HYDROPOWER means making electricity out of the movement of water.

In large hydroelectric power stations, a dam is created to store the water and allow it to fall.

But others, like the proposed station on the Longbridge Weir, use the natural flow of rivers and weirs as the water falls.

The more water and the further it falls, the more energy it creates.

The water turns a turbine and the energy created from that turbine moving is transformed into electrical power by a generator.

Hydropower has been used for hundreds of years.

Prior to the widespread availability of commercial electric power, it was used for irrigation, and operation of various machines, such as water mills, textile machines, and sawmills.

Hydroelectric power now supplies about 19% of world electricity, compared to 16 % in 2003.

Hydropower produces essentially no carbon dioxide or other harmful emissions, in contrast to burning fossil fuels, and is not a significant contributor to global warming through CO2.