available. Ethanol fuel – which is also referred to as Gasohol in the United States, is offered for sale as motor vehicle fuel in two blends – E10 (90 percent regular unleaded gasoline/10 percent ethanol) and E85 (85 percent ethanol/15 percent regular unleaded gasoline). E10 blends can be run in vehicles that use unleaded gasoline with no modifications to the fuel system. However, E85 does require vehicles that are equipped to be “Flex Fuel” capable, due to E85’s corrosive properties.
What it is – Also known as ethyl alcohol, ethanol is produced by the fermentation of sugars by yeasts, and is the principal type of alcohol found in alcoholic beverages. Ethanol is a volatile, flammable, and colorless liquid with a strong chemical odor. Ethanol produced in the United States is largely produced from corn. Currently, the first generation processes for the production of ethanol from corn use only a small part of the corn plant: the kernels are taken from the plant and only the starch, which represents about 50% of the dry kernel mass, is transformed into ethanol. The largest single use of ethanol is as a motor fuel and fuel additive. Other applications include use as a solvent, an antiseptic, and as the active fluid in modern (post-mercury) thermometers.
What is does – According to an industry advocacy group called the American Coalition for Ethanol, ethanol as a fuel reduces harmful tailpipe emissions of carbon monoxide, particulate matter, oxides of nitrogen, and other ozone-forming pollutants.
Ethanol is increasingly used as an oxygenate additive for standard gasoline, as a replacement for methyl t-butyl ether (MTBE), the latter chemical being responsible for considerable groundwater and soil contamination. Argonne National Laboratory analyzed the greenhouse gas emissions of many different engine and fuel combinations. Comparing ethanol blends with gasoline alone, they showed reduction of 17% with the conventional E85 ethanol blend.
Why Ethanol? – Ethanol is used in California Cleaner Burning Gasoline and the reformulated gasoline required in many of the major metropolitan areas of the country. In addition, to meet the Renewable Fuels Standard included as part of the Energy Independence and Security Act of 2007, gasoline/ethanol blends have been introduced to the rest of the country.
According to YES magazine, the United States used 4.7 billion bushels of corn (40% of the harvest) to produce over 13 billion gallons of ethanol fuel in 2013.