How Is Coal Changed Into Energy?
Coal, one of the fossil fuels, is a non-renewable source of energy. This means coal cannot be replenished as is the case with renewable energy sources, according to the United States Environmental Protection Agency (EPA). The process of turning coal into energy--typically electricity--is labor-intensive and dirty. Thanks to technological advances, though, the process is becoming cleaner from an environmental standpoint.
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Significance of Coal
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The American Coal Foundation (ACF) points out that 9 of every 10 tons of coal mined in the United States is used to produce electricity. More than 50 percent of electricity consumed in the U.S. comes from coal. Coal-generated electricity powers everything from heating and cooling to industries, such as health care and agriculture. The American Petroleum Institute (API) reports that the U.S. is a major exporter of coal to countries, such as Japan and Canada.
Recovering Coal
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API explains that coal is recovered from the earth through surface or deep mining. Surface mining is less expensive and tends to take place on flat land. Automation has taken some of the danger and health risks out of deep coal mining by aiding in the process of digging shafts and tunnels that provide access to coal. Once coal is accessed, the EPA notes that it must be transported to power plants where it is burned to form electricity.
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Turning Coal Into Electricity
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Turning coal into electricity is similar to the process of turning oil and natural gas into electricity, contends the ACF. First, a machine called a pulverizer breaks coal down into a fine powder. The powder, mixed with hot air, heads to a furnace. As the coal burns, it prompts water in a boiler to produce steam. This steam powers a turbine engine, which energizes a generator that converts mechanical energy into electric energy. A condenser then cools the steam, turning it back into water, at which point it goes back to the boiler to restart the process.
Turning Coal Into Gas Or Oil
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Though a relatively inefficient process, as of 2010, API states that coal can be turned into synthetic fuels. Coal can be made into a fuel similar to natural gas. It also can transform to a synthetic crude oil. The economic payoff for doing this, reports API, is not large enough for it to occur on a significant scale.
Environmental Considerations
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Burning coal produces several harmful pollutants, including carbon dioxide, sulfur dioxide, nitrogen oxides and mercury compounds. The EPA says that coal-fired burners must be equipped with devices that control the emissions. Mining, cleaning and transporting coal also carries environmental costs. The burning of coal generates waste, known as ash. The EPA estimates that about 10 percent of coal is ash. While industry disposes some of this waste into landfills, they often recycle a portion of it to produce products, such as cement and building materials.
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References
- Photo Credit glowing coal image by Georgios Alexandris from Fotolia.com
