No Way to Treat a SSSI?

I am somewhat disturbed to read that there are plans to greatly extend the extent of the proposed power-generating lagoon planned for Swansea Bay before the first stage has even been completed (http://www.theguardian.com/business/2014/feb/06/swansea-bay-tidal-lagoon-power-planned). The place is a SSSI and is important for birds, fish and cetaceans. I really do think that they ought to evaluate whether there are any ecological downsides to the initial development before they greatly expand the whole construct. 'Green electricity' is desirable but not at any environmental price!