Energy from Water (Cambridge (CIE) IGCSE Combined Science): Revision Note

Wave & tide power

• Energy can be obtained from the kinetic store of the waves and tides

• The motion of the water is used to turn a turbine, which turns a generator, which generates electricity

Wave power

• Wave power uses underwater turbines 

• The waves move the water which causes the turbines to turn

Turbines using wave power

Underwater turbines generate electricity

Tidal power

• Tidal power uses tidal barrages to store water at a height as the tide comes in and goes out

• When the barrage is opened, water flows through a channel over a turbine

Tidal barrage

A tidal barrage stores water at a height and then opens a gate allowing water to flow over a turbine

Hydroelectric dams

• When water is stored above ground level, it has energy in its gravitational potential store

• This energy can be transferred to kinetic energy if the water is allowed to flow down the slope

• Flowing water turns the turbine to generate electricity

A hydroelectric dam

A hydroelectric dam transfers energy mechanically from the gravitational potential energy store of the water to its kinetic energy store. The moving water turns the turbine