Spain and Portugal power blackout: what could have caused it?

Spain and Portugal have gone dark. Late on Monday morning, an unprecedented power outage cut off electricity to millions of people across the Iberian Peninsula. Trains, phones, traffic lights, ATM machines and, well, anything hooked up to the national grid is now not functioning

Chaos reigns in these countries, which for the next few hours have effectively been tossed back to conditions last seen in the 19th century. Transport and commerce are out, and top government officials are in crisis as they try to get to the bottom of one of the worst power outages in European history. So, what could have caused this?

The simple answer is that right now, nobody knows for sure. One hypothesis points to a technical failure within the European electricity grid, which is highly interconnected across countries. Portugal’s grid operator, E-Redes, attributed the blackout to a “problem with the European electricity system,” suggesting a fault in very high-voltage lines that triggered a cascading failure across the Iberian Peninsula and parts of France.

🚨 BREAKING: MASS BLACKOUT is sweeping across Spain, hitting major cities like Madrid, Barcelona, Seville, Granada, and even Barajas Airport.

Portugal and parts of France are also going dank

A fire in southwestern France on the Alaric mountain that damaged a high-voltage power… pic.twitter.com/XuDcRzHBb9

— Cleiton Tortato (@cleitontortato) April 28, 2025

Another theory points to a fire on Alaric Mountain in southern France, which damaged a critical high-voltage line between Perpignan and eastern Narbonne, disconnecting the Iberian Peninsula from the broader European grid. This physical damage could have caused a sudden voltage collapse, as speculated in preliminary findings, leading to a rapid drop in power supply, with Spain’s grid losing over 10 gigawatts of demand in seconds.

Another potential cause is the region’s reliance on renewable energy sources, such as wind and solar, which can be unstable under certain conditions. Energy experts theorize that the Iberian Peninsula’s heavy dependence on these sources may have left them to sudden weather changes or mismatches in supply and demand.

The possibility of a cyberattack hasn’t been ruled out, with Spanish and Portuguese authorities actively investigating this angle. Spain’s National Institute for Cybersecurity and the Portuguese National Cybersecurity Center are examining whether a coordinated attack targeted the grid’s Supervisory Control and Data Acquisition (SCADA) systems.

Fingers are already being pointed in Russia’s direction, though no evidence currently supports this claim. The Portuguese Cybersecurity Center stated there was no indication of a cyberattack, but the Andalusian regional government president suggested it was the most likely cause, though we can only underline that nobody seems to know for sure.

Massive power cut in both Spain and Portugal because of a cyber attack. How long are we going to pretend Russia isn't waging a war against us? pic.twitter.com/B7D3cRUQ1G

— Glassmoist 🇸🇪🇺🇦 #Fella (@Dude18911) April 28, 2025

Lastly, human error or inadequate infrastructure maintenance could have played a role. The unprecedented scale of the outage, described as “exceptional and extraordinary” by Red Eléctrica’s operations director, suggests a rare convergence of factors. Aging infrastructure, combined with the complexity of managing an interconnected grid, may have amplified the impact of a single failure.

Either way, if you’re in Spain or Portugal right now, maybe it’s time to crack open a book and enjoy some peace and quiet until the juice comes back on. Then again, if you don’t have power, you probably can’t read this anyway.