How to Use Wave or Tidal Energy to Produce Electricity

Tidal energy is a clean and reliable source of electricity.

Mankind started using tidal energy in the eighth century C.E. in the form of tidal mills. The incoming tide was used to fill a storage pond, which was then emptied when the tide dropped. The tides turned waterwheels, which transformed the rotational energy of the wheels to mill grain. Tides are caused by the gravitational pull of the moon and the rotation of the Earth. Today, the same principle is used to generate energy from wave and tidal energy throughout the world. There are several methods to harvest this energy, such as tidal barrages, tidal fences and tidal turbines. All these methods are based on the same principle used by tidal mills over 1,200 years ago and can be used as clean and predictable sources of electricity.

Things You'll Need

• Tidal bay
• Barrage or dam
• Tidal gates and turbines
• Electricity storage unit

Instructions

1. Find a a suitable area for exploiting tidal energy. Tidal bays with a narrow opening are the best sites for tidal energy. You need a tidal range, which is the difference between the high and low tide mark, of at least 7 meters or 23 feet to build a commercially economical tidal energy generating station. The coasts of Alaska and Washington are ideal sites for tapping into tidal energy.

2. Build a dam across a tidal bay. The largest tidal generating station in the world, which produces 240 megawatts and has been operating since 1966, is located on the La Rance river estuary in France.

3. Install gates and turbines along the dam. When the tide comes in, water enters the gates, turning the turbines and filling the tidal bay. When the tide drops, the gates are opened and water flows out of the bay, again spinning the turbines. Each turbine has a generator that converts the mechanical energy produced by the movement of the turbines into electricity.

4. Connect the turbines to a central electricity storage unit where the electricity can be stored until needed.

Tips & Warnings

• Although tidal energy is a clean source of electricity in the sense that it does not cause the emission of gases, it is not without its negative consequences. For instance, if you change the tidal flows of a coastal area by damming a bay, it can have devastating effects on the region's ecosystem.

References

• Ocean Energy Council: Tidal Energy
• U.S. Energy Information Administration: Hydropower

Resources

• International Journal of Green Energy