The Iberian Peninsula’s widespread blackout raises questions about the resilience of the electric power infrastructure in the two countries — and to an extent, the rest of Europe.

Spain’s power company, Red Eléctrica, proudly declared on April 16 that enough renewable energy had been generated to cover demand. “The ecological transition is moving forward,” it said.

Less than two weeks later, Spain and Portugal experienced an 18-hour blackout that disrupted daily life, shutting down businesses and schools and crippling trains and mobile networks.

Officials have given few details on the cause of the outage. But the incident exposed how Spain and Portugal, promoted as success stories in Europe’s renewable energy transition, are also uniquely vulnerable to outages, given their relative isolation from the rest of the continent’s energy supply.

“This disruption serves as a clear warning,” wrote Pratheeksha Ramdas, an analyst at Rystad Energy, a consulting firm. “Future grid failures could have even more

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