Tidal Energy (Tidal Power) Facts for Kids

by Andy Goldman on November 11, 2012

Tidal Energy is the energy produced from the tidal power, which is nothing else than the power of a tide. Tidal Power is more predictable than the other two major renewable energy sources, solar power and wind power.

Facts about Tides, the sources of Tidal Energy

Tides are simply the rise and fall of water level and are caused by combination of two forces:  the gravitational force of either the sun or the moon and by the rotation of the Earth.

There are places which experience two not just one high tides and an equal number of low tides. The rise and fall of water levels varies from place to place but it is measured and it is known at the specific place and it is known at the tidal range. A tidal range of 10 feet (3 meters) is enough to enable us to produce tidal energy which will be economically viable.

Is Tidal Power Renewable?

Yes Tidal power is renewable because tides will continue to happen as long as the sun and the moon exist and as long as the Earth turns! Water is not used at all in this process; it just rises and falls so tides will continue to ebb and flow.

There are basically 3 ways to capture the power of the tide and convert it into useful tidal energy. These are the: Tidal Barrages, Tidal Fences and Tidal Turbines.

Tidal Barrages

A barrage is a dam which is built along a watercourse so as to increase the depth of the water. Barrages are built on inlets on the seashore. A barrage has gates which allow the water to come in at the instance of a high tide. The water is trapped in the barrage and when the water level on the outside of the barrage lowers the power of the outgoing tide is used to turn the generator and produce electricity. The outgoing tide is also known as ebb. Modern generation systems used at barrages produce electricity both directions, that is, in the inflow and outflow of water.

Tidal Fences

Tidal Fences are another way to capture the power of the tide and convert it into useful energy. In this case vertical axis turbines are mounted in the fences which are used to fence the water. The water is forced to pass through the turbine and thus turn the turbine the power of which produces electricity. While tidal barrages are built at inlets, tidal fences are built in areas where there are channels of water.

Tidal Turbines

Tidal turbines operate with the same philosophy as the wind turbines and they are basically water turbines which are located under the water at locations where there is strong tidal flow. This way when the water flows, it turns the turbine which produces electricity.

As with any time of power, Tidal power has both advantages and disadvantages.

Tidal Power Advantages

Some of the advantages of Tidal power are:

  • It is cheap to produce
  • Tides are predictable thus tidal power is predictable too
  • Being predictable it makes it very reliable and thus we can plan its used
  • It does not produce any waste or pollution

Tidal Power Disadvantages

As with every form of energy, Tidal Energy has some disadvantages:

  • Not many sites in the world are suitable for Tidal Energy.
  • There is high initial cost, especially in the case of Barrages
  • It only produces energy for about 10 hours, the period that the tide lasts
  • It may cause disruption of the animal and plant life in the area where the plants are built

Tidal Plant Installations

Tidal Energy has been used for many years now. It is one of the oldest sources of renewable green energy. It is known to have been used by mills, known as Tide mills, along the coasts of Spain, France and England since 787 AD. Tide mills used to store the water of the tide in a pond and then empty the water through a wheel that would give power to the mill.

There are currently several commercial tidal plant installations in certain parts of the world:

  • La Rance, France
  • Annapolis Royal in Nova Scotia, Canada
  • Kislaya Guba, Russia
  • Saint Bernandino Straits, Philippines

Some more Tidal Energy Facts

In addition to all the Tidal Energy facts given you may find some more facts below:

  • Although there is a high initial cost in setting up a tidal energy plant, its operational cost is very low because there is no need for staffing it. The tides do their work unattended
  • It is hard to give the cost of electricity produced per kW from the tidal power because the cost varies per geographical area.
  • Tidal Turbines are gaining popularity among the methods of tidal energy due to their lower cost than the other two methods
  • Tidal Energy plants have efficiency of 80% which is probably the highest of the other renewable green energy sources and especially some forms of solar energy
  • Tidal Energy plants can be built in such a way that they would be beneficial to the community in more forms than one, like acting as a bridge between to areas of land.
  • The USA has no tidal plants as of today.

Tidal Energy is one of the 5 renewable green energy sources and despite of the fact that is location specific, it has great potential at places with high tides.

About the Author

Andy Goldman


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