A turbine generator is used to produce electrical energy from a spinning turbine. Today, the turbine generator is widely used to transfer the motion of a fluid into electrical energy in stationary power plants. The turbine can be accelerated with many types of moving fluids, either natural or artificial. Natural fluid flow includes rivers and wind, while artificial flow can be generated with heat. Finally, an electrical generator is used to transfer the motion of the turbine into electrical energy.
A turbine must be accelerated by a passing fluid, much like how passing wind pushes on the blades of a windmill. To get reasonable amounts of power from a turbine generator, this fluid must be moving quickly. Wind and water turbines exploit slower, but available, fluid flow. Steam and gas-powered turbines create fluid flow by increasing the temperature and pressure of gases. This heat typically comes from chemical or atomic reactions in a fuel.
Coal is a source of heat used in many countries for electricity production. The fuel is burned in a combustion chamber, producing heat that is transferred to water. The water turns to steam, which then expands under high pressure. The steam is forced to pass through the blades of a turbine. Like a windmill, this fluid flow causes the turbine to start spinning.
Burning coal to create steam is one way to spin a turbine, which is a form of mechanical energy. The source of heat does not have to be coal, however. Nuclear power plants operate in the same basic way, except that nuclear fission of uranium or plutonium replaces burning coal to produce heat.
A hydroelectric power plant uses a flowing river to turn a turbine. This water, of course, is moving because the potential energy of higher ground was converted into the kinetic energy of motion. Similarly, many locations on Earth have much natural wind movement. This is due to regional thermal differences induced by variations in sunlight.
The final step in a turbine generator is to convert the rotational energy of the turbine into electrical energy. This can be accomplished with an electrical generator, a device that uses moving magnets to create an electrical current. For a generator to work, a shaft must connect the spinning turbine to a component called a rotor. Magnets mounted on the rotor move past a collection of metal windings called an armature. This interaction generates the electricity in a turbine generator.