A steam turbine power generating plant is the most common type of power plant today. This type of plant converts heat into electricity usually using a boiler, and a turbine to drive an electric generator. Large-scale commercial size systems use steam produced from a variety of sources including nuclear reactions, burning fossil fuels and wastes, and even geothermal energy. The most common fuels used at steam turbine plants to produce steam are coal, oil, and natural gas.
The steam boiler is essentially a large tea kettle and the steam turbine acts much like a windmill to turn the generator to make electricity.
After the steam passes through the turbine, it is condensed back into water and pumped back into the boiler to be reheated into steam again. This condenser usually uses cool water from a lake, river, or bay or may use a large cooling tower.