I have seen many feasible concepts for harnessing wave energy, using many different basic principles. The technology for "smoothing" out the power flow is not difficult, and transporting large quantities of power underseas is a mature technology that powers many, many island communities.

Critical issues being addressed by researchers include maintenance (a big one), survivability of the system, interference with surface traffic and ecosystems, and simplicity. None of these are insoluble.

The Pelamis concept is a good example of something being deployed now. Its design emphasises survivability and workability, although the efficiency is not as high as some other concepts.