Summary
There are a lot of schemes being discussed and piloted to derive electricity from the movement of ocean water (waves) but the economic and environmental issues will be difficult to overcome.
Analysis
Ocean power systems, such as the BioPower systems, are claimed to be environmentally friendly with no impact on marine life. At 25 meters for the 250 kW version, the size alone will certainly impact the ocean environment. The 1000kW version will have to be much larger still. And the impact of high voltage cable on the sea floor is also a potential issue due to EMF.
The cost to install and, especially, the cost to maintain equipment on the sea floor or below the sea surface will be significant as will the effects due to the salt water environment.
In some ways, the issues faced by ocean wave power systems will be similar to those faced by off shore wind installations - corrosion, access difficulties, exposure to harsh environments - yet the capacities of contemplated ocean wave systems are much less than their wind counterparts. So, the cost per kW to install and the cost per kWhr to maintain are sure to be significantly higher.
Ocean wave power systems likely have a place in the portfolio of electric power production systems, but it appears to be a relatively small place due to costs and environmental issues.
