What once looked dismal now looks more promising. However, all wave energy devices have to have high inertia (mass) to withstand the impacts themselves. This may be a limiting factor in the overall scalability of this technology.

Although its difficult to find the technical data, what I have found, combined with my own calculations suggests this:

• Wind Turbine material cost is 10 kw/ton
  
  
• Power buoy technology looks like, at the moment, has a cost of 2 kw/ton (5 times more material intensive)
  
  
• Optimistic designs exist (from Ocean Power Technologies) for a 500 KW 100 ton, 37 meter wide boy so thats 5 Kw/ton. Given OPT's previous history, this number is probably two high by a factor of 2 > so I would argue that 2.5-3 kw/ton will be the material cost of power buoy technolgy.
  
  
• But note that the Pelamis (sea snake) has a total weight of 750 tons for a production of 750 KW. So that's 1 kw/ton > 10 times worse than wind!
  
  
• New technology tidal turbine (see week 9) is 1.5 MW unit that is 21 m diameter intake tube and weighs 1350 tons! (note a 1.5 MW GE Wind turbine weighs 164 tons)