The Day a Stork Took Down Half of Portugal’s Power Grid

How one unexpected event led to a new approach in system reliability for bird-related electrical flashovers

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The nationwide power outage that plunged Portugal into darkness on April 28, 2025, isn’t unprecedented, and neither is the lack of clear answers from authorities.

In Portugal, blackouts were common until the late 1970s. Throughout much of the Estado Novo dictatorship, the country was essentially an “energy island,” cut off from international power grids. It wasn’t until 1961 that Portugal’s electrical network was first connected to Spain, through a 220kV line linking Pocinho to Saucelle.

Afterward, in 2004, the creation of an electricity market brought new motivation to expand electricity interconnections with Spain, and with it a more reliable power grid, thanks to the added redundancies in the system, even if both countries remain disconnected from the rest of the European Union.

Since then, large-scale blackouts have been rare. Still, I remember nearly 25 years ago, half the country went dark for approximately two hours.

The stork blackout

The event was one of Portugal’s most unusual power outages. At 10 p.m. on May 9, 2000, the…