Energy source: hydroelectric
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.
Advantages
- It does not produce any carbon dioxide which can lead to problems like making countries hotter and drier.
- It is renewable - the rain which fills the reservoir never runs out.
- Some dams can store water so we can control when electricity is made.
Disadvantages
- Valuable land is flooded when a reservoir is made: homes and wildlife habitats can be lost.
- A good site for a hydroelectric power plant, such as a mountainous region, is not always near towns.
- There are not many suitable sites in the UK for new hydroelectric schemes.
Locations within the Energy Experience:
