> We should be able to get by, happily, on 2000 EJ per year sustained. By your figures, that's less than 1% of what the sun provides. Then at that rate we'd ha

> We should be able to get by, happily, on 2000 EJ per year sustained. By your figures, that's less than 1% of what the sun provides. Then at that rate we'd have 100,000 years of Tidal energy available even if we used it for the totality of our energy needs (and 10,000,000 years if we use it for 1% of our needs as taken in the paper). And that was basically the point of the person you're responding to: it's not so much that tidal energy is non-renewable, the problem is that the paper assume exponential consumption growth, and exponential growth is unsustainable no matter what.