I was actually thinking about an alternative energy source from the sea... it would float on the surface and be like a set of interlinked chains in a fabric with dynamos in them that the simple harmonic motion of the ripples of water constantly could be used to create electricity.
Let's suppose out at sea each peak to trough is 60cm and the movement up and down causes the internal dynamo to be driven by 30cm for each one - you probably need two lines into each one, positive and negative serially and you could get a pretty good average amount of electricity probably.
No idea if it would work or the output would be too uneven but there is a lot of sea and it seems a bit easier to build and repair than something that sits statically in the water.