Coal reserves exist in every country in the world and on every continent except Antarctica. According to the World Coal Association, there are enough coal reserves to meet current demand for 112 years, but only enough oil and gas reserves to meet current demand for the next 46 and 54 years, respectively.
Coal is a mineral consisting of fossilized carbon. It is a black or brownish-black sedimentary rock that burns. Normally coal is found between layers of other sedimentary rock in veins geologists call coal streams or coal beds. Exposure to heat and pressure through metamorphic processes converts soft coal into harder forms, including anthracite coal. The primary ingredient in coal is carbon; it also includes small quantities of other elements, including sulfur, hydrogen, nitrogen and oxygen.
Coal is an important energy resource. Historically, its use was to provide heat for homes and businesses as well as for industrial purposes, such as metal refining. However, it has grown to be the primary fuel used in the production of electricity.
The formation of coal begins when dead plant material turns into peat. As peat is buried under other layers of sediment, the pressure converts it to lignite, and then to sub-bituminous coal before it becomes anthracite; these biological and geological processes take eons to complete.