The information is outlined in the factual report released today by the expert panel of the European Network of Transmission System Operators for Electricity (ENTSO-E), which serves as a preliminary technical assessment of the incident.
The final document will include a detailed analysis of the root causes and recommendations to strengthen the resilience of the European electrical system.
The report presented today confirms that the blackout was triggered by a series of sudden disconnections of renewable production, mainly solar and wind, in various regions of Spain, which removed more than 2.5 gigawatts of capacity from the grid in less than a minute. The loss of these generators reduced the available reactive compensation, causing a sharp increase in voltage and leading to the collapse of the Iberian system.
At 12:33 PM (Brussels time), Portugal and Spain lost synchronism with the continental grid, and automatic defense plans failed to stop the cascade of failures. Shortly thereafter, interconnections with France and Morocco were disconnected, isolating the Iberian Peninsula and culminating in the total failure of national electrical systems.
The restoration of the network began immediately, with emergency starts and support from interconnections. Portugal managed to restore the transmission system at 12:22 AM on April 29, and Spain completed the process around 4:00 AM the same morning.
