About 92 percent of the coal used in the United States, is for generating electricity. Except for a small amount of net exports, the rest of the coal is used, as a basic energy source in many industries, including, steel, cement and paper.
The four major uses of coal are: 
FOR ELECTRIC POWER
Coal is used to generate roughly half of all electricity produced in the United States. Besides electric utility companies, industries and businesses with their own power plants use coal to generate electricity. Power plants burn coal to make steam. The steam turns turbines which generate electricity.
FOR INDUSTRY
A variety of industries use coal's heat and by-products. Separated ingredients of coal (such as methanol and ethylene) are used in making plastics, tar, synthetic fibers, fertilizers, and medicines. The concrete and paper industries also burn large amounts of coal.
FOR MAKING STEEL
Coal is baked in hot furnaces to make coke, which is used to smelt iron ore into iron needed for making steel. It is the very high temperatures created from the use of coke that gives steel the strength and flexibility for products such as bridges, buildings, and automobiles.
FOR EXPORT
In 2005, 49.9 million short tons, or about four percent of the coal mined, was exported to other countries from the United States. Coal is exported to many different countries, but most trade is with Canada, Brazil, the Netherlands, and Italy. More than half of coal exports are used for making steel.
Coal exports have been generally shrinking in the past 10 years, while the amount of coal imported from other countries has been growing. In 2005, about 30.5 million short tons of coal were imported from other countries. Most of these imports (from Colombia, Venezuela, and Indonesia) were shipped to electric power producers along the U.S. coastlines.
Environmental laws and modern technologies have greatly reduced coal's impact on the environment. Without proper care, mining can destroy land and pollute water. Today, restoring the land damaged by surface mining is an important part of the mining process. Because mining activities often come into contact with water resources, coal producers must also go to great efforts to prevent damage to ground and surface waters.
When coal is burned as fuel, it gives off carbon dioxide, the main greenhouse gas that is linked with global warming. Burning coal also produces emissions, such as sulfur, nitrogen oxide (NOx), and mercury, that can pollute the air and water. Sulfur mixes with oxygen to form sulfur dioxide (SO2), a chemical that can affect trees and water when it combines with moisture to produce acid rain. Emissions of nitrogen oxide help create smog, and also contribute to acid rain. Mercury that is released into the air eventually settles in water. The mercury in the water can build up in fish and shellfish, and can be harmful to animals and people who eat them. The Clean Air Act and the Clean Water Act require industries to reduce pollutants released into the air and the water.
The coal industry has found several ways to reduce sulfur, nitrogen oxides, and other impurities from coal. They have found more effective ways of cleaning coal before it leaves the mine, and coal companies look for low-sulfur coal to mine. Power plants use "scrubbers" to clean sulfur from the smoke before it leaves their smokestacks. In addition, industry and government have cooperated to develop "clean coal technologies" that either remove sulfur and nitrogen oxides from coal, or convert coal to a gas or liquid fuel. The scrubbers and NOx removal equipment are also able to reduce mercury emissions from some types of coal. Scientists are working on new ways to reduce mercury emissions from coal-burning power plants, since the Environmental Protection Agency (EPA) has set tighter mercury limits for the future.
Information taken directly from the Energy Information Administration.
