The challenges posed to any electricity grid by ever more intermittent sources of power in the fleet are well known. The UK grid (and others) is not bereft of means to deal with this - at a cost, and specifically a cost from which the said intermittent sources are shielded. Indeed, advocates of renewable energy have largely been allowed to get away with putting their fingers in their ears and chanting LahLahLah on the subject for years.
There are two basic challenges, and grid has consistently expanded its toolkit to meet them, with plenty more ideas yet to be implemented. The 'immediate' issue is the occasional instantaneous fluctuation that threatens to upset the frequency of grid output: the longer-duration issue is the near-complete non-availability of wind and solar power on other occasions, including just those times when they are most needed. The ever-reducing amount of fossil-fuelled power available to the grid impairs its ability to respond to both challenges - but it still gets by[1]. The difficulties shouldn't be overstated, even as the costs shouldn't be understated.
Anyhow, it seems there's a new game in town. One of the many ideas that have been floated over the years is the use of the good old-fashioned flywheel, and it seems the grid is going to give it a go. (It only addresses the 'immediate' issue, by the way: of technologies currently available, only gas-fired power can systematically address the dunkelflaute, now that we have no more coal-fired plant.)
My question is: do we have any physicists or power engineers out there who can comment? Some of these bright ideas turn out to be fads / daft / complete duds / ludicrously costly / several of the above[2], and personally I don't have a view[3].
Over to t'readership.
ND
___________
[1] To an extent once considered theoretically infeasible. Ah, the perils of academic a priori reasoning ...
[2] Using hydrogen for the longer-duration issue comes to mind
[3] I will, however, suggest that the putative savings the grid claims it will make using these flywheels - "£14.9bn between 2025 and 2035" - fail the basic do-we-believe-this? test by a long way. FFS!
42 comments:
Yes, but you probably won’t like it.
One of the best solutions to consumers of reactive power presenting their demands to the grid (and thereby requiring sources of reactive power which is increasingly costly to generate) is to simply price them off the grid.
Quelle horreur! I can quite picture your expression now at such a notion. But hear me out. For years, reactive power consumers have been freeloading off of other loads.
They’ve been let off paying their way due to their making an inherent demand for a product (and creating a blocker to product development and enhancement through their insistence on their legacy product being continually supported despite a steadily reducing user base). So, now they have to pay up. In commercial electricity tariffs, high reactive loads are already differentially priced. So this just needs to be widened and deepened.
To get to the technical bit, which I’ll have to abbreviate for the sake of the length of this post, most reactive power demand comes from 3-phase motors. Improving motor controls, especially with variable frequency drives, reduces reactive power consumption (in effect, when you turn on a motor, for a few milliseconds, it’s effectively a dead short on the line). Variable frequency drives are more expensive than the usual soft-start controllers. But they reduce reactive power needs. Incentivising better power control systems through the price mechanism seems the right way to go.
Of course, those who previously enjoyed a subsidised supply but now have to pay their way will surely whinge. But isn’t this what capitalism is all about?
I loved the paper edition of the Telegraph's headline about a "roll-out" of flywheels. I pictured flywheels, in certain knowledge that they are born free but are everywhere in chains, making a mass roll-out over the countryside, demolishing everything in their paths. Like Day of the Triffids but worse.
Maybe the flywheel sites will be surrounded by lots of anti-tank guns, ready to destroy any flywheel that makes a dash for freedom. Or maybe flywheels will be installed on old oil and gas platforms so that it's the fishes rather than us who must worry. Or install them up highland glens, which can be provided with huge trenches across their mouths to trap the flight-for-freedom flywheels.
If anyone knows, could he tell me whether the flywheels are intended to rotate about a vertical or a horizontal axis?
Come to that, how are the flywheels to be protected from the occasional earth tremor?
You know, I think I might prefer fracking in our neighbourhood to huge flywheel sites. But not both, please.
" I pictured flywheels, in certain knowledge that they are born free but are everywhere in chains, making a mass roll-out over the countryside, demolishing everything in their paths."
I give you Panjandrum, one Britain's less successful wizard wheezes from WW2:
https://www.military.com/video/operations-and-strategy/second-world-war/the-great-panjandrum-scares-a-dog/1123500263001
Think of the rubbing of hands and smiles in China and India at the thought of all that steel that the UK will have to buy. To get enough energy so that the generator lasts for an hour, or two, will mean a huge/heavy flywheel. If anything breaks, or if the control circuit goes 'phut', I hate to think of a flywheel going on the loose.
Clive - many thanks.
Systematic over-specification is a perennial issue. The classic is water: all water in (our) system is potable - but how much is drunk?
As regards electricity, the joke is that the manufacturers / scientists etc who require really hi-spec electricity, every time, make sure they guarantee it themselves by one means or another. So the grid really is over-specifying.
What do these phenomena cost us? And, yes, "capitalism's answer" (if capitalism were a political movement, which it ain't) would tend to be: drive regulation in a different way - to make the parasitic buyers pay for what they want / need
Yes, the problem of storage/balancing is traditionally addressed by saying "we'll use big batteries, or hydro, or hydrogen" - none of which are anywhere near actual productive use, or haven't been developed at acceptable cost, or are (hydro) physically impossible due to a shortage of suitable valleys.
Good thing we've still got some available gas. And talking of which:
"The International Energy Agency (IEA) views the risk of full stop of Russian gas supplies to Europe via Ukraine as significant after 2024 and includes it into its forecast for the gas market in the next year."
"...any flywheel that makes a dash for freedom..."
Actually this is a scenario that really needs to be thought about. Any flywheel with sufficient angular momentum to be useful will necessarily be enormous, and will therefore represent an enormous amount of stored energy. Any kind of failure, physical or control, will be catastrophic. A bit like giant Li ion batteries, really...
Whatever, I expect once someone actually does the sums (do we have anyone left who can do sums?) and finds the whole idea beyond ludicrous, we'll never hear of it again.
When, if ever, will we come to our senses? But despair is a sin, as Jerry Pournelle used to say.
Our company did some work a few years back for an outfit called Isentropic. They were (at the time) a new startup exploring the possibility of grid scale energy storage using thermal storage of electricity. The basic principal used heat pumps in a reversible process storing energy in insulated containers filled with rocks!
It's a slightly different proposal than using flywheels, the advantage of which is the ability to dump large quantities of energy into the grid at short notice. The company seems to have gone quiet so perhaps they found some technical difficulties that they couldn't overcome or maybe found that it wasn't an economical proposition?
PMacF - @ Any kind of failure, physical or control, will be catastrophic. A bit like giant Li ion batteries, really...
Too right. AFAIK, there's only been one really big LI battery fire, in Australia (one of Tesla's), away from built-up areas. But in densely-populated UK and elsewhere, these big grid-scale batteries are proliferating like crazy - and not in remote areas, either.
Not my area of technical expertise at all: but strictly as a layman I'm guessing Sod's Law will mean that one day something dire will happen - and when it does, it's clear from all accounts it'll be truly dire
We all need to remember the successes of technology, though: it's trivially obvious that flying is potentially dangerous, but few give it a moment's thought and the accident stats are very favourable. Ditto nukes. I doubt I'll be getting nightmares about rogue flywheels
(not withstanding that when I was a local councillor on the Road Safety Committee, we had a ghastly case where a bloke on a road crossing was hit by a tyre that had rolled / bounced half a mile down a road (a hill), and killed him outright ... to our eternal collective shame and disgrace, it must be said that some people laughed when the account was read out)
The JET fusion reactor in Culham had a large fly wheel on site. It was charged up before the reactor was turned on to limit the draw from the grid during the pulses. Now the reactor has been shut down they were considering using the fly wheel to help balay the grid (not sure if it is operationally doing that yet).
*balance the grid....
The Jet flywheels are a good place to get a feel for scale. Jet has two flywheels each 775 tons rotating at 225 rpm and each stores 3.75 gigajoules. The slow speed suits the dc generators that drive mega amp dc currents into the torus. The power output is stated as 400 megawatts, but that is only for 10 seconds.
To store 400 megawatts for an hour would need a system 360 times as big - or turn faster.
The energy storage is proportional to mass and proportional to the diameter squared and the rotational speed squared. So double the speed and you get four times the energy storage. Similar with the diameter of the flywheel.
The design choices are to rotate fast - say 50,000 rpm or more - in a vacuum and spin a bar or wheel made of kevlar or titanium or maraging steel (we're in that territory).
So the optimisaion involves how much energy storage and for how long. Dunkelflute timescales quickly become out of all reason.
The problems/economics get a bit complex. A very high speed means DC generation to extract the energy and a large inverter to push out 50Hz to the grid keeping the frequency constant as the flywheel slows down. Flywheel designs are a 'bicycle wheel' (mass on rim) or a bar design. Bicycle wheels will fly apart at high speed but bar designs don't store so much energy for a given speed - but will stand higher speeds and a vacuum solves the windage problem.
All this is well known and many examples are available - so 'pathfinder' phooey, this is a good way to extract money from politicians. There is no cheap way to store multiple megawatt-hours. It's the hours that make the difference. Don't expect a cheap result.
Thanks, Anon - very helpful.
Of course, flywheels are only advertised as contributing to the 'immediate' frequency issue (see post) and so they don't even need to release energy for even an hour. Maybe only seconds. As you say, anything longer is completely out of the question, and contributing to a week of outright dunkleflaute just a ludicrous idea.
It would be interesting to see the pro's and con's vs alternatives, which these days are gas-fired spinning reserve - the very thing they're trying to wean themselves off; batteries (which the grid seems not to favour when push comes to shove, nobody quite knows why); and pump-storage hydro.
surely keeping a couple of strategically placed gas stations on standby has to be cheaper than the existing network of diesel plants scattered all over the place.
"Backup generators are used at over 250 NGET sites across England and Wales, the majority of which are diesel powered. These systems provide NGET with the resilience to recover from a loss of supply event."
That was in 2022, when a tender went out for possible low-carbon replacements for these plants. I imagine few or no feasible responses were received.
https://www.nationalgrid.com/national-grid-call-out-industry-find-low-carbon-alternatives-back-diesel-generators
But... I don't know exactly how the grid works in terms of connections, load balancing etc. I tend to assume it's no easy job to get highland wind power to London for example.
Holidayed in Cornwall by huge turbines at Delabole, 2.3 mW each. Quite noisy things, like having the dishwasher on full time. Noticed that quite often only 2 out of 4 were working, sometimes only 1. Seems crazy that there's seemingly not a way to use the "excess" power.
https://en.wikipedia.org/wiki/Delabole_wind_farm
But even then ... 9.2 MW absolute max, from things 300 feet high plus another 105 feet for a rotor blade.
Ratcliffe, just closed, was over 2,000 MW at full capacity. That's 200 Delaboles and it ran 24/7.
@ keeping a couple of strategically placed gas stations on standby
Anon - not quite as simple as that, I think. Today, that's easy - because we have a whole-nation gas industry of critical mass. But if (IF !) gas is to be phased out, somewhere down that process, critical mass will be lost. At which point, how easy is it to maintain those standby stations, with a supply chain etc? Clearly not impossible - but at what cost, in terms of mostly-idle infrastructure of a general nature? Today, the only cost is rewarding the gas stations for their annual inactivity for 300+ days: the infrastructure is all there and in constant use.
Full diesel infrastructure is (a) also there today, and (b) infinitely less onerous to maintain, even if diesel vehicles etc are largely phased out. Every two-bit "developing nation" has loads of standalone, standby diesels. Hell, you can fuel them with a bucket!
The standby gas thing - which is indeed part of Ed Miliband's fatuous 'strategy' - reveals a problem that I reckon is so big, nobody wants to confront it: namely, how the vast UK gas industry & its infrastructure & huge capital value is to be run down and de-commissioned in an orderly fashion. A post on this soon, I think.
It was only a few weeks ago that a bunch of scientists, by no means all eco warriors, wrote to Miliband saying "don't go large on CCS ", and here he is today, with 22 billion for it.
We may as well spend 22 billion on reopening the mines, digging out the coal than chucking it back down the shaft.
