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• Potable water
• Renewable energy
• Solar collectors
• Solar power
• Tidal energy
• Wave energy
• Wind energy

arable power station UK	PS10 solar power tower in Spain

Renewable energy

Renewable energy is defined as energy which is generated from available natural resources which are not depleted when when this energy is taken from it.

Examples of these energy types include solar energy, wind, rain, tides, hydroelectricity and energy from geothermal sources.

The following table shows the amount of pollutants not released into the atmosphere when using a renewable energy source but which would have been released into the atmosphere from a fossil fuel power station.

Emission savings from using renewable energy to generate 3831MW of electricity

emission	tonnes per annum	tonnes per MW	tonnes per 2TW
CO2	4,329,408	1130	2,260,000,000
SO2	100,684	27	54,000,000
NOX	30,205	8	16,000,000

The tonnes per annum is the amount of emissions saved by the use of windpower in generating 3831MW of electricity instead of using fossil fuels
(source: wind energy database - UKWED)

Wind farm Scotland, UK	Meyersdale Wind Project southern Pennsylvania

Energy generated from these renewable sources contributes nearly 20% of our planet's annual energy consumption. Over half of this comes from the biomass and the burning of organic materials for heat, light and energy.

Biofuels are derived from biomass material. The term 'biofuels' includes agrofuels which are produced from crops specifically grown to be used as fuels. Plants with a high sugar content or plants containing vegetable oils are grown to produce these fuels.

Wind power is a significant source of renewable energy. Wind turbines can extract energy from the wind and generate electricity. In the UK wind energy is an important part of the government's plans to produce electricity from renewable sources. Wind farms are being built on land and offshore. The UK is well positioned to take advantage of wind power.

Hydropower refers to the potential energy in water and this energy can be used to generate electricity.

Solar power is simply the energy of our Sun. Focusing that energy to create steam to drive turbines generates electricity. Examples are the 354 MW SEGS power plant in the Mojave Desert and the PS10 solar power tower in Spain.

Wave power refers to the energy in waves. The wind creates the waves on the ocean surface and this energy can be used to operate a range of devices to generate electricity.

Tidal power refers to the energy in the twice daily tides. The tides are the result of the gravitational pull of the moon and, to some extent, the Sun.

Geothermal power uses heat sources within the Earth. These heat sources are used to boil water and the resulting steam is used to generate electricity. The hot water can also be used for central heating for local communities.