Tidal Power

Tidal power is a means of electricity generation achieved by capturing the energy contained in moving water mass due to tides

The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy - around 20% of Britain's needs.

Tidal power can use either conventional or new technology to extract energy from a tidal stream.

The conventional technology required to convert tidal energy into electricity is very similar to that used in traditional hydroelectric power plants. Typically a barrage with turbines is built across an estuary or a bay.

As the tide ebbs and rises, it creates a height differential between the inner and outer walls of the barrage. Water can then flow through the turbines and drive generators. Some tidal barrages operate on both the rising and falling tide, but others, are designed to operate purely on the falling tide

Undersea tidal power turbines are an emerging technology which could become an important source of renewable energy for Britain. Although they tend to follow the same lines as wind turbines, due to the greater energy density available in ocean currents, these devices can be much smaller than wind turbines.

Although like other renewable sources the output is not continuous, it is at least predictable and the times of generation and the output available can be accurately forecast.

The UK is favoured with many potentially good sites, to be found mainly along the west coasts of England and Wales. The total output from these sites could amount to 50 TWh/year.

The Mersey can offer more tidal power potential than any other river in Europe, by virtue of its 10-metre tidal range and strong currents. According to initial estimates, it could generate up to 2,000 megawatts of electricity, enough to power 15 per cent of the North-west's electricity requirements.

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