The Oil Drum

Nick,

Interested to know your view on the Severn barrage. In principle I am in favour, though I think that possibly a larger number of smaller schemes strung along the coasts of the estuary may provide a similar power output, at lower cost with fewer environmental issues to overcome.

I am thinking of schemes that would look similar to the Cardiff Bay barrage, but which would have sluices and turbines thus allowing water in and out. There are numerous bays and other sites along both shores where this could be done.

In addition, a number of smaller schemes would have the benefit of being relatively quicker to build (and therefore finance) and would ease the perennial British problem of failing to keep anywhere near budgets and timelines on large-scale projects.

A further benefit of building along the coasts rather than across the estuary would be too avoid the cost of building across the deep water channel in the middle of the estuary. Presumably hydrodynamic forces are greater at greater depth and therefore exponentially increase costs?

A negative side effect of this would probably be to increase velocity of water flow in the newly-width-restricted estuary but this would provide an opportunity for installation of marine current turbines. That said, the new impoundments should also be able to double as flood defence along the shores. I am not sure whether this would increase flood risk further up the estuary, though intuition suggests it might...