Energy Town

Energy source: hydroelectric

Photo:

Cwm Rheidol, the largest hydroelectric scheme in England and Wales

What is hydroelectric energy?

Moving water contains a lot of energy. Hydroelectric energy involves generating electricity using the power of moving water ('hydro' is a Greek word meaning water).

Modern hydroelectric energy is used in two ways: firstly by building large reservoirs and dams (barriers built across a waterway) to trap water and control its flow; secondly by allowing water to turn machinery as it flows from a high reservoir to a low one.

How a hydroelectric dam works

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  • There are seven 50MW hydroelectric power schemes in the UK.
  • Hydroelectric power plants need to be built near large lakes, reservoirs high above sea level or where a lot of water can be dammed.
  • Hydroelectric energy supplies 1.2% of the UK's electricity.
  • An 110MW hydroelectric energy plant can generate enough electricity for 75,000 homes.