Coal is a sedimentary rock composed primarily of carbon, hydrogen, and oxygen. Coal is a fossil fuel formed from ancient plants buried deep in the Earth's crust over 300 million years ago. Historians believe coal was first used commercially in China for smelting copper and for casting coins around 1,000 BC. Almost 92% of all coal consumed in the U.S. is burned by electric power plants, and coal accounts for about 55% of total electricity output. Coal is also used in the manufacture of steel. The steel industry first converts coal into coke, then combines the coke with iron ore and limestone, and finally heats the mixture to produce iron. Other industries use coal to make fertilizers, solvents, medicine, pesticides, and synthetic fuels.
There are four types of mined coal: anthracite (used in high-grade steel production), bituminous (used for electricity generation and for making coke), sub-bituminous, and lignite (both used primarily for electricity generation).
Coal futures trade at the New York Mercantile Exchange (NYMEX). The contract trades in units of 1,550 tons and is priced in terms of dollars and cents per short ton.
Supply - U.S. production of bituminous coal in 2007 (annualized through Dec) fell -1.37% yr/yr to 1.146 tons, down from the 2006 record high of 1.162 billion tons.
Demand - U.S. consumption of coal in 2006 (latest data available) fell by -1.00% to 1.114 billion tons, down from the 2006 record high of 1.125 billion tons.
Trade - U.S. exports of coal in 2006 (latest data available) fell -0.59% yr/yr to 49.647 million tons, and imports rose +19.0% yr/yr to 36.246 million tons. The major exporting destinations for the U.S. are Canada and Europe.