The tides moves a huge amount of water twice each day, and finding an effective and economical way to harness that process could provide a great deal of energy. In fact, tidal power has potential for massive future electricity generation, as the tides are far more predictable than wind energy and solar power.
However, although this energy supply is reliable and plentiful, converting it into useful electrical power is not easy.
In the past, a huge dam was built across a river estuary with the flow of the tides used to turn a turbine which turns a generator shaft and electricity is generated – much like a hydro-electric scheme, except that the water flows in both directions. The aim of tidal generators is to take advantage of both incoming and outgoing tides.
The technologies, economics and drawbacks associated with tidal power are very similar to those of hydro power: – earthmoving, dam building, flooding land, placing turbines in dams. The set up costs are significant.
Concerns about the impacts of tidal power dams have caused recent endeavours to focus on tidal turbines and tidal fences. Tidal turbines can operate with tides and currents some distance from land, like underwater wind farms and should have minimal environmental impact.
However, tidal power tend to be situated where tides and currents dictate rather than where the needs arise and at the moment these forms of power generation are still very much in the developmental stage.