The Iberian Peninsula experienced a massive and historic blackout on Monday, which left the mainland territories of Spain and Portugal without electricity for hours. “In my more than 40 years in this sector, I have never seen anything like this,” said Jorge Fabra, who for a decade president of Red Eléctrica, the public company that operates the national electricity grid in Spain. In the afternoon, electricity was beginning to be restored in some parts of the country. However, the main question that remains is what exactly happened. “We do not rule out any hypothesis,” said Pedro Sánchez, the country’s prime minister, at a press conference at around 6 p.m. local time “We do not know the causes,” he insisted, thus further increasing the uncertainty surrounding the historic energy collapse.

This is what is known and what is not known about the incident as of Monday afternoon.

When did the power outage start?

At 12:32 p.m. local time, “a very strong fluctuation in power flows” was detected in the electrical grids. This fluctuation was due to a loss of generation, meaning a drop in electricity production, which in Spain comes mainly from nuclear plants, hydroelectric plants, combined cycles, and solar and wind farms.

This power loss was caused by the sudden disappearance of 15 GW of generation for five seconds. To understand the scale of the problem, the five nuclear power plants in Spain have a combined installed capacity of 7.4 GW.

The fluctuation caused by this drop, the causes of which are still being investigated, triggered the disconnection of the Spanish electrical system from the European grid, which relies on an interconnection with France. This disconnection “led to the collapse” of the system and the subsequent widespread blackout, according to Eduardo Prieto, Director of Operations Services at Red Eléctrica, in an initial press conference at 2:30 p.m. Later, at 7:00 p.m., Prieto reiterated this explanation and emphasized that this is an “absolutely exceptional event,” of a dimension never before seen in Spain.

When will the problem be solved?

Prieto had stated at 2:30 p.m. that the full recovery of service in Spain would take between six and ten hours, and that it would be “gradual and progressive.” However, during the afternoon briefing, he no longer specified the number of hours required for the system to be fully restored.

The Spanish government has declared an electricity crisis following the interruption of the power supply, and work has begun to restore the service.

Technicians from Red Eléctrica and electric companies are now working on restoring the voltage, starting in areas close to France. Once the voltage is restored in the system and delivered to the plants, they can start to bring things back to normal. By 5:30 p.m., electricity had been restored in areas of Catalonia, Aragón, the Basque Country, Galicia, La Rioja, Asturias, Navarre, Castile and León, Extremadura, and Andalusia, according to Red Eléctrica. By 6:45 p.m., areas including Madrid, the Valencian Community, Murcia, and Castile-La Mancha had begun to have the power restored. By 9:30 p.m., according to Prieto, 35% of the supply was already covered.

What caused the system collapse?

Neither Prime Minister Sánchez, Prieto, nor any official source has explained what caused this unprecedented energy shutdown. “We are not going to speculate,” insisted official government sources. During his brief statement without taking questions, Sánchez emphasized the need to avoid spreading “information of questionable origin.”

Was it caused by a meteorological phenomenon?

Various hypotheses have emerged about the cause of the blackout, some of which have been debunked.

Reuters reported that REN (Redes Energéticas Nacionais, the equivalent of Red Eléctrica in Spain) had suggested that a strange meteorological phenomenon in Spain could be the origin of the blackout. However, sources from this organization have denied that information, which pointed to a supposed temperature variation in the interior of Spain.

Could it have been a cyberattack?

Since the massive blackout occurred, it has been speculated that it could have been caused by a cyberattack. The first to assert this most firmly was the premier of Andalusia, Juan Manuel Moreno, who stated that, according to information from the regional cybersecurity center, “everything points to the fact that a blackout of this magnitude could only be due to a cyberattack.” Moreno, however, acknowledged that he had reached this conclusion without confirmation from La Moncloa or another institution. A couple of hours later, the Vice President of the European Commission, Teresa Ribera, stated in Brussels that, after being in contact with Spanish and Portuguese authorities, there were no “indications that [the blackout] was deliberately caused.”

The National Cryptologic Center, which operates under the National Intelligence Center (CNI), has limited itself to saying that it is investigating the cyberattack hypothesis. Spain has become one of the countries most targeted by cyberattacks considered critical due to their severity, with several hundred each year. The Joint Cyber Command, which is under the Ministry of Defense, is also investigating the possible cyber origin of the blackout.

Would a cyberattack of this scale be possible?

The preparation and execution of a cyberattack that shuts down the electricity of almost two entire countries is very complex. It requires a coordinated operation that achieves several objectives simultaneously. “A blackout of this scale through a cyberattack would be complicated because there are many segmented electrical networks,” said Martín Vigo, a cybersecurity specialist. And once it happens, analyzing the networks to find the origin of the attack is not easy either. “Cyberattacks on electrical networks are possible both in theory and in practice because energy infrastructures are very complex systems, full of vulnerable points,” said Lukasz Olejnik, an expert from King’s College London. “An attack, for example, could target transformers or substations, causing damage to hardware until it starts to fail. But coordinating such a large and synchronized attack would be extremely difficult.”

