All About Tidal Energy
Did you know that 71% of the Earth's surface is covered with water? Most of it is, of course, in oceans and seas. Because this water doesn't flow like the water in the rivers, the dams that we use to obtain hydroelectric energy are useless in here. In this case, tidal energy is used to obtain electricity.
The action of the sun on the surface of the oceans, and the gravitational pull of the Moon, cause the creation of the tides. When these celestial bodies are in motion, they act on the surface of the ocean, by raising and lowering it periodically. This is how tides appear. But not all the tides can be used to obtain energy. The location and the time of extraction of energy are very important. The best locations are in the areas where the tides are larger and more suitable for this process. One of the best locations in the world is in U.K. Because of the unusual high tidal range found on England's coasts, many tidal plant constructions were built in here. These sites are built in estuaries, and concentrate the power of the large tides and transform it into electricity. It takes a tidal range of 7 to 10 m for an economical operation. This way, the turbines are secured with enough water, and the volume of energy is higher.
These tidal energy power plants are actually a series of gated sluices and turbine generators. In here, the force of the tides is converted into electricity. Tidal power has been used for centuries in England and France, mainly for the milling of grains. Actually, the first tidal plant in the world, was built in France, 45 years ago, and generated about 240MW of power. It was a huge amount at that time.
One of the advantages of this form of renewable energy is that it doesn't pollute. It has no contribution to the acid rains or the global warming. For these reasons, tidal energy is considered environmentally friendly. Another advantage is that, the tidal plants can use both of the variations in the sea level. This way, the tidal energy plants work 24/7 and no energy is wasted.
New technologies of extracting tidal energy are developed. Researches are working on technologies able to extract the energy directly from the streams. This will reduce the costs of the extraction, and will provide us with more tidal energy.