Steam turbines are used to transfer energy to drive a machine. They are used to create electricity from various energy sources that produce the raw material steam. These energy sources include fossil fuel, nuclear energy, geothermal energy and even solar power. Steam turbines have also been used to power locomotives and ships. Steam turbines convert heat energy into kinetic energy and from there can create electric energy via a generator.
The steam turbine system is used to create over 80 percent of the world's electricity supply. In order for the turbines to work, steam must first be created from an energy source. These include fossil fuels, solar energy, geothermal energy and nuclear energy. Recently, agricultural waste and renewable materials have also been used as raw material in the combustion step.
Fossil fuels are burnt in order to release the energy in the chemical bonds. For example, gas, oil and coal combustion is used to heat water (or an alternative substance such as freons) in a steam boiler. The steam produced from the boiler runs through a controller steam valve and through the turbines.
Each side of the turbine has a different pressure due to the hot expanded steam on one side and colder denser air on the other, and so the steam runs through the turbine to the colder side, turning the turbine rotor. Rotors can be "impulse," which means the force of the steam entering turns the rotor, or "reaction," where the rotor is turned by the steam as it leaves the blades. Once the steam has been through the rotors and drained of energy, it can be recycled via a steam condenser back into the steam boiler to be boiled again and reused.
As the steam heat energy has now been turned into kinetic (movement) energy, the rotor can be used to power an electric generator, producing the final product, electricity.
Steam turbines were also used to create motion in locomotives. The kinetic energy of the turbines was converted into turning force to drive the locomotive wheels. This use of steam turbines was not very successful and was abandoned in the United States in the 1950s.
Steam ships use the same principle as locomotion production to power a ship. The raw materials for the steam are burnt and the heat produced is used to create steam from a water boiler. The steam turns the turbine and the kinetic energy is used to turn the propellers of the ship and move the ship through the water.
- steam image by yaros from Fotolia.com