Power cut in Spain and Portugal

[Snuggler]

Yes, 470 kV on the 400 kV lines, that´s tripped the relays in the end. That's been known for a while.
But what tripped the three powerplants?

[Siwastaja]

And the official report (in Spanish):
Se presenta el informe del Comité de análisis de la crisis eléctrica del 28 de abril: https://www.miteco.gob.es/es/prensa/ultimas-noticias/2025/junio/se-presenta-el-informe-del-comite-de-analisis-de-la-crisis-elect.html

Nice to have the first official report, I'm sure entso-e's will follow later. Interesting points:
* Cause solely overvoltage, nothing to do with frequency oscillations or "too little inertia"
* Large plants misbehaving and shedding production well before correct overvoltage limits
and my favorite part:
* There is voltage control reserve market in Spain, and plants were paid to be in voltage control reserve, but once it should have activated, the controls did not work and did random things, including some with the opposite response.

This is specifically interesting as we are working on participating in frequency containment reserve markets in the Nordic synchronous area, and some of our competitors who are failing their acceptance tests are behind the scenes bitterly complaining about the regulators being stupid and ruining their business. But these rules and strict testing exist for a good reason, especially with reserves that seldom activate there is temptation to just get the moneyz with non-functioning system.

In fact, seeing improvement of compliance verification and oversight as the first main recommendation of the committee underlines the importance of pre-compliance testing for power system providers.

And maybe most interestingly, but not surprisingly at all: no mention of "excess solar", or household distributed rooftop PV playing any part in the indicent. Apparently, multi-megawatt plants directly feeding 400kV are more susceptible to having "wrong settings", than those feared Chinese inverters.

nctnico must be disappointed 

[dietert1]

Yes, Spain is known for corruption. My wife happened to watch how hundreds of thousands of euros were earned  by cleaning the floors of new empty car factory halls. The factory could be built only after some local enterprise got those cleaning contracts.

Regards, Dieter

[johansen]

Block transformers step up to feed more reactive power into the grid. The energy in the grid is detected by the frequency, not the voltage. This is why the voltage is increased and the frequency is decreased.


This is from a prior reply.

I disagree with it. What i suspect happened was the generators that tripped were running at 90% pf as is allegedly typical.

The load being say 50% insensitive to voltage means that as the generators trip offline, which are a reactive load, the power flow into the south of spain increases, and the voltage rises due to the missing 200 to 400 mega volt amps of lagging power factor consumed by the tripped generation.


Ultimately the fundamental problem we will have going forwards is that more and more to the tune of 50% or more of the load, does not care about the voltage or the frequency..

Its only the remaining synchronous directly connected motors, larger than 100 hp induction motors, and resistive heating (quickly disappearing) that is affected by voltage or frequency.


At some point, who cares what the voltage or the frequency is?

[PartialDischarge]

The official report is done but not publicly published, the public version is 80% redacted, that goes to show the kind of transparency the gov shows.
In any case the gov and the owner of the grid are in the same bed, with political interests to smear nuclear energy, so I wouldn’t believe much in that report

[Snuggler]

[Marco]

* Cause solely overvoltage, nothing to do with frequency oscillations or "too little inertia"

It's completely impossible to get overvoltage at the large generators and switch gear in Spain on a sunny day. When any section on the grid will drop half its input power at over +10% voltage in milliseconds it just can't happen.

REE has its own view of what happened :

Later, REE said it observed a “significant” disturbance on a power line in Badajoz and reduced the electricity exchange with Portugal. At 12:16 p.m., the oscillation recurred, it said. It originated at a “photovoltaic plant that we will call A in the province of Badajoz,” which is “connected to the transmission grid.” Sánchez said the oscillation “unequivocally” resulted from malfunctioning internal controls at the plant, an issue “that must be clarified by the owner.”

The anomalous fluctuations led to the disconnection of 700 MW of generation, mainly from small facilities outside REE's visibility, including self-consumption plants.

Subsequently, export flows “reduced,” voltages kept rising, and a substation in Granada experienced a generation trip. Disconnections continued, including another 582 MW in Badajoz. When the transmission grid had lost over 2,000 MW and “a considerable volume” on distribution networks, the system could no longer maintain voltage levels.

Sánchez said that until that point “we cannot speak of overvoltages,” noting that voltage levels remained within regulatory limits. She also stated that some generators failed to comply with voltage control obligations. “They must provide this service,” she said. According to REE simulations, the blackout could have been avoided if generators had delivered the required voltage control, since “sufficient” capacity was available. “It's a different matter” whether the companies obligated to provide the service actually did so, she added.

So according to the REE General Director of Operations, the disconnects which brought down the grid occurred at a time when "we cannot speak of overvoltages". So it was a phase/frequency problem.

