Generating Electricity: Steam Turbines

A conventional steam electric power plant converts fossil fuels - coal, gas or oil - into electric energy. Steam plants generate most of the electricity in the United States. Fuel burned in the boiler releases heat, which boils water and converts it into high-pressure superheated steam. The steam enters a turbine where it expands and pushes against blades to turn the generator shaft to create electric current. After the steam passes through the turbine, condensers convert it to water that is returned by pumps to the boiler to repeat the cycle. Combustion gases exit through the stack. This process is basically the same for all fossil fuels. A stream of hot air carries coal, crushed to powder for easy burning, into the boiler. Oil generally enters as a fine spray of droplets in hot air.