For information on the availability of fuels, their effect on the environment, and alternative energy sources, see Energy supply and Environmental pollution . Solid fuels Coal is used chiefly to produce electricity. It is burned to create heat to turn water into steam. Some coal is made into coke, a charcoallike solid that is an essential raw material in the production of iron and steel. Coal is also used to heat buildings and to provide energy for industrial machinery.
Bituminous coal is the most plentiful and important coal used by industry.
It contains more carbon and produces more heat than either lignite or subbituminous coal. It is also the coal best suited for making coke. Anthracite is the least plentiful and hardest coal. It contains more carbon and produces more heat than other coals. However, anthracite is difficult to ignite and burns slowly.