All About Coal and Electricity - Accent Energy, NY
Many people think they only use coal on beautiful summer days when they pour briquettes into their barbecue grill. While your char-broiled burger might be the most delicious way to use coal, it's by no means the most important. Coal, a simple combustible rock, is a big contributor to the American way of life. Plentiful and (relatively) inexpensive, coal is very important in industrial and residential applications.
Like other fossil fuels (petroleum and natural gas), it takes a lot of time for coal to form. Coal starts out as peat: wet plant matter that is partially decayed. You can find peat in wetlands, bogs, swamps and other places; anywhere you can find water and dead plants. Buried by sediment, attacked by bacteria, the peat gradually dries out in the oxygen-deprived environment. After millions of years of pressure and heat, the peat becomes carbon-rich coal.
There are several different kinds of coal, and each kind has advantages and disadvantages. Many human cultures have simply used peat to heat their dwellings and cook their food. The youngest kind of coal is called lignite. Still soft and brown, it's not as compressed as it will be in the future. As a result of its lower carbon content, lignite is considered a lower-rank coal but can still be used in electricity generation. The next kind of coal is sub-bituminous, which is firmer and darker. After still more time and pressure, you get bituminous coal, which often features striated layers of different-colored material. Anthracite coal is very dark, shiny and hard, and is often used to heat commercial and residential structures. The last, and highest, grade of coal is called graphite. Yes, this is the material used in pencils.
Today, lots of talk centers around the increasing scarcity of petroleum. Fortunately, coal is quite plentiful around the world, and the United States has a ready supply that will last a long time. Particularly large deposits can be found in the Appalachian region, the Midwest and the Dakotas. There is also a great deal of coal in Central New York. In 2007, over 1.1 billion short tons of coal were removed from American mines, including 42 million from Texan mines. (391 million short tons were recovered from the Appalachian region and 619 million short tons were recovered from the West.) While the United States imported 36 million short tons of coal, it exported 59 million short tons, representing a bright spot in American energy independence.
Before coal can be used, of course, it must be extracted from the earth. Miners can use a couple different options to do this. If the coal is close to the surface, the top layers of the landscape can simply be removed, allowing access to the coal. For coal that is trapped further down, miners must dig deep shafts to provide access. Some currently operating American mines operate at depths up to 500 feet. Underground coal mining is dangerous, but advances in engineering and safety technology have improved matters. In addition to the main shaft, additional holes are drilled into the earth to provide ventilation, thereby ensuring miners have the fresh air they need. Coal is removed from underground seams with hand and power tools and broken into pieces small enough to be carried up the main shaft on a conveyor belt. Once the coal is above ground, it is sent to its destination by rail, truck or ship.
Where does all of this coal go? You may be surprised to learn that half of all of the electricity in the American power grid is generated by coal-burning power plants. To make the electricity, coal is pulverized into a fine powder and is then blown into a large boiler surrounded by pipes filled with water. This coal powder is burned at 2500 degrees Fahrenheit, which turns the liquid water into high-pressure steam. Thanks to this high pressure, the steam flows quickly through a turbine. A turbine is basically a propeller wrapped around a big magnet. Using the properties of electromagnetism, electricity is generated and wired to transformers that send it out to your home. The smokestacks on a coal-burning power plant release very little solid material. Recent technological advances have resulted in smokestack scrubbers that can severely reduce the amount of harmful gases released from a plant. Coal is also widely used to keep industrial plants running; after all, it takes a lot of energy to make steel.
Coal is powerful, plentiful and reasonably priced, making it an important part of the United States' energy equation for decades, if not centuries, to come.