Tidal Power - Feasible?

The main problem with tidal power is simply its intrinsic low duty cycle. Tidal flow occurs only for about +/- 2 hours before low/high tide and at best, you get useable flow for 6-8 hours a day.

In addition, as we will see, there are rather few topographically favorable locations in the world that impound sufficiently high tides. One of these places is in Wales:



The idea is to build infrastructure at these "constriction" zones. On example, a tidal fence, is shown below.



Another example is a tidal turbine but this shows the nature of the problem The turbine pictured below has an output of 1.5 MW but weighs 1350 tons, roughly 9 times more than a 1.5 MW wind turbine.



A typical deployable twin balde tidal turine:























However, worldwide there are only about 20 sites that are suitable for tidal barrage stations.



One Viable Project - Never Done







Bottom Line: There is way insufficient yield:



However, there are some places in the PNW that are being considered for tidal power: