A Spanish government investigation attributes April's Iberian Peninsula blackout to cascading failures stemming from inadequate grid stability measures. Initial voltage fluctuations, exacerbated by insufficient reserve power plants and their poor response, triggered a self-reinforcing cycle. The report, released ahead of the full document, rules out a cyberattack and details a timeline of events leading to the widespread outage. The grid operator's unusually low number of on-call plants is highlighted as a critical factor.

Prepared by Jonathan Pierce and reviewed by editorial team.