Next April 28 it will be exactly one year of the biggest collapse in our recent history: the great blackout that turned the Iberian Peninsula black and left 55 million people in Spain and Portugal without electricity supply for 12 hours. Almost twelve months later, we finally have the official autopsy.
The final report. The European Network of Electricity Transmission System Operators (ENTSO-E) has made public the long-awaited final report. Throughout 472 pages, the panel of experts dissects an unprecedented event to the millisecond. The document, which warns from its preamble that it does not seek to assign legal responsibilities but rather to learn from mistakes, reveals a chilling diagnosis: the blackout was the perfect storm caused by the rigidity of new technologies, manual ineffectiveness in the face of a millisecond crisis and an infrastructure incapable of keeping pace with the energy transition.
The anatomy of collapse. To understand the ruling, you have to look south. According to the European report, at 12:03 p.m. on April 28 a local vibration was recorded of 0.63 Hz caused by instability in the electronic converters of renewable plants. Minutes later, at 12:19, the swing was amplified, affecting the entire continent. Technical research points to what could be defined as “operational blindness.”
The report notes that much of the renewable generation in Spain operated under a “fixed power factor.” That is, the solar and wind plants were blind to the needs of the grid; they could not absorb reactive energy dynamically. When the voltage rose, these plants were simply taken offline for safety. When they stopped generating electricity, their reactive absorption also suddenly stopped, causing a rebound effect that triggered the voltage in an uncontrolled manner. Furthermore, while the crisis required millisecond reflexes, the control of reactances (the machines that absorb excess voltage) was carried out manually. Operators needed vital minutes to assess the situation.
The blackout that could have been avoided. The European report not only acts as a notary for what failed, but also puts on the table what should have happened. By diving into the technical simulations of the ENTSO-E document, sector experts such as Joaquín Coronado have drawn a devastating conclusion: The collapse of the Spanish electrical system was not inevitable, but the result of ineffective management of voltage control by the System Operator (Red Eléctrica).
The European analysis is blunt. In his simulation of sensitivity (named Analysis 7), the report concludes that if the connection of the reactances – such as the Caparacena shunt reactor at 400 kV – had been automated instead of depending on the slow human factor, the voltage rise would have been limited and the cascade effect avoided. In addition, ENTSO-E simulates alternative scenarios that show that electrical zero would have been stopped cold with measures that should already be operational: an increase in reactive power margins, the requirement that conventional generators absorb more voltage, or the use of the eight new synchronous capacitors that were already planned in the 2021-2026 planning. Without this automated reactive power reserve or dynamic support, the network was orphaned at the worst possible moment.
The rescue from Gipuzkoa. The continental disaster was avoided thanks to Gipuzkoa. At 12:33, the high voltage substation in the Osinaga neighborhood of Hernani detected that the Spanish chaos threatened to drag down all of Europe. In milliseconds, the protection relay out-of-step (out of step) decapitated the connection with the French Argia substation. This “shot” left Spain in the dark, but it shielded the continental network. Barely ten minutes later, Hernani became the rescue route, allowing France to inject energy to resurrect the peninsular system from top to bottom (Top-Down).
The structural problem of the market. The targeting of clean energy in the moments before the blackout has raised eyebrows, but the sector defends itself by pointing directly to regulatory inaction. In an interview for XatakaHéctor de Lama, technical director of UNEF (the photovoltaic employers’ association), is blunt: “A plant, no matter how large, cannot cause a blackout. Many other factors must come together.” De Lama explains that the current inverters installed in Spain meet very high European technical requirements, but places the structural problem on the roof of the Ministry (MITECO) and the CNMC for not financially incentivizing renewables to provide security services to the grid.
“The current remuneration of €1/MVArh is not enough to encourage renewables to provide this service (voltage control) when we are paying combined cycle plants between 100 and 200 times more for the same thing,” details De Lama. The UNEF expert also recalls a historical administrative negligence that took its toll on us on April 28: while Portugal approved regulations to take advantage of the voltage control of its renewables in 2019, Spain took years to implement vital mechanisms such as Operation Procedure 7.4. We were playing with the rules of the past in the face of a crisis of the future.