If inverters were more grid forming in their phase/frequency control instead of just having static volt/var curves, no inertia would be needed to fix situations like these. As it stands though, you need inertia to make the grid more robust to this kind of disruption (grid forming statcoms can provide inertia, doesn't need to be spinning metal).

[Siwastaja]

So it was a phase/frequency problem.

What is a "phase problem"?

[tv84]

https://www.eldiario.es/economia/red-electrica-situa-inicio-apagon-mal-funcionamiento-planta-fotovoltaica-badajoz_1_12394575.html

Red Eléctrica attributes the start of the blackout to a "malfunction" at a photovoltaic plant in Badajoz.

• It is a "perfectly identified" plant that is not revealed for "confidentiality" reasons; the system operator presents its own report on the blackout, anonymized like the government's report at the request of the companies.
• The government report on the blackout hides, at the request of the power companies, which facilities failed.

Antonio M. Vélez
June 18, 2025 , 12:06 p.m.
Updated on 06/18/2025 12:59 PM

Red Eléctrica (REE) on Wednesday attributed the start of the historic blackout of April 28th to the "malfunction" of a photovoltaic plant in Badajoz, which the company, in which the State is the largest shareholder with 20%, has "perfectly identified" but is not disclosing due to "confidentiality" issues. This solar plant was the cause of a "forced frequency oscillation" that the government report presented on Tuesday considered anomalous.

In a lengthy press conference at the Tres Cantos (Madrid) headquarters of Redeia, the company's parent company, to present its report on the blackout, the company's president, former Socialist minister Beatriz Corredor, denied the company's responsibility for the outage. This is something that, she said, will have to be determined "where appropriate" by the courts or the National Commission on Markets and Competition (CNMC).

Corredor, who has ruled out resigning, although he noted that his position depends on the decisions of Redeia's board of directors and its shareholders, wondered whether the presidents of the electricity companies would resign if it were determined that any of these companies were responsible for the blackout.

Redeia CEO Roberto García has asserted that REE "at no time" violated regulations; that the company "has acted diligently" and that he is confident that it will not have to assume "any type of compensation."

REE's General Director of Operations, Concha Sánchez, has placed the start of the incident at "12 noon" on April 28. Half an hour before the blackout, the system's status was "absolutely normal." "We had no indication of what was going to happen next."

But at 12:03 p.m., "the system began to suffer" a "forced frequency oscillation" that caused "a drop in the voltage level" and a "very significant" fluctuation that lasted for almost five minutes and required "immediate" action because it was a "dangerous" situation: the way the interconnection with France operates must be changed, ceasing to operate on alternating current and switching to a fixed setpoint, "something that was done in agreement with RTE," its French counterpart.

A "significant" disturbance was then observed on a power line in Badajoz, and the decision was made to reduce transmission with Portugal. However, the oscillation "recurred" at 12:16 p.m. "We continued disconnecting reactors to improve the voltage level in the system."

It comes from a "photovoltaic plant we'll call A in the province of Badajoz," which is "connected to the transmission grid." According to Sánchez, this fluctuation is "unequivocally" due "to a malfunction of the plant's internal controls." But this issue "logically must be clarified by the owner."

Following these anomalous fluctuations, an "anomalous growth" in demand is observed, which "is actually a disconnection of generation." 700 megawatts (MW) of small facilities over which REE has no visibility, including self-consumption plants, are beginning to be disconnected.

The export flow then "reduced," voltages continued to rise, and a generation substation in Granada tripped. Disconnections began to occur, including another 582 MW substation in Badajoz. By the time more than 2,000 MW of transmission grid power and "a considerable amount" of power in distribution networks had been disconnected, "it was no longer possible for the system to maintain its voltage levels." But until that point, "we cannot speak of overvoltages" because, he asserted, they were within the values established by regulations.
Another very "relevant" aspect is the "insufficient resources" to control the voltage, because there was a lack of "compliance" with the voltage control obligations of the generators that are supposed to provide this service. According to REE simulations, "we wouldn't have had a blackout." "The incident would have been avoided," Corredor asserted.

According to Sánchez, "having a more integrated group in the system wouldn't have changed things," referring to the government report highlighting that reserve power was at its lowest level in 2025, and that the day before, a combined cycle plant was declared unavailable, and REE didn't replace it. The company maintains that "given the circumstances" and "the best forecast we had," it was considered that there was "sufficient" voltage control capacity. "A different matter" is whether the companies that were supposed to provide this control service actually did so.

Corredor expressed confidence that the voltage monitoring service, which the National Commission on Markets and Competition (CNMC) has been considering approving for five years and which REE proposed in 2020, will be implemented "shortly."