Has an attack like this happened before?

So far in Spain, there is no indication that something like this has occurred. The only successful attacks of this scale took place in Ukraine in 2015 and 2016, with Russia being the culprit. “Other cases were simply demonstrations, failed attempts, or mere rumors,” said Olejnik. The official teams responsible for investigating whether there has truly been an attack have all the necessary tools to find out if it did happen: “Speculating now is not very useful: we simply don’t have enough data,” added the expert. “There is no ‘clear symptom’ that would allow us to say with certainty that a blackout like this is due to a cyberattack. Everything we’ve seen so far could also be explained by normal, non-malicious causes. That’s why it’s important to investigate and avoid falling into rumors or misinformation.”

The National Cybersecurity Institute (INCIBE) warned a year ago about the “significant increase in cyberattacks affecting industrial environments and critical systems.” The institution cited the malicious software BlackEnergy as an example, which was used by Russian hackers on December 23, 2015, to sabotage the electricity distributors in the Ukrainian region of Ivano-Frankivsk, causing a blackout that affected 1.5 million people.

The National Security Department (DSN) of the Prime Minister’s Office also warned in its latest report about the “increase in the number, frequency, sophistication, and severity of cyberattacks.” In 2023, the National Cryptologic Center managed about 108,000 incidents; INCIBE handled 83,500; and the Joint Cyber Command of the Ministry of Defense dealt with 1,480. The advisory body to the prime minister warned of the existence of “increasingly sophisticated attackers and growing interconnectivity, which broadens their potential range of action.”

The worst power blackout in Spain’s recent history has affected, since noon local time, millions of citizens throughout the country as well as Portugal. The power cut has paralyzed the normal functioning of infrastructures, telecommunications, roads, train stations, airports, stores, and buildings. Hospitals have not been impacted as they are using generators. There is still no official explanation for the massive blackout. Authorities have not ruled out a cyberattack as both the Spanish and Portuguese governments investigate the cause.

Red Eléctrica, the public company that operates the national electricity grid in Spain, emphasized the unprecedented nature of the situation: “Such an event has never occurred before; it is an absolutely exceptional incident.” According to the grid operator, starting at 13:00 (7:00 a.m. EST), efforts began to restore voltage in the northern and southern parts of the peninsula, “which is key to progressively restoring the electricity supply.” Eduardo Prieto, Director of Operations Services at Red Eléctrica, stated that full service recovery will take between six and ten hours, which, if confirmed, would mean that power would be restored across the country between nine in the evening and one in the morning.

The outage has suddenly set Spain back to the 19th century. Traffic lights out of service, traffic jams forming across the country, pedestrians wandering around cities without public transportation, desperate families trying to communicate with their loved ones, passengers left stranded without trains or flights, canceled medical appointments, rescues underway in subway stations and elevators, lines forming outside small shops due to supermarket closures… These were some of the scenes left by the unprecedented event on Monday.

The urgency of the incident has led the authorities to make it the only topic on the agenda. Spanish Prime Minister Pedro Sánchez held a meeting at the Control Center of Red Eléctrica, where Deputy Prime Minister Sara Aagesen and several other ministers were also present. The National Security Council has also called a meeting. At the regional level, local governments are also mobilizing. Catalan regional premier Salvador Illa held a meeting with the crisis cabinet at the Palau de la Generalitat de Catalunya. Other regions, such as Andalusia and the Basque Country, have done the same.

Red Eléctrica indicated that the process of restoring the supply will “involve the gradual energization of the transmission network as the generation units are reconnected.” They added that they continue “working to restore the supply.” For his part, Prieto said that the company’s technicians are “focused on restoring the supply so that the impact on society is as minimal as possible.” However, he did not want to point to possible causes: “There is no information on the cause of the incident, and we cannot speculate about its origin. Everything will be analyzed in detail.”

Citizens from all Spanish regions and from Portugal reported widespread power outages shortly after noon. According to major Spanish electric companies consulted by EL PAÍS, no explanation has yet been provided for the blackouts. The Adif railway network experienced voltage losses, leading to the suspension of train traffic across the country. Renfe announced through its social media accounts that there has been no train movement or departures from stations since 12:30. Various airlines reported disruptions at airports such as Madrid-Barajas and Barcelona-El Prat as power supply is being restored. Air traffic controllers have reported traffic regulations or reductions at the two major hubs on the peninsula: Madrid-Barajas and Lisbon. Confusion reigns among airlines and travelers.

The blackout is also affecting telecommunications. There are widespread problems making phone calls, and the WhatsApp messaging service is operating at reduced capacity. Major telecommunications companies like Telefónica and Masorange are investigating the situation and working to restore service as quickly as possible. The internet can work for a few hours without electricity, but not for much longer. While data centers are protected by their own backup generators, the network relies on intermediate systems that have a shorter autonomy.

