@transparent 

Red Eléctrica will require data with greater granularity than 1-second internals.
Inverter technology acts very much faster than do rotating turbines.

My bad.... Milliseconds, obviously -  I'm working in too many languages, too late at night. And to be clear, that information came from Beatriz Corredor the CEO of Red Eléctrica. 

Super fascinating to hear how they ran the black start with assistance from France and Morocco and by firing up islands before relinking each piece back to the whole when all was operating properly. Obviously, I'm vastly simplifying here... 

The committee will provide an interim report in 10 days but the full deal will be months away. It's a seriously high level team which includes the ministry of defence.  

Thanks for the 2019 details. Very interesting. 

Posted by: @jeff

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Doubling of annual allowance for distribution network spending. Sounds a lot to me.

Yes, it's far too much money.

DESNZ will no doubt wish us to reflect on the positive aspects of such expenditure...
... but it's got to come out of our pockets over several decades, as we pay back the commercial companies who are being permitted to saddle us with this debt.

What we really need is an Industry Regular who is charged with the responsibility to act in the best interests of consumers....

“What we really need is an Industry Regular who is charged with the responsibility to act in the best interests of consumers....”

what an excellent idea! Perhaps we should call them Ofgen?

🤔

Back to Iberia: some more information and explanations of terms here.

https://ctse.aei.org/the-iberian-blackout/

The “shake” in the Aragon-Catalonia corridor caused the French interconnection (and many other generators presumably) to drop out and without the French feed the Spanish grid could not be stabilised. Next question what caused the frequency “shake” which must have been generating/load changes.

Historically, it's been low generation from fossil fuels which has resulted in supply disruption by a sheikh.

Posted by: @judith

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Back to Iberia: some more information and explanations of terms here.

https://ctse.aei.org/the-iberian-blackout/

The “shake” in the Aragon-Catalonia corridor caused the French interconnection (and many other generators presumably) to drop out and without the French feed the Spanish grid could not be stabilised. Next question what caused the frequency “shake” which must have been generating/load changes.

Oh my……. American Enterprise Institute another fossil fuel-funded lobby .... And sure enough their ‘solution’ (last sentence) is nuclear and gas ‘for stability’.  🤦🏻‍♀️

The only information that has been released by Red Eléctrica is what was in the early media conference call on the first day. This is where the details were published about the two shutdowns in the south west of Spain etc., 

It was then published widely but as I said, the anti-decarbonisation lobby picked it up and did their usual trick of ignoring bits or adding imaginary scenarios without spelling out which bits came from their imaginations. A pinch of fact and two spoonfuls of spin. That’s what they do.  

And that’s what Javier Blas from Bloomberg did. He threw his own views about inertia into his comments. But then the anti-renewables lobby picked it up and blew it sky high…

If you unpack that article it is a hodgepodge of other people’s work, including the FT (who was on the conference call), and bits that have been circulating on Twitter/X by people adding their 2 cents but no ‘inside knowledge’. 

And some of it is just plain wrong. For example, ‘Portugal relies on Spain blah blah blah’. That’s a serious case of: ‘show me you don’t know how transnational grids work without saying you don’t know how.. etc’. 🤦🏻‍♀️

The ‘inertia’ argument was jumped on within minutes of the blackout by everyone and their fossil fuel auntie then spun (see Daily Telegraph & Ms Watt Logic on GB News etc.) The truth is - we don’t know. Certainly no one in that article knows. It's utter spin dressed up with a pretty (and pointless) chart. 

Beatríz Corredor, CEO of RE has since made a couple of passing comments to say it wasn’t ‘caused by renewables’ but what that means is anyone’s guess. 

John Kemp is a newly minted oil and gas analyst, so not exactly invested in renewables, the same can be said of the other contributors. All this stuff was floating around within hours of the shutdown. 

@lucia    “I was given some information by Spanish engineers last night that flies in the face of some of the 'inertia' theories. But as I'm way too busy today to start phoning Red Eléctrica to check it out - I'll leave it at that.”

A contact, a Spanish engineer, reckons there was 8GW of inertia on the grid at the time of the incident. Plus 1.5 GW spinning primary reserve, 35% of total generation. I didn’t put those details in my post, I just said he challenged the inertia argument. I have no way of checking this at the moment, although he’s usually reliable and it’s his job. 

He wasn’t the only one… Plenty of more neutral observers point to the inertia provided by nuclear, hydro and solar thermal on the grid at the time of the blackout, plus Red Eléctrica has built in “synchronous condensers” to help boost inertia and grid stability. They’ve also been building out BESS battery plants on a big scale. 

