Coal-fired and nuclear power plants are thermal power plants. A feature of such power plants is the conversion of the internal energy, chemical or nuclear, contained in the fuel into heat, then into mechanical and finally electrical energy.

(Source: https://www.statista.com/statistics/269811/world-electricity-production-by-energy-source/ (07.11.2023))
prof. Janusz Wojtkowiak, Faculty of Environmental and Energy Engineering, Poznan University of Technology