Spain rules out cyber attack – but what could have caused power cut?

Passengers wait to board a train at Sants railway station in Barcelona on 29 April, 2025

The Spanish grid operator has ruled out a cyber attack as the cause of a massive power cut that crippled Spain, Portugal and parts of France on Monday.

Red Eléctrica’s operations director Eduardo Prieto said preliminary findings suggest “there was no kind of interference in the control systems” to imply an attack, echoing Portuguese Prime Minister Luís Montenegro the day before.

But the exact reason behind the cut is still unclear.

The grid operator said on Tuesday they “cannot draw conclusions” until they get concrete data. Spain’s Prime Minister Pedro Sánchez said investigators were trying to pinpoint the cause, and then would take all necessary measures “to ensure that this does not happen again.”

Information is trickling out about what happened at the time of the cut, leading to theories about what could have caused it. Experts told the BBC it was likely caused by several failures.

Here is what we know and what questions remain unanswered.