Reports indicate that 'overvoltage' refers to a situation where the voltage in the grid is excessively high, leading protective systems to shut down parts of the grid and causing widespread blackouts. On Tuesday, Spain's Minister for Ecological Transition, Sara Aagesen, stated in Madrid that on the day of the blackout, the voltage regulation capacity was insufficient. Theoretically, the Spanish grid should be stable enough to handle such situations.

Aagesen mentioned that overvoltage caused multiple power plants to shut down, leading to further outages. She criticized some energy companies for improperly disconnecting their plants from the grid 'to protect their facilities'. Moreover, she pointed out that the Spanish grid company REE also played a role in this issue, as its planning for generation was not careful enough, failing to include sufficient traditional power plants.

Compared to traditional turbine power plants, which are better at regulating grid overvoltage, REE failed to incorporate enough of them into the planning. Aagesen emphasized that there was no evidence suggesting this incident was a network attack. On April 28, a blackout occurred across Spain and Portugal, causing significant disruption to transportation and telecommunication systems. Southern France and Morocco were also briefly affected, marking one of the largest blackout events in Europe to date.