Investigations
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Inside the Control Room: Operator Decisions Before and During the Collapse
Before the April 2025 Iberian blackout, transmission-system operators were managing oscillations, cross-border power transfers and changing voltage conditions. This investigation examines their documented actions, the operational constraints they faced and the difficult interaction between oscillation damping and voltage control.
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The Final 90 Seconds: How the Iberian Grid Collapsed
The Iberian blackout unfolded in less than 90 seconds. ENTSO-E’s investigation documents a cascade of generation disconnections, rising transmission voltages, falling frequency and the eventual separation of Spain and Portugal from Continental Europe. This engineering reconstruction examines the sequence that brought down the grid.
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The Grid Before the Blackout: Generation, Topology and Voltage Control
Before the Iberian blackout of April 28, 2025, Spain’s transmission system was exporting electricity to neighboring networks while operators managed oscillations and changing voltage conditions. This engineering investigation examines the network configuration, generation resources, reactive-power capabilities and operating decisions that shaped the system’s vulnerability.
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Spain’s 2025 Blackout: How a Voltage Crisis Brought Down the Iberian Grid
On April 28, 2025, the electricity systems of mainland Spain and Portugal collapsed in a rapid cascade. Drawing on the ENTSO-E investigation, this engineering analysis examines the voltage-control failures, oscillations, generation disconnections and operational challenges behind one of Europe’s most consequential blackouts.