Actually I'm 100% in favour of harnessing the huge tidal potential of the estuary. Also the barrage and its knock-on effects would be hugely beneficial for Cardiff and South Wales as a whole! But the question still remains about harnessing the correct technology and limiting the negatives as much as possible, instead of blindly rushing forth and picking the first bright shiny thing that's put in front of you! It's a bit like why we chose the inferior petrol engine over the diesel engine in the beginning of the 20th century, or the fact that Diesel was originally looking into getting them to run on vegetable oil instead of, well, diesel. The rest, as they say, is history... Already the barrage plan has changed significantly because of this massive scrutiny, which is definitely a good thing. But is it even the right plan in the first place? This thing isn't something we can just take down again if we decide we don't like it...