As a nationwide blackout in Cuba stretched into a second day this past weekend, the stakes were rising for Jorge Pérez Álvarez.

The 21-year-old suffers from a genetic disease preventing his lungs from pumping air on their own. He needs a ventilator at all times to keep breathing.

His ventilator’s backup battery is supposed to last more than a day, but that has been tested repeatedly in recent weeks, including three nationwide outages that each pushed up against its limits. And with the power out for hours every day, there is hardly enough time to recharge it.

“I don’t know how long we can keep going,” said his mother, Xenia Álvarez, standing near her son’s crumpled body in his bedroom in a poor neighborhood of Havana. “His life depends on electricity.”

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