Giant flywheel project in Scotland could prevent UK blackouts(theguardian.com) |
Giant flywheel project in Scotland could prevent UK blackouts(theguardian.com) |
I'm trying to find some stats on this, because flywheel UPS aren't a new idea:
https://www.finning.com/en_IE/products/new/power-systems/ele...
https://en.wikipedia.org/wiki/Flywheel_storage_power_system#...
In the case where a flywheel is used as a UPS, the rate at which it is spinning will vary in accordance with the stored energy.
Large steam/gas turbines running on the grid have a similar effect. Even without hot gas running through them, they can provide rotational inertia for grid stabilization purposes. This flywheel is basically an extremely heavy version of the same idea, and powered exclusively by the grid itself.
You wont be able to ride out a scenario where there is a long-term lack of generation capacity, but this flywheel could buy the precious seconds/minutes required to spin up peaker plants and other contingencies.
From 2016. Apparently part of the charm of flywheel storage systems is that they're always the first of their kind :)
(I suppose you could argue that the Irish one was the first with batteries and this is the first without, but really I suspect neither are either)
* nothing obvious at https://www.nationalgrideso.com/news * minutes from a 2011 meeting suggest that ESO was talking to Beacon Power at the time: https://www.nationalgrideso.com/sites/eso/files/documents/18... * http://credenceturbine.com/business/flywheel-energy-storage-... mentions Beacon Power providing a frequency regulation flywheel in 2014 for a 20 MW plant * "Techno-Economic Assessment of Energy Storage Technologies for Inertia Response and Frequency Support from Wind Farms" 2020 July 02, https://www.mdpi.com/1996-1073/13/13/3421/pdf discusses some details
http://afstrinity.com/company/
I've seen a system meant for hospital ride-through that packed an amazing amount of power into a relatively small enclosure using carbon fiber wound flywheels. For short durations you can get away with this because you're only going to operate one of those. Larger installations would need multiple of those and then you need to get very serious about containment so that if one of the flywheels ever fails it doesn't set off a chain reaction.
The nice thing about the fiber would units is that when they break they self destruct completely within the enclosure. The fiber acts as energy sink by breaking up, as opposed to a steel wheel that will spit out sizeable chunks across fairly larger distances (many meters).
Another player in that market:
https://vyconenergy.com/products/ups/vdc-products/
Grid stabilization is better done using superconductors rather than with flywheels.
Illustrated here in a 1 MW Beacon power system:
https://invidio.us/watch?v=eCtlfj4kMJs
Not all vendor systems incorporate these features, e.g.:
The flywheel disintegrates and turns into a massive spherical weapon of mass distruction?
Like this, but 20x worse?
If it's a 100kw peak electrical machine then it can provide at most 100kw of instantaneous power to the grid while at the same time slowing down by however much is required to deliver that power.
If I understand correctly the idea is a lot like capacitors for DC voltage. The DC voltage has to go down in order for the capacitor to supply current, but the capacitor ensures that the voltage can't go down as quickly as it would otherwise.
https://ww2.energy.ca.gov/2019publications/CEC-500-2019-012/...
20 years ago, there were a couple companies working on flywheel energy storage for mobile applications. They were using carbon-fiber flywheels, which could spin up to 100K RPM, but were expensive to manufacture. I would have predicted (back then) that carbon-fiber would have won out eventually for infrastructure applications as well, but I guess they were not able to get the costs down sufficiently.
I was thinking more about the fatigue of the shaft.
The rest of the world just builds a dam, creates a new lake, and moves on.
I can believe it has "new features" but the underlying mechanics of a Syncon are not new. This may just be something good, being over sold by a company with an interest in boosting.
Life gets difficult for this model because the heat induced due to current 'turbulence' and maybe skin effect gets 'stuck' inside the chamber. Fun engineering problems.
Do we really care if the compressors in the air conditioners and the refrigerators turn at a slightly different rate? Okay, maybe a rapid shift in frequency could be damaging, but a slight drift sounds okay mechanically.
Or am I wrong?
Flywheels store orders of magnitude more power per ton and have very low reaction times (in the order of milliseconds).
This makes them great for frequency control which just means really short term energy storage.
The power grids frequency is directly co-related with the power throughput. If there is too much demand the frequency will drop.
A flywheel can quite easily buffer very short term demands and flatten the somewhat erratic output of wind turbines or solar.
https://www.ianvisits.co.uk/blog/2019/12/10/watch-a-power-st...
"The power plant was notable for being one of the few that could restart generating electricity without an external power to restart its generators in case of a wide-scale power-outage. This was partly due to cold-war concerns that an attack could take out London power supplies.
