The cause of the power outages across most of Portugal and Spain is still unknown, but a cyber attack has been tentatively ruled out by providers.

The electric network Red Eléctrica in Spain said in a press conference today that they couldn’t offer any answers about the issue.

However, the partially State- and privately-owned company said they were almost definitely ruling out an attack and believe the cause may be related to electricity supply from France.

The Spanish Prime Minister Pedro Sánchez has called for two investigations into the incident, one of which will be overseen by the EU.

Spain-based journalist Simon Hunter told The Hard Shoulder a suggested cause of extreme temperature swings from a Portuguese power company has since been walked back.

“It was picked up by Reuters, but then later in the day it was walked back and there doesn’t seem to be any suggestion,” he said

“So, we can rule out atmospheric conditions or any kind of weather event.

“I would suggest we can almost certainly rule out a cyber attack because, as cyber security experts have been explaining today, it would actually be incredibly difficult for a cyber attack of that scale.

“You have got different companies running different parts of the network, so for it all to go down like that at the same time due to a cyber attack is probably highly unlikely.”

General view of the interior of the Maria Zambrano train station the day after the widespread blackout. 29 April 2025 Alex Zea / Europa Press

In fact, Mr Hunter said that it seems two separate incidents happened “in a matter of seconds”.

“There’s two events, potentially related to the connection with France and then in the southwest with a solar power plant,” he said.

“It seems to be that because these two events coincided in time, that may have been what caused such a massive outage.

“But yeah, everyone is scratching their heads.”

Mr Hunter said yesterday was a “very, very strange day” for both countries.

Main image: Streets in darkness during the blackout in Barcelona, Catalonia (Spain). 29 April 2025 Alberto Paredes / Europa Press 04/29/2025 (Europa Press via AP)