A fossil fuel power plant burns fossil fuels such as coal, natural gas or petroleum (oil) to produce electricity.

Fossil fuel power plants are designed on a large scale for continuous operation. In many countries, such plants provide most of the electrical energy used.

A fossil fuel power plant always has some kind of rotating machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or in small isolated plants, a reciprocating internal combustion engine.

Byproducts of power plant operation must be considered in the design and operation. Waste heat due to the finite efficiency of the power cycle must be released to the atmosphere, often using a cooling tower, or river or lake water as a cooling medium. The flue gas from combustion of the fossil fuels is discharged to the air; this contains carbon dioxide and water vapor, as well as other substances such as nitrogen, nitrous oxides, sulfur oxides, and (in the case of coal-fired plants) fly ash and mercury. Solid waste ash from coal-fired boilers must also be removed, although some coal ash can be recycled for building materials.