Tidal Barrage
Seawater is 800 times denser than air; hence water traveling at 12 mph exerts force comparable to a 110-mile wind. This power can successfully be harnessed, via turbine. Ocean current is of two types, two-way (ocean tides) and one-way (i.e., the Gulf Stream, for example) and can be used to generate electricity. Experts contend the Gulf Stream alone transports some 1.5 petawatts of heat, equivalent to 100 times the world energy demand. A tidal fence (between two land masses) can serve as a conduit for autos and trains (picture a high-speed bullet train linking Miami, Houston, and San Diego, for example). With regard to future water scarcity issues (rivers like the Colorado drying up, drought, etc.), a tidal fence could also be used for transporting desalinated water to shore.
(Tidal Energy).
The largest tidal power station in the world (and the only one in Europe) is in the Rance estuary in northern France, near St. Malo. It was built in 1966.
A major drawback of tidal power stations is that they can only generate when the tide is flowing in or out – in other words, only for 10 hours each day. However, tides are totally predictable, so we can plan to have other power stations generating at those times when the tidal station is out of action.
Wikipedia: Tidal Power
