Severn barrage - sustainable power?

It may seem odd, at first thought, that a green like me would be against a major renewable energy proposal such as the Severn Barrage, but I am. Dont get me wrong though, I am strongly in favour of making the best use of the renewable energy available due to the very large rise and fall of the tide in the Severn Estuary, just not by building a huge barrage across the whole estuary.

Why am I against the barrage idea? What method of extracting energy am I in favour of?

The barrage would be a vast civil engineering project, consuming vast resources. The financial costs alone would be enormous - more than £10 billion. A huge project means huge impacts, particularly environmental ones (the estuary is very rich in bird life and ecolgically speaking is very productive). There could also be huge economic and social costs because such projects are often plagued by huge cost rises due to delays and unforseen problems. Even if there were no delays it would take a long time to build it, but we need to become more efficient and renewable now!

The idea of building tidal lagoons in the estuary to extract tidal energy is a much better one. Tidal lagoons would not cut across the whole of the area. They may well have a postive impact on biodiversity and would not destroy bird habitats. Lagoons could be built a few at a time, each one having a much shorter construction time than a huge barrage. More lagoons could be added, over time, spreading the financial costs and risks.

The issue of being in favour of renewable energy in general terms does not mean being in favour of every single proposal. Its very important to back the project that has the best combination of social, economic and environmental benefits. In the case of tidal energy from the Severn I believe 'smaller is more beautiful' !