Overview

• The interim assessment details cascading overvoltages after pre-event oscillations and control-room actions that ultimately raised system voltage.
• Investigators did not identify the initial trigger and say some generation losses remain unexplained due to missing plant-level data and delayed third-party records.
• ENTSO-E reports no indication of a cyberattack and says neither renewable reliance nor limited interconnections contributed to the outage.
• Accountability remains disputed, with Redeia citing inadequate voltage support from some plants while utilities criticize the grid operator's planning and the panel's composition.
• Spain and Portugal continue to seek EU support for new cross-border links to strengthen system resilience to future disruptions.