Tidal power plants generate electricity by harnessing the kinetic energy of ocean tides. The basic principle behind tidal power is to use the rise and fall of tides to drive turbines, much like in a hydroelectric power plant. There are a few different methods used to generate electricity in tidal power plants:
Tidal Barrage: This is the most common and well-established method of tidal power generation. A tidal barrage is a dam-like structure built across an estuary or bay with a significant tidal range. The barrage has sluice gates or turbines that can be opened and closed to control the flow of water. During high tide, the gates are closed, trapping the incoming tidal water in the basin. As the tide begins to recede, the gates are opened, and the water flows through the turbines, generating electricity. When the tide turns, and there's low tide, the gates are closed again to trap water and create a height difference between the two sides of the barrage. This height difference allows for continuous electricity generation during both tidal cycles.
Tidal Stream Generators: Instead of using a barrage, tidal stream generators are submerged underwater and placed in areas with strong tidal currents, such as narrow channels or areas between islands. These generators resemble underwater wind turbines and are designed to rotate as the tidal currents pass through them. The rotation of the turbines converts the kinetic energy of the moving water into electricity through a generator.
Dynamic Tidal Power: This is a more innovative and less widely used method. It involves constructing long walls or dykes stretching out into the sea from the coastline. These walls funnel the tidal flow into smaller channels, increasing the velocity of the water. The energy of the faster-moving water is then used to generate electricity through turbines.
Tidal power has the advantage of being a predictable and renewable energy source, as tides are influenced by the gravitational forces of the moon and the sun and follow predictable patterns. However, tidal power plants face challenges related to environmental impacts, high construction costs, and limited suitable locations with significant tidal ranges and currents. Nonetheless, advancements in technology and ongoing research aim to make tidal energy more viable and accessible in the future.