To free the Baltic grid, old technology is new again
spectrum.ieee.org
spectrum.ieee.org
The reaction speed was something to behold. The event happened at 14:05 CET, at 14:09 CET the Transmission System Operators (TSOs) were in teleconference but by then some 1.7GW capacity in France and Italy was dropped and 420 MW and 60 MW was activated in the Nordic and Great Britain. Customers barely felt it: only 70 MW in the North-West Area and 163 MW in the South-East Area were disconnected. By 15:08 the event concluded.
Yes, there was a mistake in the processes which led to the event in special circumstances but , I believe , the respected readers of HN know this all too well , the big question is what happens when an emergency hits. And those processes held up spectacularly.
> Europe’s grid, which is usually connected from Lisbon to Istanbul, split into two as the northwest and southeast regions struggled to keep the same frequency. The problem originated in Croatia and led to the equivalent of 200,000 households losing power across Europe. Supply to industrial sites was cut in France and Italy.
> Transmission grids need to stay at a frequency of 50 hertz to operate smoothly and any deviations can damage equipment that’s connected. Had the frequency swings not been reduced within minutes, it could have caused damage across the entire European high voltage network, potentially causing blackouts for millions.
> A fault at a substation that caused overloading on other parts of Croatia’s grid has been identified as the cause of the issue, network operators concluded Tuesday.
> “The problem isn’t posed by growing green electricity directly but by shrinking conventional capacity,” said Eglantine Kuenle, chief electricity systems modeler at the EWI Institute of Energy Economics at Cologne University. “The upshot is a gap in secure power generation and grid balancing that must be fixed.”
https://web.archive.org/web/20230621192146/https://www.bloom...
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Personal thoughts. I knew we had an interconnected grid, but I had no idea it span from Portugal to Türkiye, nor that the rest of Scandinavia wasn't connected. For a system as critical, and as complex, it seems like a feat of engineering on all sides involved.
Not according to the Turkish government.
https://www.theguardian.com/world/2022/jun/03/turkey-changes...
Alphabets and certainly diacritics are used differently in different languages, so insisting on a certain way of writing can only lead to inconsistent pronunciation.
How is that related to what we're talking about?
> does not deserve that moniker
That's pretty extreme. One story you didn't like, and that's it? I don't think anything, certainly not press releases, will meet your standard.
[1] https://www.scientificamerican.com/article/how-ukraine-unplu...
WP articles about this: https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta... https://en.wikipedia.org/wiki/European_super_grid
The European grid has nothing to do with the EU. The grid includes non-EU countries like Switzerland and Norway. The UK did not leave the grid after Brexit; its interconnections with Ireland and the continent still exist.
The US and Canada's grids are interconnected without the two nations being integrated as closely as the EU member states are.
Texas has made a conscious decision since 1935 when FDR signed the Federal Power Act to stay away because they didn't want the feds to mess with their grid. The feds have no power here because the Texas grid does not cross state lines. When West Texas Utilities did connect through state lines in 1976 (called the Midnight Connection) both HL&P and Texas Electric Service Company immediately disconnected from them to avoid falling under federal regulation. It was not the feds. https://www.bakerinstitute.org/research/connecting-past-and-...
And sure, other countries can integrate too, and in fact do. Nobody said only EU members are allowed to do it. It is however the largest grid on earth, and therefore a technical and political feat.
Not perfect, and certainly not invulnerable to bad actors, but still a beautiful accomplishment of will and politics.
Plenty of strife and conflict can be and are found where most western eyes generally don't look.
By that measure, you'd consider the peace ended in 1956 when Russia -- then called the Soviet Union -- re-invaded Hungary after very briefly withdrawing. (As an aside, when the National Bank of Ukraine last year opened two donation accounts, I sent 1956 EUR to both. I am not subtle with my messaging.)
On 15 November 2022, a missile struck the territory of Poland at the village of Przewodów near the border with Ukraine, killing two people.[1][2][3] ... It was the first incident of a missile (vis-a-vis prior UAV incursions) fired from Ukrainian army[6] landing and exploding within NATO territory ... Initially Ukraine accused Russia of striking Poland,[9] while United States claimed that the missile was likely to have been an air defence missile fired by Ukrainian forces at an incoming Russian missile.[10][11][12] This was later confirmed in September 2023 by the Polish Prosecutor's Office, which stated that the explosion was caused by an out of control air-defence missile S-300.[6][13]
> Neither Russia nor Ukraine are members of the EU.
Europe != EU
Also, explosives from the Russian invasion in Ukraine have hit the territories of two EU countries: Poland and Romania.
It kind of feels similar to how monarchs tried to form lasting peace further back: inter-marry so that everyone is someone’s cousin they grew up with. Of course that didn’t exactly work perfectly.
Did not work terribly well for the former Soviet republics :(
On one hand, I read experts say that. On the other, I read experts point out that it failed to prevent WWI.
I wonder what the consensus is, if there is one, and what the evidence is.
Indeed it would be interesting to see experts attempt to enumerate situations that were avoided through this approach. Though I’m not sure if that’s even possible given it requires a form of alternate reality synthesis which is all but pure bias.
A statistical approach may find there’s still too little data?
Yes, absolutely. Also, it generally makes us wealthier.
I think it's a totally naive view. Even if we limit ourselves to only thinking about rational actors, we must always ask about economic costs for whom. Nation states do not operate as a unit as a rational economic actor -- we must look at the competing actors within. One group could somewhat win, and another substantially lose, and that may net out to a negative -- it happens regularly. Many are clamoring for it right now -- a new Cold War against China.
The principle that member nations have alignment and act (mostly) in unison.
* https://new.abb.com/news/detail/19701/abb-wins-600-mw-hvdc-o...
Another thing that made a really strong impression was visiting a power dam and realizing that it was almost dead quiet while an enormous amount of power was being generated. Just a slight hum and a vibration in the floor, that was all.
75 deaths. RIP.
Clicking the prominent "refuse all" button works
It does seem a little weird though.
Solar inverters can produce/absorb reactive power easily - but while that can frequently be configured from the control panel of individual units, rarely is that ability exposed to grid operators.
Inverters at DC undersea links can do the same. As can some kinds of wind turbine.
All three can also absorb harmonic power and emit it as fundamental frequency power.
Battery energy storage systems can also do all of that, plus also provide 'simulated spinning reserve', and also provide brief huge increases in energy output to deal with various collapse conditions.
Wind can also do this (with caveats).
However, despite lots of 'green' energy sources having the necessary abilities, it frequently is lacking software support, particularly in the 'control plane'. Part of that is because there is no legal mandate to have these abilities, and there is (in most markets) no payment for providing this service. Therefore operators don't bother to enable these features.
The only thing that can help in that case is batteries.
98% of the power plants I’ve been to run the voltage regulator in voltage control mode with 5% droop. Solar and wind farms can do that too, and I am sure it is required by the system operators to allow them to connect.
If grid operators want more or less reactive power they call us and tell us to change our voltage setpoint on our plants. Can’t they do the same with solar and wind? The grid operator does not need real time control of the setpoint since the control loop responds in real time.
Solar and wind systems today typically do not have a voltage setpoint or control loop. That's because there is no big gas/steam valve to adjust the amount of power generated. The operator wants to inject all the power from the sun/wind into the grid, whatever the voltage.
An X% droop would be X% of the total generated energy wasted in the name of stability. Thats a lot of money, and they won't waste it unless required to.
Instead, power deficits in the 10's of millisecond range can be dealt with by inverters (which typically have storage capacitors for ~20ms worth of output). This covers large fault currents, and sudden inflows as bits of grid are reconnected.
Unfortunately, most of today's inverters, which have the capability to do that, will not, due to having code which will only operate the 'happy case'.
> Solar and wind systems today typically do not have a voltage setpoint or control loop. That's because there is no big gas/steam valve to adjust the amount of power generated. The operator wants to inject all the power from the sun/wind into the grid, whatever the voltage.
reactive power being easily controlled is the same as a voltage control loop with droop when connected to a larger system.
Control of the traditional prime mover by way of devices like steam throttle valve controls real power (MW) and not voltage or reactive power (MVAR).
I am curious how an inverter operating away from unity power factor fails to deliver roughly the identical amount of energy as at unity. Can you provide a link that explains it? Traditional generators pump out the same MW barring losses due to increased current no matter the power factor. MW in mechanical * efficiency = MW out electrical. And of course there is a limit to how out of phase the voltage and current waveforms can be, usually +/- 0.9 pf.
A 60Hz cycle is 16.7 ms, A 13 kV breaker takes 80ms to open, to detect a fault (except for differential element) let alone clear it takes a lot longer than 20ms.
While that's true, sometimes it's easier to have a single-purpose infrastructure, so that you don't have conflicting requirements.
For example, if a wind farm needs to feather its turbines due to excessive wind (which could damage the turbines), that could conflict with a simultaneous objective for frequency regulation.
Because the general consensus seems to be that large things like pumped hydro are good for centralized energy storage, while batteries are the choice for decentralized energy storage -- whether in your utility closet or in your EV.
Why should anyone choose a flywheel over a battery?
Advantages over chemical batteries:
>85% round trip efficiency (DC)
>No daily cycling limitations
>No degradation over time
>Full power over full State-of-Charge range
>No HVAC required
>Operates in hot and cold environments (-20C to 50C)
>Fast response time (<1 second)
>Sustainable and recyclable all-steel design
>Safe & reliable–no fire hazard
>Lower O&M cost
>30-year design life
None of these are exactly a problem, they just cost money to implement properly.
I would say this copy + pasted list is not great.
No HVAC required - ok but you do need to suck down a huge vacuum, which is a lot more difficult than traditional HVAC
Hot and cold - see above point
All steel - not sure about that, maybe for lower speed applications, which reduces the amount of energy stored
Safe & reliable - hard to say that a huge mass spinning >100k rpm is "safe". By itself there is no fire hazard sure. but what if your magnetic bearings fail and it hops off and starts trying to escape it's (vacuum) enclosure. Then you have tons of sparks and pressure differences and other non-fun things.
O&M - [citation required]
30 year life - surely with all the plusses listed, it should be longer than 30 year life?
1. Pumped hydro is currently best for long term-storage. The lack of other cost-competitive long-term storage options is currently one of the biggest issues with renewables and an active area of investigation.
2. Batteries are good for daily smoothing (i.e. when the sun goes down), but they have limited charge/discharge cycles, they lose charge over time, and they don't, as of yet, have storage capacities needed for long term storage.
3. As the article points out, flywheels are good at instantly changing output based on changes in the grid, so they're good for frequency regulation and onboarding/offboarding new energy sources. Their biggest downside is their limited capacity compared to other tech.
https://amberkinetics.com/installation/the-reliable-energy-s...
Placeholder site: vortical.io
Though 97% of that energy isn’t available to the grid as the name synchronous condenser implies.
You'd use something like this while bringing online alternative sources of energy, which takes time. Of course a grid battery probably wouldn't need this as it would be similarly quick to come online. Which raises the question why they are going for synchronous condensers instead of grid battery. One doesn't exclude the other of course.
This is evidently something similar but for AC. It stabilizes the AC voltage / phase because its momentum pushes back against whatever tries to disturb it.
You mean, "Though 97% of that energy isn’t available to the grid COMMA as the name synchronous condenser implies."
You don't mean (as I read it before), "Though 97% of that energy isn’t available to the grid, and the name synchronous condenser implies the energy is available."
Well, it's only available to use when the power fails or something like that.
When you first power up, it requires a finite amount of time for the storage/filter capacitor(s) to charge up to their full design voltage before your circuit really works as intended.
Later when you disconnect incoming power, the stored energy from the capacitors does continue to supply DC power to your circuit for a finite amount of time afterward, at declining voltage as the capacitors are drained.
>This is evidently something similar but for AC. It stabilizes the AC voltage / phase because its momentum pushes back against whatever tries to disturb it.
Yes, I think this is it.
Seems to me these massive AC stabilizers would help maintain frequency and voltage during unavoidable events where the grid dropped below nominal, by more gracefully dropping when necessary as the grid sucks momentum from the stabilizer down to its own level at the time.
And if power completely failed it should end up in a more graceful "wind-down" as all momentum for all stabilizers require a finite amount of time to come to a complete halt, letting whatever limited amount of stored energy they contain be delivered to the grid until there is no more.
Today the research focuses on "Grid forming inverters". Taking the same principle as powering a home in island mode and stretching it to the entire grid allowing non-synchronous generators to provide the system strength.
