Introduction
Coal power is the safest, most efficient, and cheapest way to produce electricity in large quantities. This fossil fuel powers about 48% of America's electrical grid. It is formed by dead plant and animal matter, and is a biofuel. Coal has many forms some which are used in power plants and others like graphite which are used in pencils; graphite is commonly mistaken for lead.
Clean Coal Technology (CCT) is being introduced into our world, the only emissions that will come from these plants will be carbon dioxide and water vapor. CCT will produce many more megawatt hours and will be the leading energy source in countries like China, India, and America.
Formation
Coal is formed by dead plant and animal matter, therefore it is a bio-fuel. The start of formation occurs when a plant or animal dies, is decomposed and is buried under sediment. Coal forms in swampy or muddy areas because the mud and water in these areas saves the former animal matter from oxidification. Over millions of years the matter is compressed forming peat. Peat is not exactly coal yet, before becoming coal the peat will be further compressed and cooked by the Earth's pressure. Over several more million years the peat is compressed deep below the Earth's surface until it becomes coal.
Mining and Burning
Before coal can be of any use to humans it must be mined out of the ground. Coal is mined through several different processes; the easiest is open-pit mining which means that the coal is found at the surface and can be easily mined with tractors and cranes. Open-pit mining accounts for most of the mines in the world. Other processes of coal mining occur below the surface of the Earth where methods of mining such as long wall mining, continuous mining, blast mining, short wall mining, and the most dangerous form, retreat mining.
Coal is burned in power plants to generate electricity. The coal falls onto a conveyor then into a coal hopper. From there the coal falls into a coal pulverization mashine or smasher which grinds it into smaller pieces. It is then burned, heating metal pipes filled with water. The water boils into steam and is then transferred to electric generators where it spins a magnet between copper coils, creating an electric current. Steam from this process follows a series of pipes to a cooling tower where it is converted back to water and pumped back to the furnace. The emissions of burning coal are highly toxic and have caused pollution problems in places like China. Emissions from coal plants must be treated before exiting the exhaust pipe. The exhaust has a lot of sulfur dioxide and particulate matter in it, which is converted to carbon dioxide by calcium carbonate and can be expressed through the chemical equation:
CaCO3 + SO2 Yields CaSO3 + CO2
As you can see utilization of this process yields carbon dioxide a clean greenhouse gas and promotes plant growth on our planet; the other product is a solid, calcium sulfate. Calcium sulfate can be further oxidized to form gypsum. This process is called flue gas desulfurization and is used in CCT. China plans to reduce its sulfur dioxide emissions by 61.4% by using this process. Coal plants also must eliminate particulate matter emissions. This can be achieved by using venturi scrubbers, cyclones, or packed towers; these are other forms of scrubbing technology.