A major blackout affected tens of millions of people across Spain and Portugal for up to 18 hours, with officials from both countries working to determine the cause. Despite extensive meetings, neither Spain nor Portugal has publicly speculated on the cause, although the possibility of a cyberattack has not been ruled out. The outage raised questions about the vulnerability of the countries' energy systems, particularly in light of their transition to renewable energy, though officials deny a connection. Investigations are underway with reports expected from Red Eléctrica, intelligence services, and the police, while the National Cryptologic Center reviews online systems. In Portugal, an abrupt voltage increase in Spain's electricity grid is suspected to have activated safety mechanisms leading to the blackout, and discussions are ongoing to prevent future occurrences.

The blackout, one of Europe's worst in decades, left millions across the Iberian Peninsula in darkness, affecting hospitals, trains, and supermarkets, with power restored by Tuesday morning thanks to connections with France and Morocco.

Spanish and Portuguese officials have not identified the cause of the outage, but investigations are ongoing, with a new committee established by Spain's Prime Minister Pedro Sánchez to ensure such an event does not recur.

There is speculation about whether Spain and Portugal's rapid transition to renewable energy may have increased their vulnerability to such incidents, though this connection has been officially denied by Spain.

A judge has mandated reports from Red Eléctrica, the intelligence service, and police within 10 days to explore the possibility of a cyberattack, and the National Cryptologic Center is reviewing online systems to rule out any hypotheses.

After power restoration, Spain's Interior Ministry adjusted alert levels, though Madrid and Extremadura remained at the highest alert level, reflecting ongoing concerns about the outage's implications.

Portuguese Prime Minister Luís Montenegro indicated the blackout might have been triggered by a sudden voltage spike in Spain's grid, which activated safety protocols, and he emphasized collaboration with Spanish authorities to develop better future responses.

The incident is anticipated to be a significant topic in upcoming political debates in Portugal, highlighting its importance in national discussions ahead of parliamentary elections.