Tidal power

Tidal power or tidal energy is a form of hydropower that converts the energy obtained from tides into useful forms of power, mainly electricity.

Overview

Although not yet widely used, tidal energy has potential for future electricity generation. Tides are more predictable than the wind and the sun. Among sources of renewable energy, tidal energy has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus constricting its total availability. However, many recent technological developments and improvements, both in design and turbine technology, indicate that the total availability of tidal power may be much higher than previously assumed, and that economic and environmental costs may be brought down to competitive levels.

History

The first large-scale tidal power plant (the Rance Tidal Power Station) started operation in 1966.

Generation of tidal energy

Tidal energy is generated by the relative motion of the Earth–Moon system, with the gravitational fields of the Moon and the Sun both contributing to the size and direction of tides.

Operating principles

Tidal power is taken from the Earth's oceanic tides. Tidal forces are periodic variations in gravitational attraction exerted by celestial bodies. These forces create corresponding motions or currents in the world's oceans. Due to the strong attraction to the oceans, a bulge in the water level is created, causing a temporary increase in sea level. When the sea level is raised, water from the middle of the ocean is forced to move toward the shorelines, creating a tide. This occurrence takes place in an unfailing manner, due to the consistent pattern of the moon’s orbit around the earth.

Tidal power schemes

There are three basic ways to tap the ocean for its energy. These are tidal streams, barrages, and tidal lagoons.

Environmental considerations

The strong ocean currents result in no increase in global warming and no production of greenhouse gases or waste, it has the potential to provide a considerable amount of renewable energy.

See also

• Wave power
• Marine current power
• Ocean thermal energy conversion
• Renewable energy