Wave, tide and falling water energy resource

Sea waves moving up and down can be used to drive turbines directly to generate electricity.

of the waves \(\rightarrow\) electrical energy.

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

Like tidal barrages, hydroelectric power (HEP) stations use the 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 energy.

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.
The rotting vegetation underwater releases methane, which is a .

��ý