OT: La Rance - peak power ?

Tim Streater used his keyboard to write :

It could be only when it is actually generating, it generates that avaerage. It will not generate constantly.

Whatever the original back-of-envelope calculated output was, the actual output is usually less because the introduction of a barrage changes the tidal flow to less than naturally there used to be, oh perfidious nature.

According to

Yes, Wikipedia has that number too.

I was interested because during the so-called petrol shortage, there have been a number of letters to the Times about energy, some of which were pushing tidal power. Today's Times has an actual sensible letter from a Prof of physics at Queen Mary Uni, London, in which he points out that La Rance is producing 57MW or, if that were in the UK, about 1 watt per person.

Matthew Parris, another who apparently can't Do Sums, thinks the tidal flow of the Thames could be harnessed. The prof shows that this would produce around

It'd let you charge your mobile phone once every fortnight, or so ..

A few weeks ago there was a typically green article somewhere promoting the addition of turbines to a weir in the Avon running into Bristol. I was fairly dismissive at first, but on looking closer it seemed to have a capacity of 100kW or so (presumably with winter rainfall) so while not earth shattering, it was probably worth doing, especially if associated with local high insulation new build.

Apart from which the turbines would soon get clogged up with wet wipes and tampons.

soemthing similar was done in Guildford on the river Wey. Probably only about 2m head,

There's also this,

Where was that?

Strangely they didn't implement a proposed Archimedes screw generator (as used at Eton to provide green power for Windsor Castle) when they replaced the sluice gates at Walsham and are now building a separate fish/eel pass, when the screw would have been relatively fish friendly and provided much of the structure for the fish pass.

There are a couple in Ludlow - generating enough for 45 houses.

No. I think tidal is more peaky than that

So 100 of them would produce enough for the UK's entire domestic energy needs (or something - crude guess)?

Are ye mad? Where d'ye get that from?

Is that the one you can drive across the top of, if it is I went there some years ago. Its a very big engineering project and seems to me to be a lot of environmental disruption for not a great deal of power when you consider the de silting and other long term costs. Brian

There was once a plan to use an area called 'The Race' between two of the channel isles as a tidal power source but the habitat disruption and the potential for actually changing erosion and sandbanks over time meant it was never built. I thought at the time that the tide would simply find another way around, its what you might call bleedin obvious!

Brian

And it would be intermittent, and we don't have suitable estuaries. There's a reason why there are so few tidal stations in the world.