GENERATORSOF

ELECTRICITY

COMMON TYPES OF GENERATORS• 1) STEAM TURBINE GENERATORS

a) Powered by fossil fuelsb) Powered by nuclear energy

• 2) COMBUSTION TURBINE GENERATOR• 3) HYDROELECTRIC GENERATOR• 4) WIND TURBINE GENERATOR

Steam turbine Generator• Almost 88% of all Electrical generation in US is with steam. They tend to be the most efficient.•Fossil fuel (mostly coal, also oil and natural gas) is burned to create high pressure, high temperature steam which turns a turbine. This spins a shaft which drives the generator creating electricity.

Steam turbines from nuclear fuel

Ever wonder how a nuclear reactor works? Here are some graphics that will quickly bring you up to speed on how electric generation works using nuclear fuel.

•Enriched radioactive uranium is used to heat water which turns to steam. The steam turns the turbine which is connected to a generator that produces electricity.•This form of fuel requires uranium atoms to be split (nuclear fission). It releases much more heat than burning fossil fuels, thus in many ways is more efficient.•It creates a continuous reaction, creating energy that needs to be monitored and kept in a special structure to keep radioactivity contained.•No GHG emissions occur, but what to do with the nuclear waste is an issue..

Combustion turbine (gas) generator•This type of generator uses low grade petroleum products or natural gas to heat air. •The heat from the burning fuel causes the air to expand. This sudden expansion of air, causes the heated air to rush toward a turbine which rotates to generate electricity.•These are often used as supplemental sources of electricity which are fired up during peak electricity usage times. They are less efficient than other generators.

Hydroelectric Power plant•Flowing water is used to turn a turbine to create electricity.•A dam is built on a river; a large amount of water is funneled into a small tube (Penstock). The force of the water turns the turbine which generates electricity.•Building the dam is expensive, can harm wildlife in and around the river/dam area , but no GHG emissions occur.

falling from water.

How It Works

Hydroelectric

Wind Turbine•These turbines use wind to turn a turbine which generates electricity.•As the rotor blades face into the wind, they turn a shaft which in turn causes the parts of the generator to move and produce electricity.•No GHG emissions occur. Many are bothered by the sight of them in their back yard or ocean view. There is concern they could harm migrating birds and bats.

FROM WHERE DOES MOST OF OUR ELECTRICITY COME?

• Burning of Coal to power steam turbine generators:42%

• Burning of Natural gas to power steam and combustion turbine generators:25%

• Nuclear energy (Uranium -235):19%

• Energy from Hydroelectric power:8%

• Energy from Wind:3%

• Other:3%