Why do thermal power plants need to reject heat? How much heat is rejected in a typical thermal power plant?
Over 80% of the worlds electricity is produced in thermal power plants; the major exception is hydraulic power plants. Thermal power plants include: coal, gas-fired, and nuclear. Thermal power plants convert a portion of the heat received from their fuel into work. In accordance with the Carnot principle, the portion not converted into work ends up as waste heat. A thermal power plant with an electrical output of 1000 MW(e) and an efficiency of 35% requires a heat input of 2860 MW(t). The part of the heat input that is not converted to work 1860 MW(t) is rejected as low temperature waste heat to the environment.
