Authored by John Walter via Substack,
At 12:33 on the afternoon of 28 April 2025, mainland Spain and Portugal lost their electricity supply. Red Eléctrica de España, the Spanish transmission operator, logged the loss of about fifteen gigawatts of generation - close to sixty per cent of Spanish demand at that moment - within seconds. Supply was interrupted for roughly ten hours across most of the peninsula and longer in some districts, affecting an estimated sixty million people. Trains stopped between stations, payment terminals froze, mobile service thinned as tower batteries drained, and water pressure sagged in elevated neighbourhoods.
The final report from ENTSO-E, the European network of transmission operators, published on 20 March 2026, attributed the event to a combination of technical factors and successive generation disconnections rather than to a single fault. Nothing had attacked the Iberian grid, which is part of why the afternoon deserves to be remembered. Every serious rehearsal the industry runs assumes something worse.
Since then the system has not become more forgiving. On 4 May 2026, the North American Electric Reliability Corporation issued a Level 3 "Essential Actions" alert, its highest severity, after a run of incidents in which a thousand megawatts or more of computing load dropped off the bulk power system without warning. NERC's State of Reliability for 2026 recorded conventional forced-outage rates climbing to 9.2 per cent, and documented one event in whi
