The cyberattack has been ruled out, voltage control failures have been detected, and urgent measures have been announced to strengthen the resilience of the national electrical system.
The Council of Ministers received the report from the Crisis Analysis Committee regarding the electrical crisis that affected the entire peninsula on April 28. The document, presented by the Vice President and Minister for Ecological Transition, Sara Aagesen, concludes that the massive blackout had a multifactorial origin, triggered by a problem of overvoltage with failures in the control and response of the electrical system.
The report was approved this morning by the National Security Council and represents the most thorough analysis conducted to date in Spain regarding an energy emergency of this nature. The government has announced that it will approve a package of measures next week to increase the robustness of the system, after analyzing over 300 GB of data, 770 information requests, and ruling out the hypothesis of a cyberattack.
A Chain of Technical Failures
The detailed chronology of the incident allows us to identify three critical phases:
- Phase 0: Days prior with growing voltage instability.
- Phase 1 (12:03 PM – 12:30 PM): The appearance of abnormal oscillations that caused voltage fluctuations and operator reactions that worsened the problem.
- Phase 2 (12:32 PM – 12:33 PM): A rapid increase in voltage and the progressive disconnection of plants across several provinces.
- Phase 3 (12:33 PM): Total collapse with loss of synchronization with France and zero electricity across the whole peninsula.
Restoration of supply began thanks to interconnections with France and Morocco and the restarting of autonomous hydroelectric plants, allowing 50% of demand to be restored by 10:00 PM and 99.95% by 7:00 AM the following day.
Main Causes Identified
The Committee identified three main causes:
Insufficient voltage control capacity: A historically low number of synchronous plants capable of stabilizing voltage were scheduled. Some did not respond adequately or even acted against directives.
Atypical oscillations: The first originated in the peninsula and necessitated changes to the network configuration, further complicating voltage control.
- Improper disconnection of plants: Several facilities disconnected without reaching the established thresholds, accelerating the collapse.
Additionally, it was found that some system protections, such as automatic load shedding, unintentionally contributed to the increase in overvoltage.
Key Recommendations
Among the measures proposed by the Committee are:
- Strengthening compliance supervision by all agents in the system.
- Improving voltage control capacity and response to oscillations.
- Implementing the PO 7.4 procedure to allow asynchronous installations to apply electronic solutions.
- Increasing flexible and industrial demand, enhancing storage capacity, and reviewing adjustment services.
- Boosting electrical interconnection with France and other neighboring countries as a strategic goal.
- In cybersecurity, it is proposed to accelerate the transposition of European regulations and implement measures such as network segmentation and event correlation systems.
Transparency and Consequences
The Committee expressed regret over access restrictions to information by some agents in the system and announced that it would report these cases to the CNMC for potential administrative procedures.
Sara Aagesen emphasized that this report "provides a clear roadmap to prevent similar incidents in the future" and highlighted the government’s commitment to act swiftly: "In just 49 days, we have compiled a rigorous analysis that will strengthen the Spanish electrical system."
The Council of Ministers will discuss and approve the first legislative and operational measures resulting from this report next week.