Wave, tide and falling water energy resource
Wave
Sea waves moving up and down can be used to drive turbineRevolving machine with blades that are turned by wind, water or steam. Turbines in a power station turn the generators. directly to generate electricity.
kinetic energyEnergy which an object possesses by being in motion. of the waves \(\rightarrow\) electrical energy.
Tides
Huge amounts of water move in and out of river mouths each day because of the tides.
The moving water has kinetic energy
A tidal barrage is a barrier built over a river mouth to make use of the kinetic energy in the moving water.
The barrage contains electricity generators, which are driven by the water rushing through tubes in the barrage.
Kinetic energy of the moving water \(\rightarrow\) electrical energy
Hydroelectric power
Like tidal barrages, hydroelectric power (HEP) stations use the kinetic energyEnergy which an object possesses by being in motion. in moving water.
Often, the water comes from behind a dam built across a river valley.
The water high up behind the dam contains gravitational potential energyThe energy an object possesses due to its position above the ground..
This is transferred to kinetic energy as the water rushes down through tubes inside the dam.
The moving water drives electrical generators, which may be built inside the dam.
Gravitational potential energy of the water \(\rightarrow\) kinetic energy.
Kinetic energy of the falling water \(\rightarrow\) electrical energy
Advantages
- Waves, tides and hydroelectric power are renewable energy resources and there are no fuel costs.
- No harmful polluting gases are produced.
- Tidal barrages and hydroelectric power stations are very reliable and can be easily switched on.
Disadvantages
- It has been difficult to make wave machines big enough to produce large amounts of electricity.
- Tidal barrages destroy the places where birds and fish live.
- Hydroelectricity dams flood farmland and push people from their homes.