4rd Champéry Power Conference, Champéry (Switzerland). 08-13 February 2026
Summary:
At 12:33 on 28th April 2025, a blackout occurred in the Iberian electricity system. Sixty million people lost the electricity supply. This is the first time in the history of the Spanish peninsular electricity system that a blackout has occurred. The most serious incidents in the peninsular system (July 1977, October 14, 1987, and August 24, 1994) never resulted in a blackout in the Iberian system. It is only comparable in continental Europe, in terms of severity, with the blackout of the Italian system on September 28, 2003. [...]
Spanish layman's summary:
Esta presentación resume la investigación llevada a cabo por un equipo dirigido por el autor a petición de Endesa e Iberdrola (las dos mayores empresas eléctricas españolas), en la que se examinan los hechos y circunstancias que provocaron el apagón en el sistema ibérico el 28 de abril de 2025. Aunque la investigación aborda todos los hechos y circunstancias que provocaron el apagón, esta presentación tiene como objetivo llamar la atención del público sobre nuevos análisis que ofrecen respuestas bien fundamentadas a cuestiones sin resolver derivadas de un estudio minucioso de los informes publicados.
English layman's summary:
This presentation summarizes the investigation conducted by a team led by the author at the request of Endesa and Iberdrola (the two largest Spanish electric utilities), examining the facts and circumstances that led to the blackout in the Iberian system on April 28, 2025. Although the investigation addresses all the facts and circumstances that led to the blackout, this presentation aims to bring to the audience's attention novel analyses that offer well-founded answers to unresolved questions arising from a careful study of the reports issued.
Keywords: Voltage collapse; Voltage control; Ancillary services
Publication date: 08-Feb-2026.
Citation:
L. Rouco, "The blackout of the Iberian Peninsula on April 28, 2025", presented at 4rd Champéry Power Conference, Champéry, Switzerland, 08-13 February 2026
IIT-26-012C_abstract