The government report urges the immediate launch of this service, which would allow photovoltaic and wind power to participate in voltage control at a lower cost to the system. "It's not in our hands to approve the procedures," said Sánchez, who clarified that its effect would not be immediate: the first plants could provide this service "no earlier" than the first quarter of 2026.
This is a service that, according to the super-regulator itself, is obsolete and that REE proposed to the CNMC in 2021. The Competition Commission itself proposed changing it in 2019 and in 2022, acknowledging " ongoing voltage control problems " but addressing them with a pilot project.

REE has submitted the report on the blackout required of the system operator by current regulations (a 2019 operating procedure) when an incident of "particular significance" such as this occurs, with a maximum deadline of 60 days and measures to be taken to prevent a recurrence. This is a "complementary" document to the government's, explained Redeia president Beatriz Corredor.

REE has been singled out in the government report (which apportions blame among the system operator) for "poor planning," in the words of Vice President Sara Aagesen, regarding the reserve power in the market known as the technically restricted market. Sánchez asserted that with the available plants, "there were sufficient resources" to control the voltage.
The president of Redeia explained that it is "key" to keep in mind that the operator must carry out its functions with "transparency, objectivity, and economic efficiency": "at the lowest cost," as REE's general director of operations emphasized. The company "does not manage the distribution networks" or the private generation evacuation networks, or the control centers linked to the other operators, although "evidently" there is "coordination in the forecasting and operation" of the system.

The company has prepared its report using the information available "to the extent of the system operator's observability." The other operators, Corredor explained, have provided "partial information," sometimes lacking "the desirable quality," without "always" providing the data submitted, and with the companies "specifying its confidentiality." Therefore, like the government's report, the content will be published "anonymously" and was presented this Wednesday at an event "to which we are not obligated" and "in the interest of the public."
"It is not our responsibility to determine responsibilities," Corredor said. "That is the responsibility of the investigating authorities," the CNMC, ENTSO-E, and the National Court.

Regarding the government report presented this Tuesday, Corredor emphasized that REE authorized the release of "all data" affecting it, while the private sector did not: "It is clear that not all stakeholders in the sector have done the same." Since May 1, REE has sent 57 reports, some consisting of dozens of documents, to the committee investigating the blackout, in addition to the information from the so-called "black box" of the electrical system.

[Marco]

What is a "phase problem"?

Mostly oscillation.

With 50% contribution of PV to a grid you can have over-current trips, you can have out of bounds frequency trips ... but you simply can not have over-voltage trips. No matter what inductive currents are flowing, if 50% of input power drops out in milliseconds at nominal voltage +10%, voltage stops rising immediately. It shall not pass.

[Tation]

It comes from a "photovoltaic plant we'll call A in the province of Badajoz," which is "connected to the transmission grid." According to Sánchez, this fluctuation is "unequivocally" due "to a malfunction of the plant's internal controls." But this issue "logically must be clarified by the owner."

A Spanish newspaper claims such "A" photovoltaic plant to be a well known 500 MW one.

[tatel]

For all hose who deny how radiactive waste is being pumped in the ocean, a french expedition has found about a thousand barrels near Galicia. Just the first day.

But even more interesting is this documentary from Deutsche Welle made some years ago. I can only find it in spanish but of course you know how to get translated subtitles. It looks that, even today, nuclear waste is being dumped into the sea from La Hague in Normandy and Sellafield in the UK

[Halcyon]

tatel, let's keep the conversation on-topic. I have no idea whether your post is true or not, but it's not relevant to the conversation.

[Jeroen3]

They have added data:
https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/

[tv84]

From Vulnerability to Resilience: How Portugal’s Mobile Networks Handled the Iberian Peninsula Blackout

https://www.ookla.com/articles/portugal-resilience-2025

[hllns]

They have added data:
https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/

ENTSOE published a full factual report yesterday, same URL https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/

[Siwastaja]

They have added data:
https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/

ENTSOE published a full factual report yesterday, same URL https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/

Says that ~4 more months needed for any analysis & recommended actions, which will be a separate document 

[Jeroen3]

Oh, that is very detailed.

I like how they name it "factual report" to only blame implicitly.

[tatel]

This video -in spanish but you can of course have it subtitled in you language- is accurate?

Anyway the only really interesting part would be in the last five minutes.

The meat would be:

There were a couple of perturbations 0.6 and 0.2 Hz in all of Europe, that were stronger in the iberian peninsula due to some "whiplash effect". REE was unable to compensate because 22% of power plants, in charge of compensations, were not doing their contracted work,

These were thermal power plants, so I can only assume these were the big companies who didn't fulfilled their contracts. One of the thermal power plants even did the contrary of what they should do to compensate the perturbations, making it worse.