The chart in that article is the EUs open data live data mapping. The same kind of thing as the two operators - Spain & Portugal - have in their very slick apps or the Nat Grid app for the UK - I have an iPad full of them. A chart always depends on interpretation and context and it’s amazing how they dazzle people and carry visual weight. But it proves nothing. In this case. 🤓 

They have zero idea whether there was an inertia problem… or not. There may have been, there may not have been or, more likely, a complex set of issues. With minor exceptions, anyone who says otherwise at this point, is talking out of their proverbial. And the Cataluña bit is an invention. 

@lucia “At 12.33 the there's 2 drops in frequency, associated with the two losses, and then a rapid rise and fall in frequency outside Spain as the FR-SP interconnectors began to interrupt and the full event unfolds from 12h33 CEST. The main events lasted less than twenty seconds.

It was the France/Spain interconnector tripping that triggered the cascade. 

What is absolutely extraordinary (utterly thrilling for my project 😁) is today I was told that frequency disturbances were observed as far away as eastern Europe.”

I shared the details about the France/Spain interconnector tripping because my source for this is a former Director of Ops for National Grid and has actual physical equipment monitoring various parts of the EU grid (including UK) measuring frequencies etc., thus he is working with his own company’s equipment and data and not interpreting someone else’s. 

I’m old school, I like to cross check and be sure before I put my name to things.  Until Red Eléctrica publishes their report it’s all speculation. Even the meeting with all the European grid directors didn’t take place until late in that day. Thus no one had a privileged view. 

Everyone (apart from the people whose details I’ve shared) that day were all WITHOUT EXCEPTION recycling variations on the conference call for the press which I was on. It’s extraordinary. 

For me, as I said, the Iberian grid is part of 'my thing' right now so it was just pure coincidence that I am monitoring it daily, and have a bit of background knowledge and good contacts. Plus there was a major energy security conference in London last week. But I have no ‘answers’. 

I’m used to this when I worked in breaking news for BBC or when I was covering foreign policy - an ‘event’ would happen and out popped the instant experts, those with various agendas, and even those who seem to just plain get a thrill - I guess that’s the nature of social media and ‘personal branding’.  It was not such a problem previously. 

But grid shutdowns? Holy smoke even my kids think this is a geek too far…. Eye rolls and yawns all round. So I really didn’t expect it (except from the fossil lobby who are apparently all now inertia experts).  🤦🏻‍♀️

Anyway, forgive the essay, (and me quoting myself) I just want to counsel everyone to PLEASE read cautiously and carefully when renewables stories are in the media. 

Let me add two other points to what @lucia has just posted.

1: We do not yet know if Spain and Portugal have their own equivalent of Load Shedding, which I explained here earlier.
That was the main factor which allowed NG ESO to reverse the falling frequency in GB's outage of 2019.

This Lower Frequency Demand Disconnection (LFDD) mechanism operates in staged blocks of 5%, 7½% and 10% of total national demand.

2: There are a few technical differences between the domestic level of inverters which export to the grid,
and those deployed from commercial sites (which are 3-phase of course).

The EREC G98/G99 regulations stipulate that a grid-tied device must remove itself from supplying the grid within milliseconds if it detects:

• under-voltage - a predefined point below 216.2v and above 186v (on a 1ph supply)
• over-voltage - a predefined point above 253v and below 162v
• frequency change of 1% above or below 50Hz

Let's just look at that in practice.
Here's an over-voltage just after 3pm yesterday which was insufficient to cause a domestic inverter to de-couple from the grid:

Times on the x-axis are UTC (not BST).

If inverters in the vicinity of that over-voltage had isolated their grid connection, then they would have waited for a randomised period of time
after the fault was cleared before re-establishing that grid connection.
That is typically around a minute.

Commercial inverter equipment which can export under G99 will measure parameters to greater detail before removing itself from the grid:

• RoCoF: Rate of Change of Frequency which exceeds 0.125Hz/S
• Vector Shift: a variation of more than 6% from the 120° difference between phases

Unlike domestic inverters, some of the larger 3-ph inverters can respond dynamically to RoCoF, and therefore assist in pulling it back towards 50Hz.

But, even if the inverters do disconnect themselves, they can attempt to reconnected to the grid in much shorter time-frames.
These are typically 100mS to 5 seconds.

If you want to read a huge amount of speculation, fabrication and prejudice dressed up as fact you can read Linked-in. Sadly it’s getting more FB like. 
That’s not a recommendation btw.

A small FACTUAL update (which echoes what 'my' expert said about frequency oscillations elsewhere in Europe -see my post above).

