al report

Because if not, they would not have talked and the cause would not be known and corrective action not taken fast.

Ahh. It wasn't something the Spanish Government said then. My question being if they are in a plausible range of sizes to be a real solution, versus a stage-prop toy.

That WEG machine for Brazil certainly looks plausible, but one assumes that it's on the large end of the scale or it would not be featured.

Thanks,

Joe

Finding a culprit to sue will take decades (it is another investigation), and we want solutions now.

I prefer to have electricity than a culprit.

If their identities were not anonymized, they would not have talked at all. It would have taken years to have a working report.

I prefer to have this report now, so that it can be acted upon, and let the courts find the culprits to sue at their leisurely pace in a decade time.

Typical American: Sue! Sue! Sue!

Jeroen Belleman

Y'all come visit, and see.

Cheers

Phil Hobbs

Not right now, sorry. Too afraid to end up in a Salvadorian prison. Maybe when civilization returns.

Jeroen Belleman

Well, you’d know best if you’re likely to commit a Class A felony, but I wouldn’t have thought it.

;)

Cheers

Phil Hobbs

Summary: over voltage. We need a new EU regulation covering that. Renewables were not to be blamed.

Using DeepL automated translation.

When asked about the role of renewable energies in the blackout, Cortinas pointed out that “the question is not whether or not there are renewables,” but rather how voltage control was carried out on the grid that day, which he cited as one of the key issues that would explain the historic blackout. According to the report prepared by REE, there were “breaches” by the generators in this voltage control. But the government also pointed to “insufficient” planning by REE the day before in selecting the power plants that were to control voltage (and charge for it).»

The ENTSO-E “final report” will be presented in early 2026 with a “detailed analysis” of the “root causes” of the blackout, for which data is still lacking: they will analyze how voltage control was carried out that day and the “local oscillation” that caused a large Iberdrola photovoltaic plant to fail at 12:03 p.m. — The blackout report detects power plants that “were not regulating voltage” and an “improper” disconnection of facilities

Antonio M. Vélez / Rodrigo Ponce de León October 3, 2025, 11:01 a.m. Updated on 10/03/2025, 11:37 a.m.

European experts from the European Network of Transmission System Operators for Electricity (ENTSO-E), who, in accordance with EU regulations, presented their “factual report” this Friday on the historic blackout of April 28, have not yet identified those responsible for the incident and have presented a sequence of events similar to that in the report prepared at the time by the Spanish government, which indicated that it was a “multifactorial” event.

The report by the European Network of Transmission System Operators for Electricity, of which Red Eléctrica (REE) is a member, which the electricity companies blame for the blackout, gives itself a period of “four months” from the publication of this “factual report” to publish a “final report” in the first quarter of 2026. This is because some information is still missing.

The report notes that, 158 days after the serious incident that left the entire Iberian Peninsula in darkness, “some data is still missing, particularly related to some of the generation losses that occurred before the blackout.”

During the presentation of the report, ENTSO-E officials indicated that they had encountered “significant difficulties” in obtaining information from several generating companies in Spain, according to Kaschnitz. It should be remembered that in June, the government sent letters to the sector expressing its ‘concern’ about the “slowdown” in the submission of data for the report that was then being prepared by an interministerial commission.

This final report by ENTSO-E will include a “detailed analysis” of the “root causes,” the “voltage control” carried out on the grid that day by the generators, “the behavior of different actors during the incident,” and some “additional” comments.

Among them, on the causes of the “local oscillation” which, as revealed by elDiario.es, was at the origin of the blackout and was caused by Iberdrola's Núñez de Balboa mega-photovoltaic plant at 12:03 that morning (which the report does not mention). This oscillation was an “unusual” phenomenon, as pointed out by the Austrian expert who co-led the panel, Klaus Kaschnitz.

The report notes that the blackout, a unique event in the world, was due to a “surge cascade” that began in southern Spain and spread throughout the peninsula in a matter of minutes. “The problem here is not that there were renewables, but that we need generation that has voltage control. The good news is that this can be done in the same way as in conventional generation,” explained Entso-E president Damián Cortinas, when asked about the responsibility of green generation sources.

The ENTSO-E report explains that the morning of April 28, 2025, was characterized by “increasing renewable generation,” which led to “a decrease in daily market prices and an increase in exports from Spain” to a total of five gigawatts. From 9:00 a.m., voltage variability in Spain began to increase until shortly after 10:30 a.m., “when the voltage in part of the 400 kV transmission network briefly approached, but did not exceed, 435 kV,” within the permitted values.

The Austrian expert who coordinated the report explained that April

The report confirms that there were no “significant oscillations” in the grid until 12:03 p.m., when the first oscillation began, which the government and REE reports attributed (without expressly citing it) to the Núñez de Balboa megaplant.

