On 18 Oct, 17:20, harry wrote:

We have the world's best site for tidal power, ie the Severn estuary.

No-one has really discussed the Severn estuary for tidal power. The
schemes put forward have been in the Bristol Channel, which is
downstream of the estuary, enormously wide and an impractical scale
for anyone except the Chinese to contemplate barraging.

The Severn estuary is an awkward river. It's not as big as you might
imagine: although very wide it's also very shallow across almost all
of this width and there's only a narrow navigable channel, which both
tidal and shipping needs would be fighting over. Tidal flow turbines
in the narrower part of the Severn (even the Usk, Wye or Avon) would
be an interesting idea and far cheaper than a barrage on the Severn,
but the effect on navigation would make them most unpopular.

I'd like to see tidal flow turbines in the Bristol Channel, but free-
flow turbines, not a barrage.