On Monday, April 28, 2025, a massive and sudden power outage swept across Spain, Portugal, and parts of southern France. At approximately 12:33 PM CEST, the Iberian Peninsula experienced a dramatic and almost instantaneous loss of around 15 gigawatts of electricity. This figure represents about 60 percent of Spain’s typical demand at that hour. The rapid drop in energy caused Spain’s grid to disconnect from the wider European network, leading to widespread blackouts across major cities including Madrid, Barcelona, Lisbon, Seville, and Valencia.

The impact was immediate and severe. Metro systems in Madrid, Lisbon, and Porto ground to a halt. Airports like Madrid-Barajas and Lisbon-Portela shifted to emergency generators. Traffic across numerous cities became chaotic as traffic lights failed, while hospitals switched to backup systems. The Madrid Open tennis tournament was suspended mid-match, with spectators and players left in darkness. Emergency services responded to thousands of calls, rescuing people trapped in elevators and stalled trains.

Authorities are still investigating the precise cause of the blackout. Early statements from Portuguese grid operator REN suggested that extreme temperature swings across the region may have triggered an unusual atmospheric event. This event, described as an “induced atmospheric vibration,” allegedly caused dangerous oscillations in high-voltage transmission lines, resulting in desynchronization across interconnected grids. Another theory speculated that a fire damaged a major transmission line between Perpignan and Narbonne in southern France. However, France’s electricity operator RTE reported no incidents in that area. Speculation about a cyberattack has been largely dismissed by both Spanish and Portuguese authorities, citing a lack of supporting evidence.

By late Monday evening, power had been partially restored across much of the affected regions. Spanish grid operator Red Eléctrica stated that full service would likely resume within six to ten hours, while REN warned that complete stabilization of the system could take several days.

Comparable Blackouts

The April 28 blackout is already being compared to other significant events in European energy history. In November 2006, a planned shutdown of a transmission line in Germany triggered cascading failures that briefly split Europe’s electricity grid into three separate parts. That event left over 15 million Europeans without power, mostly for under an hour. In 2003, a software failure and tree branch contact in Ohio caused a blackout that affected nearly 50 million people across the northeastern United States and parts of Canada.

What makes the 2025 Iberian event unique is the combination of scale, speed, and the possible role of natural phenomena. While previous blackouts were largely triggered by mechanical or human errors, this incident highlights the vulnerability of even modern grids to extreme weather patterns and unpredictable natural forces. In an increasingly interconnected and electrified Europe, such events underscore the urgent need for reinforcing grid resilience and preparing for new types of systemic risks.

As investigations continue, the April 28 blackout will likely become a major case study in the challenges facing Europe’s energy infrastructure at a time when the continent is transitioning to more complex and decentralized power sources.