Tidal Power or Tidal Energy is an old upcoming energy form, still unknown for global market, but one of the oldest forms of energy used by humans, and is also more predictable than sun and wind energy. It is the future generations energysolution. Tidal energy has not been in much use because it is a new upcoming technology, still has high costs and needs time to find sites with sufficiently high tidal ranges or flow velocities.
Tidal power is reliable and non-polluting as it does not cause emission of gases or use fossil fuel generated electricity, and decreases the need for nuclear power. The system is like windturbines but undersea turbines, driven by the sea instead of the wind (see photo below). Unlike wind and waves, tidal currents are entirely predictable. Tidal energy can be used:
* By building semi-permeable barrages across estuaries with a high tidal range
* By harnessing offshore tidal streams as electricity can be generated by water flowing both into and out of a bay.
Atleast a seven metres tidal range is required for economical operation and for water suffency. It is extremely important to choose right location for tidal energy as it can disturb aquatic and shoreline ecosystems, as well as navigation and recreation.
Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The incoming water was contained in large storage ponds, and as the tide went out, it turned waterwheels that used the mechanical power it produced to mill grain.The earliest occurrences date from Roman Times. It was only in 1800 that the process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe (Source: Wikipedia).