The huge weight of water trapped behind a dam is a source of potential energy that a hydroelectric power station transforms into electricity.
Hydro power stations can turn on very quickly. Some hydro power stations can go from zero to full capacity in less than 60 seconds!
This fast, reliable and flexible source of electricity is particularly useful when there are major changes in the nation’s electricity demand, such as when millions of kettles are switched on during television breaks.
The video animation below outlines the processes of how a hydroelectric dam works.