Tidal Energy
Another type of ocean energy is tidal energy since when tides comes into the shore, they can be trapped in reservoirs behind dams. Tidal power is actually a form of hydropower that exploits the movement of water caused by tidal currents or the rise and fall in sea levels.
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Tidal energy is produced thanks to the use of tidal energy generators which are large underwater turbines placed in areas with high tidal movements, and designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity.Tidal power has enormous potential for future electricity generation because of the massive size of the oceans. |
The potential of tidal power has been recognized for very long time (small dams were built along oceans since 11th century). However, compared to river dams, tidal-power projects are much more expensive, since massive structures must be built in a difficult saltwater environment. Cost effectiveness is actually a main reason why tidal power hasn't yet found its place among top used renewable energy sources despite its huge potential. Tidal power in order to function at sufficient level needs very large increases in tides, of at least 16 feet between low tide to high tide and this is the main reason why there aren't many areas on Earth that meet these demands. However one of these areas is definitely La Rance Station in France, the largest tidal power station in the world (also the only one in Europe) is in the Rance estuary in northern France that provides enough energy to satisfy demands of 240,000 homes in France. Capacity of this tidal power plant is approximately one fifth of a regular nuclear or coal-powered plant. Main problem of all tidal power plants is the fact that they can only generate when the tide is flowing in our out, which counts for only 10 hours per day. However there is also advantage that tides are totally predictable, so we can plan to have other power stations generating at those times when the tidal station is out of action, which is something that can't be done with certain other renewable energy resources (wind energy).
Tidal energy has many advantages (it is renewable energy source since tides will continue to ebb and flow and it produces no greenhouse gases or any waste, it needs no fuel in order to work, since tides are totally predictable it can produce electricity reliably and once built it's not expensive to maintain), but there are also some negative sides as well. Cost effectiveness is still very serious issue since building one of these power plants requires a very vide area and this also brings some environmental problems since it completely changes environment in this area and affects life of many ecosystems, especially for birds that rely on the tide uncovering the mud flats so that they can found food. There is also the already mentioned fact of limited working time of only about 10 hours, when tide is actually moving.
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