'tis the Grauniad, so take with however much salt you feel appropriate.
"Backers of an ambitious proposal to transform the UK's power supply will learn in the next few weeks if they are to be given the go-ahead to build tidal lagoons to generate electricity. The green light could see a series of major lagoon projects costing more than ukp15bn being constructed around the coast of Britain"
It will be an economic disaster. And probably an ecological one.
I sincerely hope they aren't allowed top suck public money into a waste of time.
I thought that this idea had been buried long ago, not only would it affect wildlife, but also predictions of silting up in other parts of the coast and inside the lagoon could render the ongoing cost very much too high to make anyone invest in it as an on going concern. There have been some others built, at least one in France and I know there have been problems ongoing. Brian
a lot of people stand to make a lot of money out of the taxpayer with these ecobollox projects.
Maybe they should read this first:
"The challenges ahead are formidable as evidenced by a pilot project in
2009 which saw OpenHydro and Nova Scotia Power deploy a 400-tonne turbine that had two of its 12-metre blades snapped off in the powerful waters."I like the idea of tidal power as it is constant and predictable. But will the technology ever be up to it?
It's not constant. It's periodic.
En el artículo , Jeff Layman escribió:
The wrong kind of tide. :)
In message , Tim Streater writes
We've done that bit:-)
Going sideways, how about pension investment in nuclear?
>After Mr Trump has finished his Mexican wall, perhaps he could build one down the north sea and around the English channel, and we could make that the border and use it to generate tidal power? Brian
+1
See my posts on 'Ramblings on Tidal Power' earlier.
This Grauniad article is a re-hash of what has been published previously, except that I note they're now getting a strike price of only £89.90/MWh, compared to £168/MWh they were wanting before. They've obviously been told they won't get the higher price. That they can virtually halve their asking price and still make a profit is a measure of the cynical profiteering that goes on in the renewables industry, all the way from Big Renewables down to minnows like Harry.
They're still putting out that misleading advertisement of 350MW output, when this is only the output at full tidal flow for a brief period four times a day, and in reality its output will be only about
58MW averaged over a year, a capacity factor of about 18%.They continue with the misleading publicity for the output of the proposed Cardiff scheme, claiming it will be 3,000MW, when in reality this output will only occur for a limited period at peak tidal flow, and averaged over a year the output will be a fifth of that, something like 600MW. And it will be intermittent, on-off-on-off etc. four times a day, like a flickering light bulb. With that capacity, it will need the equivalent of Hinkley C to be switched on and off in the intervening periods to compensate. How stupid is that? You'd be much better off just having Hinkley C or its equivalent, running 24/7, no intermittence, and save everyone a lot of money. And of course you'd need the power lines installed capable of carrying that 3000MW peak output from the lagoon, when for 12 hours a day they'd be carrying nothing. Another waste.
Yes, I know you can build other tidal barrages in other places where the tides are out of phase with the Severn estuary, Morecambe Bay being the one often mentioned. But you're going to have to enclose a pretty large part of the Bay to get a peak output of 3000MW, at considerable expense, and why do either when one nuke the size of Hinkley C will produce more than those two together, and continuously. It's just Green stupidity (which I suppose is tautology!).
From an earlier post, the Gibrat ratio, k, is a quick and dirty way of assessing the viability of a particular tidal barrage scheme. It is calculated from the equation k = l/E, where l is the length of the barrage in metres, and E is an estimate of the power available. E is calculated from E = 1.4 x R^2 x A where R is the mean tidal range in metres, and A is the impounded area in km^2 *. The lower the better; good tidal barriers achieve figures less then 1; La Rance in Brittany achieves a k of 0.36 .
However, it's not an absolute measure by which to judge the merits or otherwise of a tidal scheme, only the relative merits. In Gibrat's day, a ratio of less than 1 was considered good, greater than 1, poor. But today, construction costs have changed, as has the price of electricity, so it may be that today, less than 10 is good. OTOH it may be that less than 0.1 is good. It's just a rough way of judging the relative merits of several schemes at any one time, assuming unit costs and financial returns are broadly equivalent for each one.
For the Swansea Lagoon, the barrage length will be 9,650 metres, the mean tidal range is 8.5 metres, the area will be 11.5 km^2 so k = 8.3 (9650/(1.4*8.5*8.5*11.5)) which is relatively poor.
For the Cardiff lagoon, according to the Grauniad article, the barrage length will be 20,000 metres, the area will be 65 km^2, and the mean tidal range will be as for Swansea at 8.5 metres, so k = 3.0 (20000/(1.4*8.5*8.5*65)), which is at least better than the Swansea scheme.
You are implying all other generators do so out of purely altruistic motives? Without a thought to making a profit?
Perhaps the same trick should have been pulled with Hinkley Point.
En el artículo , Chris Hogg escribió:
Something like this would seem to be a better solution: cheaper, doesn't block the bay, constant power, presumably lower impact on the environment (if it doesn't do a Chernobyl). One issue would be a transmission uplink to the grid which would still need to be built.
This caught my eye though: 300MWt and 75MWe. 25% efficiency? Seems very low. What about primary containment, and corrosion caused by seawater?
More:
Some controversy in Russia about it:
Of course not. Reasonable profit is perfectly acceptable. And I also accept that with relatively novel and untried schemes such as renewables, if the government wants investment in those schemes (rightly or wrongly), it has to provide a carrot, such as the £305/MWh for tidal streaming in the Pentland Firth for example.
But I object to profiteering at the consumer's expense (and so should you), especially when the presentations are deliberately misleading to exaggerate the power that will be produced, to fool the general public who can't be expected to know better. I just hope that the technical people who advise the government on the merits of such schemes are alive to these exaggerations.
Not sure who you mean should have pulled the trick; EDF or the government? If the latter, how do you know they didn't? In comparison with the strike prices for renewables, the strike price for power from Hinkley C is very reasonable.
It may be predictable, its certainly not constant.
And its not very predictable if it snaps blades off...;-)
Oh, and by the way, consumers may spend their money on things they 'like the look of' but its traditional in engineering circles to spend cust9omers money of things that *work* and *make money*.
Which is why Anthony Gormley doesn't design power stations.
Id does give a first stab at relating 'amount of energy stored per tide' to 'cubic kilometers of concrete needed to make the barrier.
circular bays with narrow mouths being the best.
Very high, to me, given its tidal, not pumped.
And the head is very low indeed.
The Achilles heel of tidal power, like all renewables, is intermittency. It may be more predictable than wind and solar, but it still has to be compensated for, by supplying yet more intermittent and inefficient power elsewhere to coincide with the gaps. Oh, and tidal power isn't that constant either. It varies across each tidal cycle from nothing to a peak and then back down again, and the peaks vary in strength with a two-week cycle between spring and neap tides.
I notice in the Bay of Fundy article the usual reference to the maximum power output of the turbines, when in reality it will be something like 20% of that when averaged over 12 months, due primarily to intermittency.
Nuclear doesn't suffer from intermittency, except perhaps when governments such as Merkel's get involved!
Err ... it's a floating nuke
Oh. That one. Well 37% is top thermal efficiency on most steam turbine plant with BIG condensers, so 25% sounds OK for a steam turbine built to actually *float*.
And not be too massive.
Perhaps now all those tidal power supporters would like to pile in and show why Chris is talking c*ck. With numbers please - so if you can't do sums don't bother.
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