OT: La Rance - peak power ?

[Tim Streater]

La Rance, that tidal energy station in France, produces an average of 57MW of power. Does that mean its peak is 114 MW?

[Harry Bloomfield, Esq.]

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.

[N_Cook]

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.

[John Rumm]

According to

the installed capacity is 240MW... so in the grand scheme of things a

25% load factor is not that surprising.

[Tim Streater]

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

0.1 Watt/Person.

[Andy Burns]

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

[newshound]

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.

[Andrew]

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

[charles]

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

[Chris Hogg]

There's also this,

or which is a powerpoint-type presentation and goes into detail about the operating procedures designed to optimise the power output. Until recently it was the largest tidal power station in the world, but it's still miniscule in comparison to say a modern coal, gas or nuclear power station. Tidal power is only for those who can't do sums (which unfortunately is an awful lot of people!).

[AJH]

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.

[alan_m]

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

Floods caused damage that took months to fix.

[The Natural Philosopher]

No. I think tidal is more peaky than that

[RJH]

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

[Tim Streater]

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

100 would produce 5.7GW, against current demand of 35GW.

[Brian Gaff (Sofa]

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

[Brian Gaff (Sofa]

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

[Chris Hogg]

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.

[Chris Hogg]

[The Natural Philosopher]

1000 is more like the mark, with electrc cars, plus a few windmills & solar panels. There wouldn't be anywhere to live and certainly not to enjoy a beach.