“A gold mine without a road.” This diagnosis fits with the voices of the industry. During the VI Economic Forum of elDiario.esPatxi Calleja, director of regulation at Iberdrola Spain, defined the national system as “a gold mine without a road.” We have enormous cheap generation capacity, but the electricity grid is the great limitation due to lack of investment compared to our European neighbors.
And this green shield also has cracks. As we already analyzed in Xatakathe very high renewable penetration shields us from geopolitical crises (such as the increase in gas prices due to the war in Iran) during daylight hours, plummeting prices to zero. However, as soon as the sun goes down, the lack of mass battery storage sends us back to square one, leaving us at the mercy of combined cycles and fossil volatility.
The war without quarter. While technicians analyze the ENTSO-E simulations that point to operational failures, a fierce battle is being waged in the offices. The president of Redeia (parent company of Red Eléctrica), Beatriz Corredor, has used the Brussels report in her appearances in the Senate to entrench herself and read only the part that suits her: “There is no responsibility on the part of Red Eléctrica,” she assured, blaming the “electrical zero” on the instability of a photovoltaic plant in Badajoz and the non-compliance of conventional generators, just as it appears RTVE.
But REE’s immunity story falls apart. Not only because of the simulations in the European report that show the lack of automation under his command, but also because of some leaked internal recordings. The internal audios, revealed by He Worldshow that the control center technicians had been detecting “oscillations throughout the system” for 15 days and warned that there were “few groups with inertia.” They saw it coming, but they operated manually.
The tension has escalated to the judicial field. An exclusive of The Confidential reveals that Iberdrola and Endesa They have demanded from the judge access to 8,028 calls and 1,296 emails from REE managers from the hours before and after the blackout. Red Eléctrica handed over those files to the Police believing that it was a terrorist cyber attack. When this route is ruled out, REE refuses to let the electricity companies listen to the audios, alleging “national security”, while Iberdrola and Endesa denounce an “exclusionary filter” that prevents them from knowing the truth and, predictably, claiming million-dollar compensation.
The collapse of data and bureaucracy. The blackout not only left homes in darkness; has put Spain’s economic future in check. After the incident, a reinforced control system has been implemented in the network that has already cost more than 800 million euros. A modernization bill that will end up appearing in the pockets of citizens with increases in tolls and charges planned for 2026.
But the problem goes beyond a specific failure: the network is physically saturated. The massive arrival of data centers (energy devourers for Artificial Intelligence) and the new “dynamic criterion” of the CNMC have caused a cascading collapse of the connection nodes. To avoid a new blackout, the Government has urgently demanded that the new facilities withstand “voltage gaps” and not be disconnected in the event of disturbances. All this happens while we suffer an administrative thrombosis. We have 130 GW of renewable generation ready to go but kept in a drawer because processing an electrical line in Spain can take up to ten years.
A system hanging by a thread. Europe has already given us the clinical diagnosis: Spain survived April 28, 2025 thanks to the reflection of a relay in Gipuzkoa and assisted respiration that arrived from France. However, the role of our northern neighbor hides a deep irony. France rescued us from the total blackout, but on a day-to-day basis it is our main commercial executioner.
A year later, the country is still locked in a political and judicial battle over who pays the bill for the collapse, while Iberdrola, Endesa and Red Eléctrica fight in court over thousands of hidden audios. We know automation failed and human operators were too slow, but structural solutions remain bogged down.
Spain has everything necessary to be the great battery and industrial magnet of Europe; But as long as the procedures last a decade, we continue to be isolated by the French border, we lack mass storage and the network operates on the verge of a heart attack, the risk of the electric heart stopping again will continue to beat in the shadows.
Image | Seoane Prado and Robert So
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