Power is gradually being restored across Spain and Portugal after a sudden and unprecedented blackout swept through the Iberian Peninsula on Monday, severely disrupting public life. The outage affected major airports, halted public transportation, and suspended routine operations in hospitals, prompting both governments to initiate emergency responses.

Spain’s Interior Ministry declared a national emergency and deployed 30,000 police officers across the country to maintain order. Emergency cabinet meetings were held in both countries to coordinate efforts in handling what is now considered one of the most significant power failures to hit Western Europe in recent history.

While the exact cause remains under investigation, differing accounts have emerged. Portuguese officials suggested the problem originated in Spain, while Spanish authorities pointed to a sudden disconnection from the French grid. Spanish Prime Minister Pedro Sánchez stated that the country suffered a catastrophic loss of 15 gigawatts of electricity generation—approximately 60% of national demand—within just five seconds. He called the event unprecedented and confirmed that NATO had been alerted as a precautionary measure. Although Portuguese Prime Minister Luís Montenegro reported no indication of a cyberattack, speculation about possible sabotage has continued to circulate.

João Conceição, a board member of Portugal’s national grid operator REN, suggested that a massive voltage oscillation in Spain may have triggered a chain reaction that rapidly overwhelmed Portugal’s power system. Spain’s national grid operator, Red Eléctrica de España (REE), described the failure as “extreme and unprecedented,” blaming a disconnection with France that overwhelmed system defenses. France’s electricity operator RTE later confirmed it had provided emergency power to northern Spain to help stabilize the situation.

By Monday night, electricity had been restored to approximately 61% of Spain, including parts of Madrid, Barcelona, and the Basque Country. In Portugal, REN reported that 85 of 89 substations were back online, including those servicing the capital, Lisbon. Madrid’s mayor urged residents to remain indoors, citing safety concerns due to unlit streets and the need for emergency services to operate without obstruction.

This rare event has exposed the fragility of Europe’s interconnected energy infrastructure and is expected to spark renewed debate around grid resilience, regional self-sufficiency, and the need for modernized systems capable of preventing cascading failures on such a massive scale.