Tide of water rotating a turbine
Tidal power has great potential in future for electricity generation because of the massive size of the oceans.
Tidal energy is the utilization of the Sun's and the Moon's gravitational pull on the water here on Earth. Our seas and oceans contain a great amount of energy as they come crashing to our shorelines. Tidal energy comes from harnessing this energy into a useful type of energy, generally as electrical energy.
Tidal energy traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin; the sluice is then closed, and the only way the water could escape as the tide fell was by passing through and propelling a waterwheel, so providing turning power.
As the tide comes in, it is allowed to build up against the dam until there is a difference of 5 feet between one side and the other. Then it is allowed to pass through the turbines, driving them and generating electricity. When the tide begins to fall, the turbine blades are reversed, and the water generates electricity again.
The amount of electricity generated depends on the ‘head’ of water – the difference in the level of the water between one side of the dam and the other. The larger the head, the greater the amount of electricity that will be generated, because the water is under great pressure and so turns the turbines with more force.
The next five years are critical for tidal energy devices to prove both technical and economic viability of the technology.