Solid fuel purposes, such as refining metals. Coal is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenic sources of carbon dioxide releases. The extraction of coal, its use in energy production and its byproducts are all associated with environmental and health effects including climate change. Variations such as smokeless coal can be formed naturally in the form of anthracite, a metamorphosed type of coal with a very high carbon content that gives off a smokeless flame when set alight. Coke is a fuel with few impurities and a high carbon
Coal oil Coal oil Coal oil is a shale oil obtained from the destructive distillation of cannel coal, mineral wax, or bituminous shale, once used widely for illumination. Chemically similar to the more refined, petroleum-derived kerosene, it consists mainly of several hydrocarbons of the alkane series, with 10 to 16 carbon atoms in each molecule and a higher boiling point (175–325 °C) than gasoline or the petroleum ethers and lower than the oils. Because kerosene was first derived from cannel coal, classified as terrestrial type of oil shale, it continued to be popularly referred to as "coal oil" even after production shifted