> these various wave generators we see in discussion for off-shore use When it comes to wave power, "in discussion" is the operative word. Modern pelton wheels

> these various wave generators we see in discussion for off-shore use When it comes to wave power, "in discussion" is the operative word. Modern pelton wheels are 95%+ effective in converting kinetic energy into mechanical energy and have been in operation for decades. They are super well understood and optimized and are deployed at scales of dozens of megawatts per unit. Total installed capacity is probably into the hundreds of gigawatts. AFAIK, no wave power project is above 10 MW as of now and the total installed base is still tiny despite decades of research. Look at https://en.wikipedia.org/wiki/List_of_wave_power_stations https://en.wikipedia.org/wiki/List_of_wave_power_stations for example. It is a combination of the ocean being a super unfriendly environment for technology in combination with all of the wave energy extraction technologies being extremely inefficient.