Ethanol is a clear liquid with an agreeable odor that can be made
from natural products and is diluted with gasoline to provide a cleaner, more natural fuel source. It is a renewable fuel because it's made from plants. About 30% of all gasoline consumed the U.S. is blended with ethanol. There are three major types of ethanol: E95, E85, and E10. E95 is pure ethanol before it is denatured. Most vehicles cannot use this, so it must be mixed with gasoline first. E85 is the leading alternative fuel source in the U.S. It's a mixture of 85% ethanol and 15% gasoline. E10 is a combination of 10% ethanol and 90% gasoline and is the most common form currently used.
Ethanol is produced from crops such as corn, grain sorghum, sugar cane, wheat, and biomass. Biomass is agricultural wastes such as plant material left from logging or trash such as paper. Brazil, the world's largest producer of ethanol, makes it from sugar cane. The United States makes most of its ethanol from corn. The steps in producing ethanol are as follows: milling, liquefaction, saccharification, fermentation, distillation, dehydration, denaturing, and using the co-products.
Ethanol has both economical and environmental benefits. It moderates the price of gasoline to consumers because it takes some of the work away from the petroleum refining industry. It also creates many jobs because there are many steps in producing it. For example, many farmers are needed to grow the crops, and taxi drivers use the fuel to run their taxis. Ethanol also improves rural development because farmers must grow crops to make the fuel. Also, because ethanol is a natural product, it reduces air pollution so fewer toxins are released into the air. Therefore, smog problems in many major cities can be eliminated. Although ethanol can form explosive vapors in fuel tanks, it is safer than gasoline because its slow evaporation speed keeps alcohol concentration low and therefore non-explosive.
Many acres of cropland are needed to produce ethanol, and this makes it more expensive than gasoline. This can also be costly to the environment if the crops aren't replaced. Ethanol also gets less miles per gallon than the same amount of gasoline.