Hydropower provides less than 2% of the UK's power*
What is it?
Hydropower is energy generated from the movement of water through rivers, lakes and dams.
Once built, the power stations do not release the greenhouse gas carbon dioxide. Hydropower is not vulnerable to changes in price like oil or gas.
Power stations which rely on rainfall can be vulnerable to drought. Those which pump water back uphill (pump storage) rely on off-peak electricity. Large dams and reservoirs have a big impact on their immediate environment and the people who live near them.
In the UK we have already built dams on many of the rivers best suited for generating hydro-electricity. That means large, new developments are unlikely but the use of small-scale systems may increase.
* Based on Department of Energy and Climate Change figures 2010. The exact proportions change yearly.