I seem to remember from A level Chem a thing called "enthalpy", and drawing a lot of diagrams to work out which reactions would work without energy input.
If we could just capture the carbon from the CO2 at Ratcliffe, say, then we could defy the laws of thermodynamics and burn it all again the following day!
In terms of safety, might they use a superflywheel? They tend to fail in a much less spectacular fashion.
https://www.youtube.com/watch?v=LklUVkMPl8g
9min 48 sec into this video
It seems that Ireland has a working flywheel!
Flywheels dangerous..... LI Ion batteries super dangerous.
But none so dangerous as the clearly deranged Miliband Minor...
The Irish flywheel is interesting: but also featured in that vid ...
... the Irish plan to become Europe's biggest hydrogen economy is, errr, pure blarney
> surely keeping a couple of strategically placed gas stations on standby has to be cheaper than the existing network of diesel plants scattered all over the place
National Grid has a multi-tiered and complex Balancing Services system (3 classes of Frequency Response and many classes of Reserve Services), and I don't think spinning reserve and other quick standby are viewed as competition to (cheaper and slower startup) diesel backups.
Diesels would be competitively contracted as part of the "Fast Reserve" (upto 2 mins startup, sustain at least 15 mins), "Fast Start" (upto 7 mins startup, sustain at least 4 hours). or more likely Short Term Operating Reserve (upto 4 hours notice, sustain at least 2 hours). Basically these are orchestrated to sustain the system until another big plant has time to be started up.
The best document I've come across describing this, though a bit dated from 2009, is:
https://web.archive.org/web/20111223080101/http://www.nationalgrid.com/NR/rdonlyres/32879A26-D6F2-4D82-9441-40FB2B0E2E0C/39517/Operatingin2020Consulation1.pdf#page=75
"Appendix D Description of Balancing Services", PDF page 75
Long ago when we first lived in South Australia an engineer told me of an exciting event a few years previously. They damned near lost all their generating capacity, the saving grace being a little Honda generator.
Their longer term response was to join S.A. to a grid with the state of Victoria (which I assume was already joined to NSW).
We can't save the day by joining our grid to a continental one because we would be bloody fools to trust the buggers.
Well we already have! - joined our grid to the continental one - & comprehensively, too. There's a complex agreed set of rules governing how it all works
And at the end of the cold, windless day, as you say, we *can't trust them*. Works well most of the time, though, it has to be said. But it's the old, old debate: where's the optimum between wasteful self-sufficiency and cheap, flaky dependency. There's no single, or 'scientific' answer.
Unclear Kier
Goodness. Do I have to spell it out. The point of Green is not to save the planet. It is to destroy capitalism and inequality by making all of the 'plebs' equally poor.
The future's shite. The Future's Orange. Remember ?
(How prescient I was.)
Even Spectator readers have been convinced that heat pumps defy the first law of thermodynamics.
I have been made an instructor for a certain listening service, can you believe it ???
I have been made supervisor in a fucking S*** shop for chrissakes !
All I can say is that Britain must be going to rat shit if I'm go-to for such things.
Yet more foolishness - we are apparently locked into a requirement (Tory policy) for car makers to sell yet more electric cars - yet sales are plummeting and diesel sales booming . Now manufacturers are saying only big subsidies (from us, of course) on electric car sales will balance the books.
https://www.theguardian.com/environment/2024/oct/04/carmakers-ramp-up-pressure-on-chancellor-for-ev-sales-subsidies
"the UK bosses of BMW, Ford and the Land Rover-maker JLR were among those who wrote to Rachel Reeves on Friday ramping up pressure for government subsidies for EV sales amid a race to comply with the UK’s zero-emission vehicle (ZEV) mandate. The initiative is aimed at managing the phase-out of new petrol and diesel car sales, and the switch to EVs, over the next six years...SMMT figures showed registrations of new diesel cars for private buyers in September grew by about 17.2% compared with the same month in 2023. That compares with a rise of approximately 3.7% for pure battery electrics."
If nothing else, I'd be tempted to buy a couple of diesels with a solid engine and a decent body, because they'll be like gold dust after 2030, when pure petrol and diesel car sales will be banned.
