Can We Get Power From Tides?

With these entire recent scare from earthquake and tsunami (also known as tidal waves), out of the disaster, can we get something good from these tides?

Tidal power is the only form of energy which derives directly from the relative motions of the Earth-Moon system, and to a lesser extent from the Earth-Sun system. Tidal forces produced by the Moon and Sun, in combination with Earth's rotation are responsible for the generation of the tides. Other sources of energy originate directly or indirectly from the Sun, including fossil fuels, conventional hydroelectric, wind, bio fuels, wave, and solar. Nuclear energy makes use of Earth's mineral deposits of fissile elements, while geothermal power uses the Earth's internal heat which comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%) {source: Wikipedia}.

Tidal energy is come from the relative motion of large bodies of water. Periodic changes of water levels, and associated tidal currents, are due to the gravitational attraction of the Sun and Moon. Magnitude of the tide at a location is the result of the changing positions of the Moon and Sun relative to the Earth, the effects of Earth rotation and the local geography of the sea floor and coastlines (brought about by earthquake sometimes affects it).

Because the Earth's tides are ultimately due to gravitational interaction with the Moon and Sun and the Earth's rotation, tidal power is practically inexhaustible and classified as a renewable energy resource (source: Wikipedia).

Thus, a tidal generator uses this phenomenon to get electricity. Greater tidal variation or tidal current velocities can dramatically increase the potential for tidal electricity generation. Tidal power or tidal energy falls under the form of hydropower that converts the energy of tides into electricity or other useful forms of power.

The first large-scale tidal power plant (the Rance Tidal Power Station) started operation in 1966. Although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy. Among sources of renewable energy, tidal power 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 (e.g. dynamic tidal power, tidal lagoons) 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 (source: Wikipedia).

Tidal power can also be classified into three generating methods: 

Tidal stream generator

Tidal barrage

Dynamic tidal power

These methods are gaining in popularity because of the lower cost and lower ecological impact and involve kinetic and potential energy. However, there is still some questions on impact of these methods to our environment as well as its inconsistent price range which makes it harder for other countries to try this alternative.