Hydro-Electric Power
This is the most common form of generating electricity from water at the moment. Generally what happens is a reservoir is built with a dam in it, a mass of water is held back by the dam, and then suddenly released all at once, sending the water through a turbine at great force.

This kind of system used to be widespread before we started using engines. Hydro-electricity powered things like flour mills and was also used to power machinery. However, these were replaced by engines when fuel to run them was very cheap.

Hydro-electric power is pollution free and safe once it's up and running, although in creating it there can be tremendous disruption and upset to the environment, animals and nearby residents.

We currently get about 2% of our electricity from hydro-electric power, but the chances of increasing that much are pretty unlikely. Finding sites large enough for many more projects of this kind are unlikely.

Tidal Power
This system works by using the gravitational pull of the moon, which creates tidal rises and falls, to produce energy. It's not a very common system at the moment, although experts say the Bristol Channel is one of the best sites in the World for such a system. They believe 5.5% of Britain's electricity could be produced from a tidal power scheme in that area.

Tidal Power generators can be quite expensive to set-up - the costs involved in building such a scheme would be quite high initially, however in the long-term it could enable cheaper electricity.

Environmental concerns are also quite forceful. The disruption to the area and the risk of pollution to the river are a cause for concern, although once up and running, this form of generating electricity is quite safe to the environment.

There is a large-scale tidal power scheme on the River Rance near St Malo in France, which helps produce a considerable amount of electricity. Others in Russia, Canada and China have also been very productive and economical.

Wave Power
The third way of getting power from our waters is by using the energy created by waves. This mass of kinetic energy can be captured quite effectively, and the UK is a good location for such an idea.

Large storm waves which occur in the North Sea would be ideal for producing electricity. Waves which are around 400m long can occur, and experts believe 700 kilowatts of electricity per metre could be captured. It's not just the North Sea either; suitable waters for wave power projects surround our island.

There are several ways of capturing the energy from waves, and some of them, such as building dams or pipes for the water to go up, can be quite expensive, and also could be disruptive to other industry, such as fishing. However, if a suitable site could be found, cheaper and environmentally friendly energy could be created.

Related Links:

- Wind Power
- Water Power
- Energy and Environment Research Unit
- Centre for Alternative Technology
- Renewable Energy