http://www.tidalelectric.com/

 "Tidal Lagoon" solution is that installing pumps allows the lagoon to be used for pumped storage (including pumping OUT at low tide) at several states of the tide, particularly as the lagoon perimeter has to be at a height sufficient to contain the relatively few really high spring tides, plus surges etc.

I'm a big fan of Tidal lagoons, coupled with judicious use of barrages, where tides are not necessarily cut off, but restricted to multiple choke points.

 

"The future is already here -- it's just not very evenly distributed" William Gibson