On Monday, a widespread blackout affected large parts of the Iberian Peninsula, primarily due to a significant and sudden reduction in electricity supply, according to Spain’s grid operator, REE. The incident caused a disconnection between the Spanish and French power grids, leading to a collapse of Spain’s electricity network.

People use their mobile phone's flashlights to walk in the dark during a nationwide power outage in Madrid, Spain, April 28, 2025.

At approximately 10:33 GMT, the grid experienced a rapid loss of 15 gigawatts of power generation within five seconds, as reported by the Energy Ministry on Monday evening. The ministry did not specify the cause of this substantial power drop.

Eduardo Prieto, REE’s system operations chief, addressed the media, stating: “As the result of this disconnection and the serious imbalance of band generation that is in our electrical system, the electrical system collapsed.” He noted that the scale of the power loss exceeded the capacity that European grid systems are designed to manage, triggering the disconnection of the Spanish and French grids.

Prime Minister Pedro Sanchez, in a national address, indicated that the precise reasons for the significant power loss remained unclear. REE staff have not identified the root cause, and all possible explanations are still under consideration.

The blackout, which lasted several hours, caused widespread disruptions across Spain and Portugal. Power restoration efforts began promptly, and by Monday evening, electricity was gradually restored to most areas in both countries.