The 2025 Iberian Peninsula Blackout
On 28 April 2025, Spain and Portugal: A sudden loss of about 15 gigawatts of generation, more than half of what the two countries were supplying at the time, cascaded into a near total blackout with no single equipment failure to blame.
Key Facts
- The blackout began at about 12:33pm local time on 28 April 2025.
- The grid lost about 15 gigawatts of generation in quick succession.
- Most of continental Spain and Portugal, and briefly southern France, lost power.
- Investigators found no single equipment failure; the cause was insufficient voltage control margin.
What Happened
Just after midday on 28 April 2025, the interconnected grid serving Spain and Portugal lost about 15 gigawatts of generation in quick succession, more than half of what the two countries were supplying at that moment. The resulting voltage swings cascaded across the system, and within seconds most of continental Spain, Portugal and briefly parts of southern France lost power.
A panel of European grid experts, examining the event on behalf of ENTSO-E, found no single failed piece of equipment to blame. Instead they pointed to the grid running with too little of the reactive power reserve that keeps voltage stable, particularly in southern Spain, so that a chain of rising voltages tripped generators faster than operators could respond.
Power was restored within about a day, but the blackout renewed debate across Europe over how grids with a growing share of wind and solar keep the voltage stability that older fleets of large spinning generators used to provide for free.
Cause
Insufficient reactive power margin leading to a voltage instability cascade
Researched independently from public reporting, not from this site's own data. Source: ENTSO-E Expert Panel.