I've always thought that in-stream tidal generators are a much better proposition than barrages, and they can be installed in many more places than barrages and a much more predictable than wind power. It seems the tech is not too hard to crack:
http://news.bbc.co.uk/1/hi/northern_ireland/7790494.stm
Could'nt agree more & I would have thought even the 'protuberance' above the water level could be done away with.
Would'nt mind investing in something like that.