A propeller is attached to an electric generator and with the rotation of the propeller electrical energy is generated

This is reckoned to be one of the most user friendly methods of producing electricity

Large number are needed to created electricity known as wind farms

A photovoltaic cell will generate a voltage when rays of light from the sun strike it

Used generally in calculators, satellites and roof tops

Environmentally friendly and no toxic waste is generated

Experimentation with this form of energy is still at an early stage although some larger scale projects are in place, the Thames estuary is one example

Movement of the waves cause paddles to move up and down and this movement is converted to rotary movement that rotates the turbine blades of the electric generator

Wave energy is not yet used commercially to date but has potential, especially for island countries

It is environmentally friendly and no toxic waste is generated

Biomass energy comes from a number of biological sources

There are different sources of this type of energy including agricultural production of methane gas through to the growth and processing of willow which can then be burnt to produce steam in an electrical generating station

Willow can also be shredded and pressed into wood pellets suitable for home fuel

Hydro power is an alternative way of producing electricity from the power produced by water under pressure

A typical setup requires the construction of a dam

Behind the dam water is allowed to build up forming a lake. The deeper and larger the lake, the greater potential of producing large amounts of electricity

Geothermal energy comes from the heat in the earth beneath the planet's surface

One way of producing electricity from geothermal energy is by drilling deep wells into geothermal reservoirs

The hot water that rises emerges at the surface as steam. The steam is used to produce electricity. If the water is not hot enough to produce steam, it can still be used to heat homes