Some Mondays are worse than others, but April 28 2025 was particularly bad for millions of people in Spain and Portugal. Starting just after noon, a number of significant grid oscillations occurred which would worsen over the course of minutes until both countries were plunged into a blackout. After a first substation tripped, in the span of only a few tens of seconds the effects cascaded across the Iberian peninsula as generators, substations, and transmission lines tripped and went offline. Only after the HVDC and AC transmission lines at the Spain-France border tripped did the cascade stop, but it had left practically the entirety of the peninsula without a functioning power grid. The event is estimated to have been the biggest blackout in Europe ever.
Following the blackout, grid operators in the affected regions scrambled to restore power, while the populace tried to make the best of being plummeted suddenly into a pre-electricity era. Yet even as power gradually came back online over the course of about ten hours, the question of what could cause such a complete grid collapse and whether it might happen again remained.
With recently a number of official investigation reports having been published, we have now finally some insight in how a big chunk of the European electrical grid suddenly tipped over.
Continue reading “The 2025 Iberian Peninsula Blackout: From Solar Wobbles To Cascade Failures”