Coal is fossil fuel or fuel that comes from the remains of prehistoric plants or animals. The formation of coal occurs over millions of years via a process known as carbonation. Coal is a typical conventional solid fuel that has been exploited as an important source of fuel.
The main use of coal is as fuel for electric power plants for which more than 50% of the coal produced in the world is used, the simplest use of coal is to burn it for heat. Other uses of coal that may be increasingly important in the future are in the production of liquid fuel by direct or indirect liquefaction to replace fuels made from petroleum, production of methanol a possible substitute for gasoline and production of synthetic gases.