Why did the lights go out in Spain and Portugal?

By Gabriel Gavin, Victor Jack, Aitor Hernández-Morales, Sam Clark, Max Griera | 04/29/2025 06:55 AM EDT

And what does it mean for Europe, its power grids and its electricity?

People wait outside a closed train station during a major power outage in Barcelona, Spain.

People wait outside a closed train station during a major power outage Monday in Barcelona. Emilio Morenatti/AP

A frantic search is on to figure out what, exactly, caused Spain and Portugal to lose power Monday, leaving millions of people without access to basic modern necessities.

The answer will have serious ramifications for the two countries — and for Europe as a whole.

The EU has been pressing the Iberian Peninsula, which has long operated as an energy island within the bloc, to link up better to Europe’s grids. Already on Monday, specialists were debating whether such connections could have helped prevent the massive blackouts — or put more countries at risk of experiencing spillover effects.

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There was also hand-wringing throughout the day about whether the outages were the work of cyber saboteurs launching a strike on Europe — even as no evidence emerged suggesting that was the case.

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