Some in Spain, Portugal and some Southwestern France suffered huge cuts on Monday, with major cities including Madrid, Barcelona and Lisbon being affected.
Houses, offices, trains, traffic lights and even the Madrid Open Tennis Championships have been hit, causing chaos for millions and prompting contenders of Spanish and Portuguese governments and network operators to understand and compete to resolve the issue.
The electric red of the Spanish Grid's España (REE) indicates that Spain and Portugal were hit by "El Cero" - zero. Its Portugal peer National Energy Network (REN) said the power outage began at 11:33 a.m. in the summer in Western Europe.
By mid-afternoon, the Spanish operator was partly state-owned, and it had begun to retract voltages in the northern, southern and western parts of the Iberian Peninsula. The recovery process can only be done step by step to avoid overloading parts of the grid when each generator is connected.
Spain's largest energy utility, Endesa, with 10 million customers, and Iberdrola, the second largest provider, said they are working with REE under the established agreement.
Portuguese Prime Minister Luís Montenegro said the issue originated in Spain. Ren from Portugal said that "rare atmospheric phenomena" have caused severe temperature imbalances, leading to widespread closures.
"Abnormal oscillations occur in very high voltage lines (400 kV) due to extreme temperature changes in internal or Spain, a phenomenon known as "induced atmospheric vibrations." These oscillations lead to failure of synchronization between electrical systems, resulting in continuous interference from the Internet network," Ren said.
Georg Zachmann, a senior researcher at Brussels IQ, said it was unclear what caused the initial problem, but since then the system suffered a "disconnection from power plants" including one in France - including one in France - where the frequency of the grid dropped below 50 Hz (European Standard).
European Council President António Costa, who served as Portugal's prime minister from 2015 to 2024, said: "There is no evidence that this is a cyber attack", but warned that the ultimate cause is still unclear. Teresa Ribera, Vice-Chairman of the European High Commission, also told Spain Radio 5 that there was no evidence that intentional behavior caused the power outage.
However, the Spanish National Security Council convened on Monday to assess the power outage. Montenegro, Portugal, said it was too early to determine what caused the power outage.
Spain is becoming a green energy leader: it has a lot of sunshine and wind. Last year was a record-breaking period of renewable power generation, accounting for 56% of all electricity used. By 2030, that percentage will rise to 81%.
This shift will help Spain end its dependence on energy imports, but it also brings its own challenges. Every national grid in the world needs to spend a lot of money to upgrade distribution systems to connect sporadic renewable energy sources and ensure their balance.
The grid needs constant management to ensure that it is not generated too much or too little left. If the frequency breaks beyond the normal range, the power station will automatically turn off. To restart, they must be reconnected to the user.
As long as there is a grid, balance is important, but there is more attention to this issue due to the rapid conversion to solar and wind (such as solar and wind).
Rotating gas turbines have been the standard technology for managing frequencies for decades, but renewable energy requires investment in other options such as flywheels or advanced power electronics.
"You can't ignore it," Zachman said. "You need tools to keep the system running."
Taco Engelaar, managing director of Keara Anewa, an energy utility software provider, said the widespread failure was “very unusual.” However, there were examples before. In 2003, there was a problem with the hydraulic lines between Italy and Switzerland, causing about 12 hours of power outages throughout Italy. Germany's electricity overload in 2006 caused disruptions as far as Portugal and Morocco.
"Interconnection between countries is crucial to sharing clean energy, but it also creates new avenues for the failure to spread quickly," Englar said.
But, Bruegel's Zachmann said interconnections also help prevent the problem from worsening. Interconnects with France will make it easier to restore the power system. "Yes, the problem overflows, but at the same time, larger systems act as buffers and prevent the crisis from escalating," he said.