I know we send electricity to and fro. But I still wouldn't trust the buggers if things got really bad. Though I suppose we could threaten them with a Nordstream-like experience aimed at whatever their vulnerabilities might be.
I suppose our fall back position in the event of a great generation shortage is to turn off the power to all government buildings.
Getting back to spinning mass, a big turbine is about 250 tons and generator rotor similar spinning at say 1500 rpm. A LOT of stored energy and made of steel and copper - with a generous overload characteristic. Those running the system have some slack to play with, the lines and transformers are similarly generously designed, you can overload for an hour and survive. Plenty of time to fire up diesels and gas reserves.
But invertors for solar and battery and wind are not quite so generously rated, you cannot 'overload' an inverter by much, the electronics will stop you doing that. You build it big or not at all. A cascading failure of the inverter switching elements means no more inverter within microseconds.
This means asking a political question - how much Politician - are you prepared to pay to be 'sure' 1/5th of London - or Birmingham etc - will not go dark for an hour once in say 5 years.
Progress is the exchange of one inconvenience for another.
I keep an eye on https://grid.iamkate.com/ to see how our majestic parade to Nirvana is progressing. One thing I have noted is that the %age provided by interconnectors has got bigger and bigger of late.
19.3% at the moment, and on a sunny morning with some wind, renewables only have another 59.1% to go to reach Nirvana.
Praised be Miliband, he shall lead us forth into the new land. Moses, get your coat
Inland of the gorgeous North Coast of Cornwall are lines of aged turbines looking the worse for wear. Many often inactive. An industrial scrapyard in reality. One assumes that no costing has gone into NetZero for the replacement of these - 25 years max, much less off shore.
To drone on.
The big advantage of big spinning multi tonne turbine/generator plants is they give you instant energy - no need to wind up the steam (for a few minutes). That instant energy availability does not come from wind or solar unless you massively over provided the windmills (and the wind is blowing) or solar (and the sun is shining).
Which means there is some lower limit below which you cannot remove big spinning generators - nuclear or gas without risking stability - aka part of London/Birmingham going dark.
Which means building more nuclear or gas (or coal) generators or spreading a great many smaller spinning mass storage systems around the country. Remember spinning mass storage only stores (and costs money) - it does not produce. This implies a suitable mix of generation types must be built in lockstep with renewable generation types. Which further suggests it may not be worth building much spinning storage at all. Time for quadrille paper and pencils.
But in densely-populated UK and elsewhere, these big grid-scale batteries are proliferating like crazy - and not in remote areas, either.
ND: too right. I'm in Lincolnshire which is in the process of being covered over with solar panels - there'll be two solar farms c. 7000 acres each, within a few miles radius of here. One of them will have, reportedly, 324 full size cargo containers filled with Li ion batteries, so presumably the other will too. If that lot goes up, this part of Lincolnshire (which has a gently rolling landscape of great beauty) is going to have a bloody great hole in it and a helluva lot of deaths.
it's a ghastly cliche, but - great thread, folks!
thanks for the inputs - I know more than I did two days ago, which is never to be sneezed at
jim - "risking stability - aka part of London/Birmingham going dark"
I think they'll take out all of Sussex and Hampshire before any of London goes dark, and Hereford and Worcester before Birmingham.
It's not 1974 any more, when we'd sit in candlelit pubs enjoying handpulled beer - happy student memories of the three day week. I think there'd be looting/rioting.
Anyone know what the pollution would be from a major battery plant fire?
Ex-student loved the candlelit pubs in the middle of Oxford; and the fact that some of the streets had gas lighting. I recall 4 dinner jacketed students having a meal on a picnic table under one. Also highly amused by the "why don't you 'eff off" attitude of striking Didcot Power station on the arrival of student Lefties to picket with them...
https://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010106/EN010106-004090-DL2%20-%20Edmund%20Fordham%20EF15.pdf
The introductory summary makes interesting (?) reading. Where's me noddy suit? Or should I just move?
A bunch of Finns;
https://polarnightenergy.com/sand-battery/
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