Electricity Education - Coal
Formation of Coal
Coal, a combustible mineral, began to form about 300 million years ago when large plants died. Throughout time, these plants were buried underneath vast amounts of water and dirt. The continuous pressure caused by the overlaying material along with periods of extreme heat created this mineral.
Coal is considered a "non-renewable" resource, because it takes so log to form. It is mainly located in three large regions in the United States: the Appalachian Coal Region, the Interior Coal Region and the Western Coal Region. The Western Coal mines are the largest in the world. Coal was first discovered in Virginia in 1701, but mining production did not begin until 1748.
There are four basic varieties of coal: anthracite, bituminous, sub-bituminous and lignite. Anthracite has the highest energy content with an average of 25 million British Thermal Units (Btu) per ton of coal. Lignite only averages 14 million Btu per ton. A Btu is a measurement of energy. It is the amount of energy needed in order to raise the temperature of 1 pound of water 1 degree Fahrenheit at a temperature of 39.2 degrees Fahrenheit.
Uses of Coal
The four major uses of coal mined in the U.S. are electric power generation, industrial use, steel making, and export to other countries. It is estimated that more than 90% of all the coal mined in the United States is used to generate electricity. Roughly 52% of the electricity generated in the U.S. comes from burning of coal. Coal is such a great resource because it is the cheapest source of power per million Btu. It costs less then half the price of natural gas and petroleum. The United States is the 4th largest coal exporter in the world, sending approximately 60 million tons of coal to other countries annually, at a price of close to $2 billion. Coal generates about 40% of the total energy consumed worldwide.
See a Macromedia Flash Animation of how a Coal Power Plant Works
Tons and Tons of Coal
The United States produces more than a billion short tons of coal each year. Roughly 85% of the known US fossil fuels remaining in this country are coal; which is nearly 275 billion short tons of future recoverable coal. If current consumption levels continue, the US has more than 250 years of supply. Currently, Wyoming is the largest coal producing state in the country, producing close to 340 million short tons per year. Coal ranks third of all fuel and non-fuel commodities mined today behind crushed stone, and sand and gravel.
How do we get it?
Coal is mined from the surface of the earth, as well as from underground. Approximately 70% of all coal comes from surface operations. Once mined and processed, coal travels by trains, ships, barges, trucks and slurry pumps to its final destination. Railroads transport more coal then any other commodity--about 70% of all coal shipments.
Coal: Yesterday, Today and Tomorrow
For many years coal mining was known as a destructive assault on the environment and an extremely dangerous occupation. Over the past 30 years, however, many precautionary measures have been taken in attempts to preserve the environment and promote a safe working environment.
Technology advances have enabled coal to burn more efficiently with reduced sulfur and nitrogen oxide emissions. For instance, even with electricity demand up 124% since 1970, the United States Environmental Protection Agency (EPA) reports that harmful emissions have been lowered by 33% and expectations of lowering emissions by 47% by 2015 are not out of the question.
Currently, over 120,000 people are employed in the coal industry in the US. Even though more coal is being mined per coal miner per hour, a lower rate of nonfatal injuries and illnesses is being reported. In 2001, mining accounted for 2.1% of all fatal injuries in the United States. This percentage is down substantially from the 1970s.
The American Coal Foundation (ACF) provides standards-based lesson plans and other information for teachers about coal -- its formation, production and use. ACF is a 501(c)(3) organization and does not engage in lobbying.