[redpoint5]

I don't get the theory of operation, unless it's simply utilizing the currents from tidal change. Figured the most efficient tidal systems would utilize the change in height, not the flow.

Probably the best system would be a dam blocking flow (in either direction) in a cove.

... the thing I like about tidal power is it's completely calculable and dependable. One can know when and how much the tides will fluctuate, calculate how much power any given design will produce, and then figure out if it's a viable product. The viability should be calculated to a high degree of confidence before a single thing has been manufactured.