Originally posted by humy
well, 5% would be a good contributor to renewables at least. Not a bad start! the rest can be made up with other renewables. I think there is a lot of potential for ocean current power ( http://en.wikipedia.org/wiki/Marine_current_power ) which doesn't rely on tides and, of course, has the advantage of being even more regular and predictable than tidal because ...[text shortened]... and steady. But I don't have a breakdown of costs of that either so I don't know how to compare.
But potential is not actual. When they say you can get terawatts from the ocean, you would be talking millions of these devices or more. That is not going to happen. My guess is economics would bottom them out at a few gigawatts max. The power from one nuclear station.
That said, the more diversity in energy the better. The real solution will involve many different kinds of energy from solar to nuclear and everything in between like converting plant cellulose to energy and maybe if we are extremely lucky, cold fusion and even luckier, hot fusion which has several programs researching different ideas there like Tokamak Vs inertial laser and the Z pinch machine.
Personally I think it would be utterly cool if the cold fusion dudes prove to be vindicated, that would literally give power to the people!