Explanation: Tidal energy is the conversion of oceanic tides into useable electric energy. Related questions Why do hydroelectric dams raise the water behind them high as possible? What is the name of the dam in Paraguay that is home to the world's largest hydroelectric plant?
Why do hydroelectric dams have limited lifetimes? How do hydroelectric dams affect river systems? The main environmental concerns with tidal energy are from the turbine blades striking or entangling marine organisms, as higher speed flowing water increases the risk of organisms being pulled near or through these devices.
As with all offshore renewable energies, there is also a concern about how the creation of electromagnetic fields and acoustic outputs may affect marine organisms. Tidal stream generators draw energy from water currents in much the same way as wind turbines draw energy from air currents. However, the potential for power generation by an individual tidal turbine can be greater than that of a similarly rated wind energy turbine, due to the higher density of water relative to air water is about times the density of air , which means that a single tidal generator can provide significantly more power at low tidal flow velocities compared with a similarly sized wind turbine.
While the initial cost of building tidal energy plants is high, tidal energy power plants are expected to run for a very long time, which make them more cost-effective in the long run. Solar panels are fragile, less efficient, and can require costly maintenance.
Wind turbines operate at much higher speeds, which can wear out moving parts more quickly. Geothermal energy can be very costly to install and require deep wells or large open areas. Depending on geographical location, the cost of tidal energy is about cents per kWHr of electricity produced compared to about cents per kWHr of electricity produced for solar and about 2.
Future advancements in technology and manufacturing efficiency will help to drive the cost down for these renewable energy sources, making them even more cost competitive with traditional energy sources that come from fossil fuels. Currently, 19 countries worldwide are investing in tidal power systems.
As with wind power, tidal turbines have specific site requirements. Tidal stream turbines may be arrayed in high-velocity areas where natural tidal current flows are concentrated, such as the west and east coasts of Canada, the Strait of Gibraltar, the Bosporus, and numerous sites in Southeast Asia and Australia.
Such flows occur almost anywhere where there are entrances to bays and rivers, or between land masses where water currents are concentrated. Animals could swim around the structure, and smaller organisms could swim inside it. Large predator s like sharks would not be able to penetrate the lagoon, so smaller fish would probably thrive. Birds would likely flock to the area. But the energy output from generators using tidal lagoons is likely to be low. There are no functioning examples yet.
China is constructing a tidal lagoon power plant at the Yalu River, near its border with North Korea. A private company is also planning a small tidal lagoon power plant in Swansea Bay, Wales. Using DTP, enormous dams as long as 50 kilometers 31 miles would extend straight from the shore into the open ocean. Often used as a source of hydroelectric power.
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A tidal bore occurs along a coast where a river empties into an ocean or sea. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Nevertheless, tidal energy is usually highly predictable in both the amount and the timing. Tidal energy is the most promising source of ocean energy for today and the near future.
Tidal energy plants capture the energy in the changing tides.
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