To be able to restart the plant, it made use of versions of jet engines based on those used on Concorde to jump start the main generators — and they were used to keep the lights on following the October 1987 storms."
My thought is that the weight of the flywheel matters. To be able to absorb / release a tremendous amount of power, I imagine this flywheel would need to be very heavy. If so, wouldn't it non-linearly differ in efficiency from the near vacuum & magnetic bearing designs we've built before?
Perhaps the proposal is to build a large array of smaller flywheels that don't have to deal with the problem I imagine?
I'm not familiar with any part of engineering here -- just a curious soul -- sincerely asking!
There is still a tonne of carbon used in creation...
In the industry these are known as a "Synchronous Condenser" or Syncom. They have been in use for a long time.
https://www.pv-magazine-australia.com/2019/04/06/long-read-b...
One problem with the switch to renewable energy is that the mechanical momentum in steam turbines is lost.
This leaves the grid vulnerable to rapid changes in loading.
http://www.execreview.com/2020/07/giant-flywheel-project-in-...
The Guardian's registration nag keeps getting worse and worse, but there is still a button labelled "Not now" to bypass it.
> Include a "Powered by The Guardian" logo (or such other Guardian logo as we may require from time to time) on the same webpage as any republished OP Content, or any tool or function that is based on OP Content. Such logo must be a reproduction of the "Powered By" file found at http://www.theguardian.com/open-platform/logos, and comply with any special terms set out by us. The "Powered by The Guardian" logo must not be used in conjunction with any content other than the OP Content.
[1] https://open-platform.theguardian.com/
[2] https://www.theguardian.com/open-platform/terms-and-conditio...
(Yes, if we used more hydro-electric then that would do the job for us, but it's not the case that we need this in order to store energy).
https://www.wired.com/2016/05/forget-elons-batteries-fix-gri...
Flywheels contain tiny amount of energy, but can respond nearly instantaneously To provide frequency regulation on the grid.
Hydro has massive amounts of energy storage (days+ worth of output), but takes a looot longer to respond than flywheels.
I think we will see very little flywheel or dam construction in the coming decades; battery storage is becoming cheap enough that it will hit the non-linear inflection point in deployment in the next few years. First, lots of lithium ion, and likely after that lots of flow batteries.
Balmacaan and Coire Glas are in the planning stages and due to start building soon. There's plenty of high land available.
Your wording implies this is better than the flywheel solution - can you elaborate for a layman?
We have mountains (Wales, Lake District, Scotland), but the likelihood of creating lakes for hydro use is close to zero. And you would need many, many, flywheels to substitute for one lake.
In case anyone's wondering what this is about, in the 1960s the Tryweryn Valley in Wales contained a village (Capel Celyn) which was evacuated and the valley flooded to make a new reservoir to provide water for Liverpool. There's a portion of a nearby wall painted with these words.
UK is an island, and you have highlands. Why not make some salt water lakes there?
We're the size of Michigan with 67 million people.
The household electric devices or the long term frequency drift are not relevant there, it's about keeping the huge turbines everywhere else running at a stable rate. The other way to achieve rapid compensation for frequency drop is to disconnect consumers, i.e. automatically triggered blackouts.
Traditionally, the inertia of thousands of tons of spinning generator turbines across the system provided this inertia, but with more and more nonlinear sources (and also nonlinear loads), that balance is disappearing.
Flywheels are useful because they store a lot of energy and don't require a lot of energy to keep them spinning (i.e. topped up with energy). Simply connecting them to a generator can be done (relatively) quickly and allows them to supply power for a relatively long period of time. It's basically a mechanical battery.
Both have the advantage that they are cheaper to operate than a typical peaker plant, which is increasingly the role of remaining coal plants that are otherwise too expensive by orders of magnitudes to operate continuously. Switching those on is a last resort for energy companies. The more battery they have, the less need they have for those. And the less they get utilized, the more expensive they are to keep around. Gas plants are better but they take a long time to turn off and on again and doing that is also not cheap.
Prices have actually turned negative a couple of times in e.g. the UK in cases where the power companies were literally paying people to use their excess power just so they could avoid having to turn off plants that are expensive to turn back on. Basically, grid storage capacity allows electricity companies to smooth out peaks in demand and supply and respond extremely rapidly by either soaking up or supplying many GW.
With flywheels, I don't see the bearings as difficult. I mean it's sure a challenge to keep a few tons afloat, but nothing unsolved. I'd assume (but don't know) that you can scale magnetic bearings a few orders of magnitude with their properties staying the same.
On the other hand, the faster you spin flywheels, the more energy they store. And here comes the limitation: The material they're made of has to sustain all tearing force. So at some point you'll add mass instead of spinning faster.