Note there are no conclusions about causes and the Spanish report is not due yet. Source for the below is EU system operators:

During the half hour preceding the incident, two periods of oscillations (power and frequency swings) were observed in the Continental European synchronous area, between 12:03 and 12:07 CET and between 12:19 and 12:21 CET respectively. The TSOs of Spain (Red Electrica) and France (RTE) took actions to mitigate these oscillations. At the moment of the incident, there were no oscillations and the power system variables were within normal operation range.

Before the incident, the international exchange programs of Spain were 1,000 MW to France, 2,000 MW to Portugal and 800 MW to Morocco, all in the exporting direction.

 Data so far, have yielded the following sequence of events during the incident:

1. Starting at 12:32:57 CET and within 20 seconds afterwards, presumably a series of different generation trips were registered in the south of Spain, accounting to an initially estimated total of 2200 MW. No generation trips were observed in Portugal and France. As a result of these events the frequency decreased and a voltage increase is observed in Spain and Portugal.   
2. Between12:33:18 and 12:33:21 CET, the frequency of the Iberian Peninsula power system continued decreasing and reached 48,0 Hz. The automatic load shedding defence plans of Spain and Portugal were activated.
3. At 12:33:21 CET, the AC overhead lines between France and Spain were disconnected by protection devices against loss of synchronism.
4. At 12:33:24 CET, the Iberian electricity system collapsed completely and the HVDC lines between France and Spain stopped transmitting power.

That's it folks. Take note again this offers NO conclusions about causes and speculation is unhelpful. 

Posted by: @lucia

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Between12:33:18 and 12:33:21 CET, the frequency of the Iberian Peninsula power system continued decreasing and reached 48,0 Hz. The automatic load shedding defence plans of Spain and Portugal were activated.

I think that's too low.

I believe the British DNO's automatic Load Shedding commences at 49Hz.
In August 2019, it was already occurring by the time the frequency dropped to 48.8Hz.

Below 49Hz there will be stand-by generation sources which can no longer be brought on-stream.

Unless the generation frequency matches the current grid frequency, the fuses blow (or contactors open) because there is too much current flowing back into the generation-set.
Your one (relatively small) generator is trying to drag all the rest of the grid back to 50Hz on its own!

Posted by: @lucia

↑

A small FACTUAL update (which echoes what 'my' expert said about frequency oscillations elsewhere in Europe -see my post above).

Note there are no conclusions about causes and the Spanish report is not due yet. Source for the below is EU system operators:

During the half hour preceding the incident, two periods of oscillations (power and frequency swings) were observed in the Continental European synchronous area, between 12:03 and 12:07 CET and between 12:19 and 12:21 CET respectively. The TSOs of Spain (Red Electrica) and France (RTE) took actions to mitigate these oscillations. At the moment of the incident, there were no oscillations and the power system variables were within normal operation range.

Before the incident, the international exchange programs of Spain were 1,000 MW to France, 2,000 MW to Portugal and 800 MW to Morocco, all in the exporting direction.

 Data so far, have yielded the following sequence of events during the incident:

1. Starting at 12:32:57 CET and within 20 seconds afterwards, presumably a series of different generation trips were registered in the south of Spain, accounting to an initially estimated total of 2200 MW. No generation trips were observed in Portugal and France. As a result of these events the frequency decreased and a voltage increase is observed in Spain and Portugal.   
2. Between12:33:18 and 12:33:21 CET, the frequency of the Iberian Peninsula power system continued decreasing and reached 48,0 Hz. The automatic load shedding defence plans of Spain and Portugal were activated.
3. At 12:33:21 CET, the AC overhead lines between France and Spain were disconnected by protection devices against loss of synchronism.
4. At 12:33:24 CET, the Iberian electricity system collapsed completely and the HVDC lines between France and Spain stopped transmitting power.

That's it folks. Take note again this offers NO conclusions about causes and speculation is unhelpful. 

The update above was posted here a few days ago along with other information for anyone interested 

https://www.entsoe.eu/news/2025/05/09/entso-e-expert-panel-initiates-the-investigation-into-the-causes-of-iberian-blackout/#:~:text=As%20a%20result%20of%20these,Spain%20and%20Portugal%20were%20activated.

@transparent 

1: We do not yet know if Spain and Portugal have their own equivalent of Load Shedding, which I explained here earlier.

We know Spain use load shedding and have used in anger. 

https://www.entsoe.eu/news/2021/08/20/outage-of-french-spanish-interconnection-on-24-july-2021-update/#:~:text=The%20low%20frequency%20load%20shedding%20scheme%20in,first%20and%20second%20stages%20of%20the%20scheme;&text=The%20countermeasures%20quickly%20stabilized%20the%20frequency%20in,just%2037%20minutes%20after%20the%20initial%20event.