BLACKOUT SWEEPS SPAIN AND PORTUGAL: WHAT WE KNOW SO FAR ABOUT THE POSSIBLE CAUSES

MADRID, SPAIN • A massive power outage struck Spain shortly after 12:30 PM today, impacting neighboring Portugal and parts of France. Spanish authorities urged citizens to stay home as the blackout halted metro systems in major cities, disrupted traffic lights, and affected airports. While initial investigations point to a technical fault, no hypothesis, including cyberattack or infrastructure failure, has been ruled out.

Madrid, Spain, April 28, 2025 – 9:32 PM – A widespread power outage hit Spain today shortly after 12:30 PM, with ripple effects in neighboring Portugal and some areas of France. Spanish authorities urged citizens to remain indoors. The power cut brought Madrid, Barcelona, Valencia, and Seville metros to a halt, threw traffic lights into chaos, and left Barajas Airport without electricity. The outage also caused problems for telephone lines. Seville erupted in applause at 3:56 PM when power was restored after more than four hours of city-wide disruption. But what caused the blackout? Here are the hypotheses and what we know.

What We Know So Far

ENISA's Initial Findings

According to the European Union Agency for Cybersecurity (ENISA), initial investigations into the cause of the outages suggest a technical fault rather than a cyberattack. "For now, the investigation seems to point to a technical issue or a cable problem," an agency spokesperson said in an email statement to Bloomberg. "However," they added, "ENISA is closely monitoring the situation, and we are in contact with the relevant national and EU authorities."

Spanish Government's Investigation

The Spanish Government has launched an urgent investigation involving technical teams from various ministries to clarify the origin of the outage. Spanish authorities also recommended not driving until electricity was restored. In Seville, tourists in the streets and residents leaning out of windows greeted the return of power with cheers of approval. All major tourist attractions were unable to absorb the massive influx of visitors who had flocked to the streets.

Premier Sánchez: "No Hypothesis Excluded"

For his part, Spanish Prime Minister Pedro Sánchez stated that he "does not rule out any hypothesis" regarding the causes of the blackout affecting the Iberian Peninsula. He urged citizens to pay attention only to news disseminated through "official channels." Sánchez declared that hydroelectric plants are now operational and expressed confidence that supply would be restored "soon," though he did not specify a timeline.

Portuguese Grid Operator Cites "Extreme Temperature Variations"

"Extreme temperature variations in Spain" may have contributed to the blackout across the Iberian Peninsula, according to Portuguese grid operator Ren, as cited by the BBC. "Due to extreme temperature variations in the Spanish hinterland, anomalous oscillations occurred in the extra-high voltage lines (400 kV), a phenomenon known as 'atmospherically induced vibration'," Ren stated. "These oscillations caused synchronization failures between the electrical systems, leading to subsequent disturbances along the interconnected European network."

No Critical Issues for Italy

Regarding the blackout in Spain and parts of Portugal and Southern France, Terna, the Italian company that manages the national electricity transmission grids, reported that no operational criticalities were detected on the national electricity transmission network.

Expert Opinion: Potential Causes

"The situation is very serious, and we are navigating in the dark: at the moment, there are no indications about the causes that triggered the collapse of the electrical system. But nothing can be excluded, from a cyberattack to sabotage, or even some vital transmission infrastructure," previously stated Davide Tabarelli, an expert from Nomisma Energia. He added that potential causes could also include "a fire in southeastern France that put an import line out of action."

Blackout Impacts in Spain

The massive blackout caused problems at Madrid airports and for trains across much of the Iberian Peninsula, where rail traffic came to a halt. Metro systems also stopped. Flights were grounded at Madrid Barajas and Lisbon airports, while flight cancellations were reported at Barcelona-El Prat. The National Cybersecurity Institute (Incibe) has also opened an investigation into the widespread power cut to determine if it was caused by a cyberattack.

Islands Excluded from Blackout

The general blackout did not affect the Canary Islands and the Balearic Islands, which have independent electrical systems from the Iberian Peninsula, according to local sources reported by El Pais. Among the potential causes hypothesized, as also reported by Nomisma Energia expert Tabarelli, was a fire that developed on Mount Alaric in France, which may have damaged the high-voltage line between Perpignan and east of Narbonne.

Blackouts Due to Grid Imbalances

Blackouts like those in Portugal, Spain, and Southern France occur when strong frequency oscillations happen on the electrical grid, meaning they fall outside the European standard of 50 Hertz. This is the frequency that ensures the regular operation of appliances and electronic devices, and any deviation from this value can cause malfunctions. As for the causes of the oscillations, only hypotheses are currently possible, said Alberto Berizzi, professor of electrical power systems at Politecnico di Milano.

What Might Have Happened

Berizzi also explained that "when frequency oscillations occur, cascading events are possible as protective mechanisms for power lines are triggered." These mechanisms are designed to ensure the safety and stability of the electrical system. According to the expert, it cannot be ruled out that protective mechanisms were activated that separated the electrical grid of Spain and Southern France from the European grid.

Wind and Photovoltaic as Contributing Factors?

Professor Berizzi urged consideration that "the Spanish electrical grid has a particular structure, with a lot of production from wind and photovoltaic sources: both these sources are good for decarbonization, but they are more delicate for grid stability. That's why work is ongoing to integrate them as much as possible."

What Happened in France

Several municipalities in southern France, not far from the Spanish border, particularly in Occitania and especially in the Perpignan area (known as French Catalonia), also lost power. According to the French electricity operator, some homes "were deprived of electricity supply for a few minutes in the French Basque Country," but "everything was immediately restored." According to the French operator, the Iberian grid was automatically disconnected from the European grid from 12:38 PM to 1:30 PM, at which time the 400kV power line operating between French and Spanish Catalonia was restored.

What Happened in Portugal

The blackout also affected Portugal starting around 11:30 AM (Lisbon time). The Portuguese Civil Protection reported, however, that redundancy systems continued to function normally. Hospitals also experienced no problems thanks to electric generators, although some, like São João Hospital in Porto, suspended non-priority activities, while the national medical emergency service recommended that citizens only call 112 in truly urgent cases.

Transport Chaos in Portugal

The transport situation was more chaotic. Access to Lisbon Airport's terminal was restricted to limit passenger entry for flights as much as possible. Lisbon metro stations were also closed, after many passengers had been trapped in train carriages. A company source stated that the situation was later resolved and passengers were brought back to the surface.

Tennis Matches Suspended

Due to the massive blackout, the ATP Masters 1000 and WTA 1000 tennis tournament in Madrid was also temporarily suspended. The ATP Tour stated that two singles matches and one doubles match were underway when the power outage occurred at 12:34 PM local time. The interruption prevented the use of electronic video assistance systems for chair umpires, and a spider cam remained suspended over the court inside the Manolo Santana Stadium. The Prado Museum in Madrid evacuated the public from its crowded halls.