Which was my guess from the beginning: our oligarchs are to blame, and, since they are oligarchs, they can get away with it, and by the way, get an excuse to promote nuclear. Am I right?

[tggzzz]

Am I right?

Thanks for summarising the video.

Whether or not your political presumptions are correct, you sound like treez

[Siwastaja]

REE was unable to compensate because 22% of power plants, in charge of compensations, were not doing their contracted work,

It is interesting to see what Entsoe is going to say in their "analysis" report, because REE already made quite clear claims that contracted voltage reserve providers did not do their job, or did the opposite, yet I was unable to find anything supporting these statements in Entsoe's first part of the final report (the "fact" parts).

What seems clear is that voltage controls were lacking, but was it due to negligence (incorrect usage of existing resources), or just poor resourcing / poor power system design?

[radiolistener]

It worth considering that such large‑scale blackouts may function as a form of stress‑testing in preparation before high‑intensity war conflict scenarios. Their practical effect is to expose hidden vulnerabilities that would become critical if an adversary attempted to disable the power system through sustained drone and missile strikes. Based on some observations, large-scale stress tests of this kind are typically conducted approximately from 0.5 to 2 years in advance of actual events.


In the context of power outages, there is also interesting trends and news about some requirements for EU Member States which should be implemented by the end of 2026... I just wonder, what vulnerabilities would Spain face in the event of a sudden failure of electronic services such as electronic payment systems, digital ID, digital signatures services and other (due to power outage, destroying datacenters, etc)? How dependent is the population on these services today? How long would essential resources remain accessible, and could society adapt quickly enough to prevent a broader systemic disruption and collapse due to missing electricity, electronic payment systems and other electronic services? How long can you live normally when these services suddenly disappear or become unusable?

[tatel]

REE was unable to compensate because 22% of power plants, in charge of compensations, were not doing their contracted work,

It is interesting to see what Entsoe is going to say in their "analysis" report, because REE already made quite clear claims that contracted voltage reserve providers did not do their job, or did the opposite, yet I was unable to find anything supporting these statements in Entsoe's first part of the final report (the "fact" parts).

What seems clear is that voltage controls were lacking, but was it due to negligence (incorrect usage of existing resources), or just poor resourcing / poor power system design?

Of course, I don't really know. Apparently this guy looked at Entsoe report and found there some stuff about another report, ordered by an external enterprise, to look how many private enterprises did not fulfill technical rules, and found that 22% number. This statement can be seen at 25:42 mark.

I don't even know if that statement is just about the "compensators" or on the contary, any private enterprise involved in that's day mess, i.e, regular providers also, since, it looks,  a couple provider facilities got disconnected too early.

For little companies with PV facilities, I could buy that "negligence" thing. But, not for the big companies, who own the TPPs contracted for compensation. IIRC, one of these companies even refused to apport any documentation.

[johansen]

In the context of power outages, there is also interesting trends and news about some requirements for EU Member States which should be implemented by the end of 2026... I just wonder, what vulnerabilities would Spain face in the event of a sudden failure of electronic services such as electronic payment systems, digital ID, digital signatures services and other (due to power outage, destroying datacenters, etc)? How dependent is the population on these services today? How long would essential resources remain accessible, and could society adapt quickly enough to prevent a broader systemic disruption and collapse due to missing electricity, electronic payment systems and other electronic services? How long can you live normally when these services suddenly disappear or become unusable?

this isn't ww2 where every family had a month or two of flour in the basement.

3 meals.

[radiolistener]

this isn't ww2 where every family had a month or two of flour in the basement.

3 meals.

Based on my experience, I recommend maintaining a one-month supply of drinking water and at least a six-month reserve of food. Keep in mind that, in the event of a complete blackout, tap water will become unavailable. For this reason, consider installing a well with a mechanical pump, and be sure to locate the nearest natural spring and familiarize yourself with the routes to reach it — access to potable water is critical for survival. Do not assume that you will be able to rely on your smartphone or Google Maps.

While communities can often self-organize and may provide some essential goods (like bread, vegetables, canned goods) under modern conditions, you should not rely on this during the first 7–10 days of an emergency. During that initial period, you will essentially be on your own. Therefore, it is vital to have at least a one to two-week supply of water and food, without it, your situation could quickly become dire.

Some stores may continue operating even without electricity, but keep in mind that they will not accept bank cards or electronic payments - cash only, and you may need to wait in line for five to six hours just to enter. ATMs, even if power is restored intermittently, will be useless, as they will run out of cash quickly. Do not rely on them.

Also exercise caution, as criminal activity and looting typically increase in the immediate aftermath of a full blackout. Be prepared for the possibility that, even if you manage to obtain some food, you may be at risk of having it taken from you on your way home.