TIDAL POWER: How it Works

 A large amount of energy is stored in the tides. The tides go in and out, and we can capture energy from this with tidal power stations. Tidal power stations can stretch over a delta, estuaries, beaches or other places that are affected by the tides. A barrage is first set across a beach or river. When high tide comes in, water flows through a turbine to create electricity. Now some of the water is up behind the barrage. A gate is lowered from the barrage, capturing the water above it. When low tide comes, the gate is raised and the water flows out, first transferring its energy through turbines. This way, electricity is created with a two-way turbine. Some tidal power stations can produce 320 megawatts of electricity.

TIDAL POWER: History and Sites

 Tidal mills were invented in the early 1900's. They didn't have two-way turbines then, so they could only use one tidal direction. They chose to capture the tides as they were receding, because there was the most possible outcome from there. When the tide came in, the floodgate lowered, trapping the water above it. When low tide came, the gate was lifted up, and the water turned a water wheel.

 Tidal power stations are already being used in Canada, France, Russia and China. The station that generates the most electricity is on the Rance River, in France. It generates 320 megawatts of electricity. A possible site for a tidal power station is at the Bay of Fundy, between New Brunswick and Nova Scotia. The tidal head difference there is 50 feet.

TIDAL POWER: Design Issues and Problems

 Tidal power stations are very expensive to build and they often create electricity when it isn't needed as much. The tides are always changing, but the need for electricity much smaller at night then in the day.

 Tidal power stations also have environmental problems. Many fish like salmon swim up these estuaries where the barrages are and have already been killed by the turbines. The barrage also destroys homes to many birds, fish and other animals.