The primary sources of thermal pollution are deforestation, waste heat generated from electric power plants and run-off stemming from hot paved surfaces. The foremost cause of thermal pollution derives from the use of water as a cooling agent in natural gas, nuclear and coal power plants.
Thermal pollution refers to a harmful increase in water temperatures in natural sources, such as rivers, lakes and coastal shorelines. It is the act of altering a natural body of water's temperature. The increase in water temperature is typically caused by either removing vegetation that shades a natural water source or from waste heat generated from certain power plants.
Waste heat is a harmful product of the industrial process. Most electric power plants produce heat from burning coal, natural gas, oil or nuclear fuels. The produced heat converts water into steam, which is used to power the turbines needed to produce electricity. The steam is then cooled and condensed by the introduction of naturally occurring cool water into the hot stream. During this process, the cool water warms anywhere from 9 to 18 Fahrenheit degrees. Afterwards, the water is dumped back into the natural water source from which it came. The cooling process in power generation is paramount to the industrial process. As a result, the extent of thermal pollution is considerable in the majority of developed nations.