This was an initial oscillation of a “local nature” preceded by a second, broader oscillation of an inter-area nature, corresponding to the East-Central-West zone of the European electricity system. The measures taken by the system operators in Spain, Portugal, and France (including a reduction in the flow of energy between Spain and France) mitigated these oscillations, but led to an increase in voltage in the Iberian system, although still “within operational values.”

Subsequently, once facilities began to disconnect, “given that some generation units were consuming reactive power,” the opposite of what they were supposed to do, “with the effect of reducing voltage, the disconnections of these units without adequate compensation for the loss of reactive power by other system resources with the capacity to inject/absorb reactive power led to an increase in voltages in the system, not only in Spain but also in Portugal.”

Starting at 12:32 p.m., within a span of 57 seconds, 208 MW of wind and solar power in northern and southern Spain, which correspond to the distribution network, were disconnected. There was an increase in the net load on the distribution networks of around 317 MW, which “could” be due to the disconnection of small self-consumption installations, although the reasons are “unknown.” The voltage began to rise “really fast,” explained the Austrian expert.

From 12:32:57 p.m. onwards, there were major power disconnections in Granada, Badajoz, Seville, Huelva, and Cáceres. At least 2 gigawatts were lost, milliseconds after the protection devices of a transformer in Granada, which connects several generation facilities there and was injecting 355 MW at the time, were triggered.

Reasons “unknown”

Another 725 MW of photovoltaic and solar thermal power was then lost in Badajoz, along with wind and solar disconnections in Segovia, Huelva, Badajoz, Seville, and Cáceres for another 1,200 MW. “Some of these disconnections were due to surge protection,” but the reasons for “most of them are unknown,” the document says.

Between 12:33:18 and 12:33:21, the voltage in southern Spain rose sharply and, as a result, also in Portugal. The overvoltage caused a cascade of generation losses, which led to a decrease in the frequency of the Spanish and Portuguese electricity systems. At 12:33:19, the Spanish and Portuguese electricity systems began to lose synchronism with the rest of the European system, the interconnections with Morocco and France were tripped, and absolute zero occurred.

This report will be supplemented by the one being prepared by the Spanish regulator, the National Commission for Markets and Competition (CNMC), which has also participated in this panel of experts.

As explained by the president of ENTSO-E, this “factual report” does not seek to place “any responsibility” on any agent in the sector, but rather to trace a “sequence” of events.

When asked about the role of renewable energies in the blackout, Cortinas pointed out that “the question is not whether or not there are renewables,” but rather how voltage control was carried out on the grid that day, which he cited as one of the key issues that would explain the historic blackout. According to the report prepared by REE, there were “breaches” by the generators in this voltage control. But the government also pointed to “insufficient” planning by REE the day before in selecting the power plants that were to control voltage (and charge for it).

The report was prepared by a panel of 45 experts, the largest ever formed, including both system operators and national regulators from across Europe, and was led by two experts from Austria and Hungary. After five months of “intense work,” it will form the basis for recommendations to be implemented in the near future.

"This is the report paid for by Iberdrola and Endesa. Coincidentally, it was presented three days before the official ENTSOe report."

No blame on renewables.

The IIT presents a preliminary report analysing the causes of last April's blackout 29 September 2025

Large voltage fluctuations, low synchronous generation and a weak transmission network are some of the causes

The Institute for Technological Research (IIT) at Comillas Pontifical University—one of Europe's leading electrical systems research centres—has today published an independent preliminary report analysing the causes of the blackout that left the Iberian Peninsula without power on 28 April. The document, prepared by professors Luis Rouco, Enrique Lobato and Francisco M. Echavarren, concludes that the blackout was the result of a combination of voltage instability in the previous days, insufficient synchronous generation, an insufficient safety margin against overvoltage collapse and a weak transmission network, aggravated by the disconnection of renewable generation and operational manoeuvres that reduced the safety margin.

The analysis reveals that synchronous generation (mainly combined cycle and nuclear power plants) in the southern and central areas was unusually low, with only one combined cycle plant in Andalusia and one nuclear plant in the centre. In addition, more than a third of the 400 kV grid was disconnected for maintenance or voltage control, leading to poorly damped oscillations.

The report introduces the concept of ‘overvoltage collapse’, a phenomenon unprecedented in Europe, where voltage increases uncontrollably when renewable generation is disconnected. It adds that the cascading overvoltage that occurred is unprecedented in the European electricity system.

The researchers also emphasise that the manoeuvres carried out by Red Eléctrica de España between 12:00 and 12:30 —connecting lines to try to dampen the oscillations— further reduced the safety margin, accelerating the collapse of the system.

The IIT recommends reviewing the criteria for synchronous generation scheduling and voltage control procedures, especially in scenarios of high renewable penetration, and urges the use of more advanced metrics to anticipate risk situations. The report also highlights the importance of strengthening coordination between the various players in the electricity sector and adapting the operation of the system to the new challenges of the energy transition, with the massive integration of renewables.

Translated with DeepL.com (free version)