Tidal energy is also known as tidal power, it is a form of hydropower that converts the energy collected from ocean tides into useful types of power, most specifically electricity. Tidal energy has been around for many years but the use of it today is minimal at best. Being that tidal energy relies solely on the oceans’ tides, which are always there and always will be, it has the potential to be a front-runner in the coming future of electricity. Though it is not yet a top source of renewable energy it is much more reliable than others; like wind and solar. Still, there is some debate over whether or not it is worth pursuing based on both the advantages and disadvantages of this alternative energy source.
Hydropower is one of the oldest sources of energy; it has been around since the 11th century, at least. England was one of the first to put to good use the power of water. (The Energy Story) They used water wheels or watermills to generate mechanical power to mill grain, produce flour for bread, malt for beer, etc. (World Colleges Information) Like watermills, small tidal mills were used along portions of rivers to grind corn. (Renewable Energy) Though it is one of the oldest forms of energy, it is also one of the least known and used. (Water Wheel) Still, there are ways of harnessing it and while it has not evolved much since the Middle Ages there have been and continue to be advancements. It is only recently that the idea of exploiting the full power of the tides in estuaries has taken off.
Tides can be defined as the rise and fall of the ocean water in coastal areas, usually occurring twice in a 24-hour period. Though it is mostly due to the gravitational pull of the Moon on the Earth, the Sun also contributes to this phenomenon. It is the interacting movements of the Earth, Moon and Sun with which these tides originate from. During a full or new moon all three factors are positioned in a straight line and thus create much larger spring tides. (World Colleges Information) In order to generate enough power from these twice daily tides, a magnitude of at least five meters from high tide to low tide needs to be reached. There are only about 40 sites around the world where tides are able to meet this standard. Obviously the higher the tides, the greater the distance is from high to low. The amount of electricity that can be drawn from tides is highly dependent on this as well as inversely proportional to the cost of the produced electricity. As a result these sites that meet the standards are considered to be much more economical. However, with all of the limitations that come with the tidal power industry only about two percent of what is available has the potential to be exploited for electricity generation. (World Colleges Information) The process used to harness this energy and ultimately power is relatively simple. Tides produce both kinetic and potential energies; kinetic by the ebb and surge of the tides and potential from the differences in high and low tides. The two forms of energy work hand in hand in the generation of electricity. Tidal energy can be harnessed in three different ways at this point. (Tidal Energy, Odec) There are other alternatives that have been proposed throughout the years, many of which have not been followed up on or have been reassessed a year or two later but nothing further. There are tidal fences, which are used to block bodies of water between two separate landmasses forcing the water to go through it and turn its turbines thus generating electricity. These fences have vertical axis turbines mounted to them and are cheaper to install than tidal barrages, but have a larger influence on the environment as well as marine animals. (Hydropower) Like wind turbines there are tidal turbines. These tend to be heavier and more expensive because they need to be much sturdier, being that water is a lot denser than air. (Hydropower) Despite them being a little more expensive...
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