What happened

At 12:33 CEST on 28 April 2025, an overvoltage surge that Spain's grid could not absorb triggered a rapid cascading failure: two earlier periods of grid oscillation were followed by a substation failure in Granada and cascading generation losses in Badajoz and Sevilla provinces, removing about 2,200 MW of generation and causing system frequency to collapse below 48.0 Hz; the AC interconnection lines to France tripped at 12:33:21 CEST and a complete blackout of mainland Spain and Portugal followed within seconds, also affecting Andorra and parts of southwestern France, while the Canary Islands, Balearic Islands, Madeira and Azores were unaffected because they operate independently. Roughly 31 gigawatts of load were disconnected and about 35,000 passengers were stranded on Spanish rail and metro systems. Restoration began with the first 400 kV Spain-France interconnector line re-energized at 12:44 CEST and the Spain-Morocco interconnection restored by 13:04 CEST; Portuguese black-start plants were activated between 16:11 and 17:26 CEST, Portugal's grid was fully restored by 00:22 CEST on 29 April, Spain's grid by around 04:00 CEST, and about 99% of demand was back by 07:00 CEST. Eight deaths were reported across the two countries — seven in Spain (three from carbon-monoxide poisoning linked to a faulty backup generator, one oxygen-dependent patient, one candle-fire fatality, and two others) and one in Portugal (a ventilator-dependent patient whose device's battery backup failed) — along with more than 25 injuries. Business organisation CEOE estimated roughly €1.6 billion in economic losses. Spain's government said in June 2025 there was no evidence of a cyberattack, and grid operator REE attributed the failure to inadequate voltage control by conventional generation rather than to the high renewable-energy share on the system at the time (solar supplied about 59% of generation); EU Energy Commissioner Dan Jørgensen and Spanish Prime Minister Pedro Sánchez explicitly rejected renewable-blame theories, and widely circulated claims attributing the blackout to a Russian cyberattack, solar flares or an atmospheric event were debunked. Spain's parliament established an inquiry committee in June 2025, and the government initially approved (and later repealed) a royal decree-law aimed at grid storage and resilience investment; Portugal announced roughly €400 million in planned grid-infrastructure investment. ENTSO-E's cross-border technical investigation, reported around March 2026, identified 15 contributing factors centered on insufficient dynamic voltage control from synchronous generation and limited transmission resilience, without attributing the event to a single definitive cause or any malicious act.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.