One year ago, the lights went out across Spain and Portugal in one of the worst blackouts in European history. On April 28, 2025, at 12:33 CEST, the Iberian Peninsula lost 31 gigawatts of power in just five seconds. Most people were without electricity for about ten hours. Some waited even longer.
On April 28, 2025, the Iberian Peninsula lost 31 gigawatts in five seconds — one of Europe’s worst blackouts ever.
The trouble reportedly started with a substation failure in Granada province. Grid failures then reportedly hit Badajoz and Sevilla. A large generator in southwestern Spain tripped, causing frequency to drop fast. Cascading generation disconnections, including renewable energy sources, followed the initial voltage surge.
At the time of the blackout, solar power was reportedly supplying more than half of Spain’s electricity. Prices had reportedly gone slightly negative just before the event. Engineers later found that voltage and reactive power controls weren’t working well enough. Fast voltage swings caused a chain reaction of failures. Overvoltage alone caused an estimated 1 GW generation drop.
At least seven people died in Spain and one in Portugal from incidents tied to the outage. Telecommunications, transportation, and emergency services were all severely affected. A small area of southwestern France near the Spanish border also saw brief disruptions.
Restoration efforts began using interconnections with France. Workers brought back power to Aragón-Cataluña and Galicia-León first. Spain imported roughly 15 GW from France to help rebuild the grid. Within an estimated 9.5 hours, roughly 62% of Spanish substations were re-energized. Full restoration in Spain was completed within 24 hours. Portugal’s recovery moved faster, with 96% of transmission substations restored within 10.5 hours and all load reconnected within approximately 12 hours.
One year later, the Expert Panel’s investigation did not assign responsibility to any single person or organization, instead identifying multiple interacting technical and operational factors. Spain’s grid operator REE ruled out a cyberattack. An expert panel found multiple interacting causes but didn’t blame any single person or group. The Spanish government formed an inquiry commission, and ENTSO-E released its final report in March 2026. The report included recommendations but stopped short of assigning responsibility. Investigators noted that vulnerable populations were disproportionately affected, with emergency services struggling to reach those most in need during the outage.
Meanwhile, Spain’s renewable energy expansion continues. Critics say the grid’s ability to handle that growth still hasn’t been fully addressed.
References
- https://en.wikipedia.org/wiki/2025_Iberian_Peninsula_blackout
- https://www.powermag.com/understanding-the-april-2025-iberian-peninsula-blackout-early-analysis-and-lessons-learned/
- https://www.entsoe.eu/publications/blackout/28-april-2025-iberian-blackout/
- https://www.youtube.com/shorts/GIQIh5HooM8
- https://eepublicdownloads.blob.core.windows.net/public-cdn-container/clean-documents/Publications/2025/iberian-blackout/Final Report on the Grid Incident in Spain and Portugal on 28 April 2025.pdf
