Tidal Energy

Tidal means structure changing in a planet, caused by the gravitational interaction with another planet.The gravitational pull of the moon and the sun cause the changing of the sea-level  twice a day on the Earth.The period from the smallest water-level, to the highest sea-level called upstream tides, while the period between the highest and the smallest sea-level is called downstream tides.The sea-level changing between the rising and the falling of  tides is called tidal range. These work rather like a hydro electric scheme, except that the dam is much bigger.

A huge dam is built across a river shore. When the tide goes in and out, the water flows through tunnels in the dam.The ebb and flow of the tides can be used to turn a turbine, or it can be used to push air through a pipe, which then turns a turbine.Large lock gates, like the ones used on canals, allow ships to pass.If one was built across the Severn Estuary, the tides at Weston-super-Mare would not go out nearly as far,there would be water to play in for most of the time.But the Severn Estuary carries sewage and other wastes from many places out to sea. A tidal barrage would mean that this stuff would hang around Weston-super-Mare an awful lot longer! Also, if you're a wading bird that feeds on the exposed mud flats when the tide goes out, then you have a problem, because the tide won't be going out properly any more.Finally the electricity gets produced by the rotation of turbine.