Coal is nonrenewable because it comes from fossil fuels, and fossil fuels take millions of years to form. Fossil fuels are the product of decomposed materials and organisms that have been heated and pressurized for millions of years.
Peat becomes coal when it undergoes chemical and physical changes. Decaying or decomposed plants pile up. In an environment where the peat is covered with water, the process of decay is slower. When the peat is covered with sediment, it only needs heat and time to continue the compaction and process of coalification. This process takes many years because the hydro-carbon compounds in the peat must break down. Another reason why coal is nonrenewable is that it takes a large amount of peat to create a smaller amount of coal. For example, in Kentucky, 1 vertical foot of coal is formed from the compaction of 10 vertical feet of peat.
All fossil fuels are nonrenewable, but some nonrenewable energy sources, such as uranium ore, are not fossil fuels. Producing energy from coal involves mining and burning of the coal in power plants. Although fossil fuels can be inexpensive to extract, burning them negatively affects the environment. Coal, for example, creates waste that is dumped into landfills and abandoned mines. Burning coal releases carbon dioxide, nitrogen oxides and mercury compounds.