Ethanol, also known as ethyl alcohol or drinking alcohol, is a combustible clear liquid which is produced by the fermentation of sugars contained in crops such sugarcane, corn and soybeans. Ethanol shares similar properties to that of gasoline, and as such has evolved into a fuel substitute and fuel additive. The amount of ethanol contained in a fuel is usually indicated by the letter E, combined with a number, which signifies its concentration. E10 for instance, is 10 percent alcohol and 90 percent standard gasoline. E85, another common fuel, is 85 percent ethanol. E100 is pure ethanol.
Ethanol fuel is created by harvesting crops and allowing them to ferment, then distilling and dehydrating the liquid produced to get rid of the water it contains. Since most cars are designed to run on gasoline, ethanol is often blended with gasoline in ratios that allow normal cars to run. Most cars will accept E10 and many will accept E30. E85 requires vehicles be designed or specially outfitted to handle fuel with such ethanol concentration. When the price for oil was above $100 a barrel, high ethanol fuel cost considerably less per gallon than gasoline, and while the fuel efficiency of E85 is usually lower than gasoline, overall it cost less to drive on E85 than gasoline during that period.
Ethanol fuel is beneficial for several reasons. For one, it can cost less to drive on high ethanol fuel, when the price of oil is high. Secondly, ethanol is a renewable resource which reduces the need to import foreign oil. It also burns more cleanly than gasoline, so it is much better for the environment. On the downside, growing, tending and treating plants to create ethanol uses up considerable amounts of energy. By some estimates the amount of energy used to produce ethanol is greater than the amount of energy the ethanol ultimately ends up making when it is burned. Critics of ethanol believe that more efficient methods must be employed to make ethanol worthwhile, and are especially skeptical about corn as a source of ethanol, since other types of plants, like sugarcane and switch grass, can yield much greater amounts of biomass (and therefore ethanol) per acre.