Non-urgent medical interventions are suspended

Spain’s healthcare system is currently functioning, as hospitals are equipped with backup generators for power outages, which can keep essential equipment such as ventilators, heart monitors, and other vital medical devices running for hours. Although some facilities in certain areas may experience power loss, it should not affect critical care. A spokesperson for the Gregorio Marañón Hospital in Madrid explained that an emergency committee has been activated to make decisions depending on how long the electrical failure lasts, but emphasized that patient care is fully covered. At the 12 de Octubre Hospital in Madrid, where emergency systems have also been activated and power is available, a spokesperson indicated that surgeries already underway have continued, while those that had not yet started have been suspended for the time being, except for urgent cases. The Hospital del Mar in Barcelona is operating normally.

Due to the widespread blackout on the mainland, Spain’s Directorate-General for Traffic is asking the public to avoid using their cars except in cases of extreme necessity, due to the risk of accidents. “The lack of electricity supply prevents the operation of traffic lights and signage panels.” In some areas, police officers are manually directing traffic.

In Madrid, the Metro service has been suspended due to “external causes” related to the power outage, according to a message posted on X. Likewise, the Madrid Cercanías commuter rail network is out of service due to the lack of electricity. Additionally, 150 elevator incidents have been reported in the city, according to the mayor, José Luis Martínez-Almeida.

Factory lines come to a halt

In addition to infrastructure, commerce, and telecommunications, large industries are also struggling to continue their operations. Car manufacturers Seat and Ford have stopped their production lines. As this newspaper has been able to confirm, the Ford Almussafes car plant is currently without power and with the production lines completely stopped. “The workers are scared, they don’t know what has happened,” says a company spokesman. Truck manufacturer Iveco, which has factories in Madrid and Valladolid, has also stopped machines while waiting for the power to come back on.

The Spanish stock exchange (BME) confirms that it is operating normally and that there have been no interruptions in stock market operations. Sources from the National Securities Market Commission (CNMV) indicate that “market infrastructures are functioning normally,” although it is possible that some financial institutions are experiencing connectivity issues that could prevent their clients from operating as usual.

In Portugal, the blackout is also widespread. At the Lisbon airport, thousands of passengers are left in a state of confusion following the power system failure. There has been no official explanation yet from the Portuguese government regarding the failure in the country’s electrical grid, which is also affecting the telecommunications network. Red Eléctrica Nacional, the company that manages distribution in the country, confirmed that this is a widespread failure across the entire territory and that they are investigating the causes. Minister Manuel Castro Almeida stated on the RTP television channel that a cyberattack cannot be ruled out, and that it may be impacting several European countries.

The massive power outage in Spain and Portugal, according to some French media, has only mildly impacted areas near the French border. Cities like Perpignan, according to the newspaper L’Indépendant, have experienced some brief power cuts. Beyond these areas, the country has not faced further disruptions.

Telecommunications in Spain have been seriously affected by the widespread blackout that occurred around midday across the Iberian Peninsula. Numerous users have reported problems making calls, with many unable even receive dialed carrier calls. Meanwhile, the WhatsApp messaging service is operating at half speed. Some users are able to send messages, but many others are unable to even receive them, and are completely cut off. Numerous users are reporting on social networks like X (formerly Twitter) that their data services are functioning erratically.

Major Spanish telecom companies such as Telefónica and Masorange are studying the incident and working to normalize service as quickly as possible. For its part, Finetwork has already notified its customers of the problems. This newspaper has attempted to contact these companies, but has so far been unsuccessful.

Vodafone Spain, for its part, has reported that, due to circumstances beyond the company’s control, there has been a massive power outage across most provinces in Spain, impacting communications and infrastructure. Vodafone’s mobile network is currently operating at 70% capacity, thanks to backup generators, but how the network remains operational will depend on how long the outage lasts.

At the same time, measures are being taken to maintain communications for as long as possible, prioritizing and managing network resources and capacity in the most efficient way. “Vodafone Spain is advising customers who still have mobile service to use it responsibly and avoid overloading the network,” the company said.

For this same reason, Madrid’s 112 emergency service has requested that people avoid calling unless absolutely necessary. “We are operational thanks to our own backup generators. Please use 112 only for emergency calls,” the service said in a tweet.

In Barcelona, the city council said that Mayor Jaume Collboni is presiding over the CECOR, Barcelona’s operational emergency coordination center, which was urgently convened “to monitor the impacts caused by the lack of power supply and disruptions to telecommunications.”

As for the Internet, experts such as Arturo Azcorra, deputy director of Imdea Networks, warn of its dependence on what are known as intermediate clusters or data switches that are scattered throughout cities, which can only last a few hours without power. This would bring down the network, even though large data centers are protected with clusters of their own that can run indefinitely. “It is as if the central nervous system worked, but not the peripheral one,” says Azcorra.