Wind Farms.

[Boundary Layer]

They've proposed such a solution for generating power in the Bay of Fundy in Nova Scotia, Canada - it has the largest tides in the world. I think it has been estimated that there is potential to generate over 50 gigawatts there (if my memory is any good) but they've met a lot of opposition from the fishing industry, particularly on the impact it might have on lobster catching (though, I fail to see how). ...no solution ever pleases everybody it seems, but i think it's a great idea.