This all becomes more complex when the loads are switch-mode power supplies and the generators are solar panels. The flywheel project adds some smoothing to the grid, as spinning generators are replaced with DC devices. But the principles are the same; without any extra devices, electricity has to be generated at the exact instant that it is consumed, and the consumers have a large physical effect on the generators.
(Frequency is not proportional to voltage in general, only in this spinning-generator connected to a spinning load case. You can obviously switch DC on and off at whatever frequency you desire, and a perfect on/off cycle consists of infinitely many frequencies at various amplitudes.)
But your main point is correct. This has to store energy to control frequency.
We haven't even burned coal for the purposes of providing power[0] since the 11th of May. That's the longest period without coal being burned since 1882.
[0] Sort of. A couple of coal plants underwent maintenance and had to be fired up and provide power to fully test them. We had a total of around 21 hours of coal plants supplying energy and we're now at day 18 of a coal-free run, and prior to the test we had almost 68 days!
It's like describing a light-switch in terms of relays. Not wrong, not even misleading, but normally you'd expect the comparison to be made the other way around; describing relays in terms of light-switches or the rotational inertia of turbines in terms of flywheels.
The heavier it is also requires bigger more expensive bearings and accompanying system to get the thing spinning in the first place.
I looked at a flywheel that spun at 12,000 rpm. It was going to be located in an underground vault in case it ever got off its pedestal bearings it wouldn’t mow people down.
Like anything that stores energy but doesn’t generate the economics aren’t great.
Yes, because they'd be lochs, not lakes :-)
We already have some (e.g. https://en.wikipedia.org/wiki/Cruachan_Power_Station) and are talking about building more (https://www.bbc.co.uk/news/uk-scotland-highlands-islands-445...).
[1] https://www.google.com/maps/@50.514101,12.8731705,3067m/data...
[2] https://en.wikipedia.org/wiki/Markersbach_Pumped_Storage_Pow...
https://wikitravel.org/en/Welsh_phrasebook
Or rather, the orthography is - spoken Welsh is ancient, but the way of writing it with Latin letters is relatively new, so it was worked out fairly sensibly.
The actual grammar is headache-inducing, though.
However, at least all the letters are familiar. Asian languages are at least an order of magnitude harder for westerners.
When I moved here, I arrogantly stated I was going to learn Irish. I'm humbled now.
But isn't the point that it provides inertia towards stabilizing the frequency? I don't think it matters whether you can vary the energy stored if it's just acting as a, well, wheel... if the goal is to give you a bit more time to bring more generation online or take it offline then it seems like a simple system would be fine. It's not storing power, so it can only ever slow the drift to give more flexibility.
Imagine if one of the motors on the flywheel stopped responding to inputs.
Windmills had governors which were horizontal wheels with two or more pendulums attached to the outer edge. The angular velocity is trying to lift the pendulum and gravity is pushing it back down, so velocity increases much slower than momentum.
The only problem you need to worry about there is seized bearings or foreign bodies unbalancing the load.
There are other devices that replace gravity with springs. You might be able to do the same with permanent magnets. But I believe each of these relies on the device being able to put up with larger strains than the pendulum.
Suddenly all that stored energy wants to go somewhere.
In a conventional plant, the spinning machinery is monitored by vibration sensors. If the vibration exceeds some threshold, a "Turbine Trip" occurs and the offending generator is disconnected from the grid. It then slowly spins down, dissipating energy via it's own friction.
It's a synchronous motor which normally idles at the Mains frequency, but if the Mains frequency attempts to change, the rotor inputs massive amount of current (leading or lagging) into the mains which prevents the change.
There is no need for a drive motor.
In the industry they are known as a "Synchronous Condenser" or Syncom. They have been in use for a long time.
https://www.pv-magazine-australia.com/2019/04/06/long-read-b...
I guess I had assumed -- especially based on the picture and description -- that a portion of the mass of the device was the synchronous motor and that a portion of the mass of the device is just "dead weight" whose purpose is just to act as energy storage via rotational inertia.
The parallels to the steam turbine would seem apt; the turbine end of a generator has a lot of mass relative to the electrical end. Isn't that a part of the point? Or did I miss something?
That means it can spin at any frequency and it doesn't really matter what state the grid is in.
It's a synchronous rotor which is spun by the mains. When the mains frequency tries to change, the momentum of the flywheel supplies massive leading or lagging current to prevent the change.
It behaves exactly as an un-powered generator idling on the mains.
There is no DC motor.
In the industry they are known as a "Synchronous Condenser" or Syncom. They have been in use for a long time.
https://www.pv-magazine-australia.com/2019/04/06/long-read-b...