Wet and wild...Tidal power

An artistic impression of a tidal power barrage. A barrage is a human-made barrier built across a watercourse. Image retrieved from Wikipedia

Tides are the daily rise and fall of ocean water levels caused by the gravitational forces of the sun and moon.

The movement of water at sea and at the mouths of rivers can be used to turn turbines that generate electricity.

Tidal energy generation requires areas with large tides, as more water movement means that more energy is generated. For a tidal energy power plant to efficiently generate electricity, a minimum peak velocity of 1.5 metres per second is required. As tidal energy is only available when the tide is flowing in or out, a plant can only generate electricity for around 10 hours a day.

The depth of the water also needs to be considered when engineers decide which tidal technology to use. The tidal energy power plant must also be able to withstand the local tidal conditions including king tides, the particularly high tides that occur with the full and new moons and rarer events.

Tidal streams and rivers are also being investigated around the world to capture this renewable source of energy. Tidal power plants are already in operation in Europe and the United Kingdom.