Over time they are a net power drain for the grid, but as parent says offer synthetic grid stability independent of power sources.
(Sorry for asking such a poorly stated question that I really haven't thought through — I know very little about electricity and you seem to understand quite a lot about this subject.)
Someone have a link to 101 power transmission? I find this fascinating.
The phase difference is not really about distance it's more about energy flows, where it's lagging there more power is used and where it is leading more power is generated. The flow will be from early phase to later.
But how would current and voltage be stabilized in that case? Just huge capacitors? Chemical batteries?
Grid itself can't store energy, the generation and consumption needs to be in balance.
If transmission balance goes out of whack more electrons want to flow to specific places and will always try to take the path of least resistance.
Those paths (as in transmission lines) have their current capacity measured in Amps and when it gets too much their protective equipment in the for of active or passive circuit breakers will take them offline (trip) therefore moving the current down next best paths and further increasing the likelihood of trips.
Voltage is regulated by changing the windings of transformers in AC-AC systems or by transistors/thyristors in DC coupled networks.
Frequency has usually been regulated by spinning mass, a steam powered generator has a pretty large inertia and when it slows down there is a governor or other control mechanism to add energy to the generator via opening steam valves and maybe adding fuel. If speed goes too high it is also reduced.
For large load changes there are further compensatory mechanisms. Like heavy industrial plants measure grid frequency and when it falls below lets say 49.9Hz then they will immediately trip themselves offline and shed a huge amount of load from the grid. They get paid for this.
So while there may be huge variance in on both sides (a sunny day, a wind gust versus switching on the AC a train leaving the station) the only way to adjust is open a valve add steam, fuel? Will that scale to when, say, 80% of electricity sources are weather dependent? Or is that the pumped hydro / big batteries / future technology stuff?
[Sorry for going off topic, here]
But weather can span large areas and the solutions can be roughly categorized as:
- some form of energy storage: batteries, hydro (can be pumped), flywheels, etc
- dispatchable power - gas fired turbines, coal or wood fired thermal plants, nuclear, etc
- demand side response - time of use pricing (like nordpool spot market prices) or getting paid to switch off your AC during peak hours, etc.
Traditionally we have had a grid management mindset of "generation adapts to load", everyone uses as much and when they need and grid/generation adapts to it.
With only renewables the mental model of "load follows generation" could make sense, people (or rather peoples devices) get a signal when it is most beneficial to consume and when not to.
I think the reality will be some combination of all of the above. Mostly renewables but also diverse set of renewables that are somewhat anti-correlated, like wind+solar plus distributed. The shortfalls could be filled with natural gas fired power plants. Some nuclear when/if built/available combined with smart cars and devices. V2G will get there eventually as well and then the car battery will have much more energy available than a typical home uses in a day.
Cruachan to the rescue.
https://en.wikipedia.org/wiki/Cruachan_Power_Station
Zero to full production in two minutes, 30 seconds in an extreme case if required. It's the Power Infrastructure equivalent of a supercar.
That's why the grid will selectively island parts that are too far out of phase. Normally this should not happen though.
Sigh…
The article mentions the critical parameters which historically have been sourced from big heavy generators like hydro, coal, nuclear or CCGT plants:
- Frequency regulation: When grid power crashes or surges, the device immediately releases or absorbs energy to minimize fluctuation in the AC frequency;
- Short circuit power: When the grid experiences a short circuit, the crashing voltage releases a tripling or more of current from rotating machines which signals breakers on the grid to activate and quickly isolate the fault;
- Voltage support: Producing current and voltage that are out of phase generates so-called reactive power that pushes the local grid’s voltage up or down to stabilize system voltage and/or increase the flow of real power.
This is about Inertia and frequency control. Not about bulk energy storage.
[1] https://spectrum.ieee.org/media-library/a-map-of-the-baltic-...
[2] https://www.army-technology.com/features/featurethe-10-most-...
[3] https://en.wikipedia.org/wiki/Upshot-Knothole_Grable#/media/...
Lithuania, Estonia and Latvia would be better off eliminating those dependencies entirely by focusing on expanding their domestic renewable energy production infrastructure.
Perhaps, but the time scale for that is much longer than this, and they're very eager to switch ASAP.
There are also a lot of renewable energy projects in progress to replace the shale oil systems, but again - capacity isn't the issue.