Tidal Energy | Universe Today

Written by Tega Jessa

Tidal energy is a type of renewable energy that produced by the movement of ocean tides. The tides are the movement of water influenced by the gravity of the moon and to a lesser extent the sun. Tidal energy is a great source of renewable energy because it harnesses a vast resource to produce reliable energy on the same order as a hydroelectric dam.

There two types of tidal energy turbines and each make use of the ocean tides in different ways. First there is the barrage. This is a modern generator based on ancient tide mills. The concept of their function is quite simple. A dam is built with two gates. When the tide comes in the water flows into the dam and when the tides starts to ebb, the gate that was opened to let the water rush in automatically closes. The stored water is then released into a channel directed towards the turbine. The force of gravity causes the water to flow towards the turbine and the kinetic energy is eventually converted into electricity. However, the barrage has recently raised some concerns about the impact it might have on coastal and marine environments. Tidal barrages are normally built across tidal estuaries and studies have shone their simple presence can dramatically change the chemical balance of the water and alter the habitats of coast animals and plants.

The second type of tidal energy generator is a tidal stream turbine. This is more like an underwater wind mill. The turbine is powered by the movement of the water. It is considered to have many advantages over the barrage, such as a much smaller impact on the surrounding environment.

Both of these types of Tidal generators use turbines and like wind mills they can come in different designs. One is the vertical turbine. The propellers are parallel to the shaft of the turbine. The other kind is a horizontal shaft which is constructed more like traditional wind mills.

Tidal energy generators produce a lot of energy and they have a big advantage over wind turbine because of the greater density of water. They also are more reliable because of the unchanging cycle of the tides. This means a steady amount of power is available over longer periods of time. However the current technology still does not harness the full power of the ocean. The estimated potential energy that can produced is on the order of 64,000 MWe.

At the moment only a few places in Europe, Asia, and Canada use tidal energy but like other renewable sources of energy the technology is steadily improving.

If you enjoyed this article there are others on Universe Today that you will be sure to enjoy. There is a great article about how wind turbines works. There is also an article about how solar power works.

There are also great resources online. The ocean energy council has a website with a lot of great information about tidal energy. There is also a great article on on the U.S. Department of Energy's website.

You can also check out Astronomy Cast. Episode 144 Space Elevators is quite interesting.

Filed under: Astronomy