A thermal power plant is a complete thermal system that converts thermal energy into mechanical energy to generate a motive force. Sources of thermal energy include the use of coal, petroleum, hot gas, oil shale, biomass, energy, and other fuel combustion, and the release of heat and nuclear energy. Solar geothermal energy, thermal power plants, including steam turbine power plants. Internal combustion engine power units, gas turbine power units and nuclear power units. Thermal power generation is the use of the motive power generated by the thermal power plant to drive the generator's production of electrical energy.