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Ethanol Fuel

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other readings with assessment in Alternative Energy -- Wind Energy -- Geothermal Energy -- Hydropower -- Nuclear Energy --

see Alternative Energy Basics


 

ETHANOL MADE FROM CORN AND OTHER CROPS

Ethanol is a clear, colorless alcohol fuel made from the sugars found in grains, such as corn, sorghum, and wheat, as well as potato skins, rice, and yard clippings. Ethanol is a renewable fuel because it is made from plants. There are several ways to make ethanol from biomass. The most commonly used processes today use yeast to ferment the sugars and starch in corn. Corn is the main ingredient for ethanol in the United States due to its abundance and low price. Most ethanol is produced in the corn-growing states in the Midwest. The starch in the corn is fermented into sugar, which is then fermented into alcohol. Other crops such as, barley, wheat, rice, sorghum, sunflower, potatoes, sugar cane and sugar beets can also be used to produce ethanol.

Sugar cane and sugar beets are the most common ingredients for ethanol in other parts of the world. Since alcohol is created by fermenting sugar, sugar crops are the easiest ingredients to convert into alcohol. Brazil, the country with the world's largest ethanol production, makes most of its ethanol this way. Today, many cars in Brazil operate on ethanol made from sugar cane.

A new experimental process which breaks down cellulose in woody fibers, is called "cellulosic ethanol". With this process we can make ethanol from trees, grasses, and crop wastes. Trees and grasses need less energy than grains, which must be replanted every year. Scientists have developed fast-growing trees that grow to size in ten years. Many grasses can produce two harvests a year for many years. Someday, you may find yourself driving by huge farms that are not producing food or animal feed, but feedstock for ethanol. Feedstock is the raw material used to make a product.

HISTORY OF ETHANOL

Ethanol is not a new fuel. In the 1850s, ethanol was a major lighting fuel. During the Civil War, a liquor tax was placed on ethanol to raise money for the war. The tax increased the price of ethanol so much that it could no longer compete with other fuels such as kerosene in lighting devices. Ethanol production declined sharply because of this tax and production levels did not begin to recover until the tax was repealed in 1906.

In 1908, Henry Ford designed his Model T to run on a mixture of gasoline and alcohol, calling it the fuel of the future. In 1919, when Prohibition began, ethanol was banned because it was considered a liquor. It could only be sold when it was mixed with petroleum. With the end of Prohibition in 1933, ethanol was used as a fuel again. Ethanol use increased temporarily during World War II when oil and other resources were scarce. In the 1970s, interest in ethanol as a transportation fuel was revived when embargoes by major oil producing countries cut gasoline supplies. Since that time ethanol use has been encouraged by offering tax benefits for producing ethanol and for blending ethanol into gasoline. In 1988, ethanol began to be added to gasoline for the purpose of reducing carbon monoxide emissions. Learn more about the history of ethanol in a timeline.

ETHANOL AS A TRANPSORTATION FUEL

As a transportation fuel, ethanol can be used as a total or partial replacement for gasoline. Gasoline containing ten percent ethanol - E10 - is used in many urban areas that don't meet clean air standards. Some states promote more widespread use of E10. Minnesota, for example, requires almost all gasoline sold in the state to contain 10 percent ethanol. All vehicles that run on gasoline can use E10 without making changes to their engines. Over 99 percent of the ethanol produced in the United States is mixed with gasoline to make E-10.

E85 is an alternative fuel that is 85 percent ethanol and 15 percent gasoline, used mainly in the Midwest and South. Vehicles are not modified to run on E85; they are specially manufactured as flexible fuel vehicles (FFV). Flexible Fuel Vehicles can use any mixture of ethanol and gasoline up to E85. There are about 146,000 cars and trucks using E85. Most of these are fleet vehicles.

Ethanol and the Environment

Using ethanol means that we use a little bit less oil (a nonrenewable fuel) to make gasoline.  Unlike gasoline, ethanol is nontoxic (safe to handle) and biodegradable, it quickly breaks down into harmless substances if spilled. When small amounts of ethanol are added to gasoline, usually less than 10 percent, there are many advantages. Ethanol reduces carbon monoxide and other toxic pollution from the tailpipes of vehicles, making the air cleaner. It keeps engines running smoothly without the need for lead or other chemical additives. Because ethanol is made from crops that absorb carbon dioxide and give off oxygen, it has the potential to reduce greenhouse gas emissions and help maintain the balance of carbon dioxide in the atmosphere. This process is called the carbon cycle.



Last Revised: October 2007
Sources: Energy Information Administration, Annual Energy Review 2006, June 2007.
The National Energy Education Development Project, Alternative Fuels: What Car Will You Drive?, 2007.
U.S. Department of Energy, Energy Efficiency and Renewable Energy, Clean Cities Fact Sheet- Low Level Ethanol Fuel Blends April 2005

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