Incident overview On 28 April 2025, shortly after 12:30 CET (11:30 Irish Time), a significant incident occurred in the power systems of Spain and Portugal, causing a sudden loss of approximately 15 GW of generation output within about 5 seconds. This incident led to a blackout affecting both countries, with some areas near the border of France also experiencing disruptions, albeit for a brief period. The Spanish Transmission System Operator linked the cause of this blackout to “very strong oscillation
