Tidal motion has been used to generate electricity in a power plant on the Rance Estuary in France since the 1960s.
How It Works
One way of capturing the energy in tides to produce electricity is by using a barrage, or “tidal dam”, in an estuary. The dam is closed when the tide is high and, as the water flows out again, it is directed through a turbine in a similar way to a hydroelectric dam.
Another way to generate electricity from tides, is to place turbines, which work just like wind turbines, in the tidal stream. These can be placed anywhere there is fast current, including in rivers, between islands and around headlands.
Tidal dams block estuaries and can disrupt shipping and fish migration if they do not include appropriate provision facilities. Tidal lagoons are less disruptive but still need to be carefully designed and sited.
Underwater turbines, on the other hand, can be completely submerged, deep below the surface so as to have no effect on shipping and very little effect on fish.
Tidal power needs no fuel and produces no pollution.