Notice aimed to create a working group to avoid problems
The Electric Red (REE) and the National Commission on Markets and Competition (CNMC) warned, in 2023, to the increasing risk of blackouts in the Spanish electrical system due to dangerous overvoltages ,. The warning that “urgent measures” were required of a resolution published in November 2023 in the State Official Bulletin (BOE), which was recognized that the levels of voltage in the transport network exceeded the normative limits and could lead to automatic disconnection of electric centers.
The scenario that culminated in the blackout on April 28, which left the Iberian Peninsula to the dark, was already identified in the technical reports. The CNMC document pointed out that Ree did not have enough tools to avoid these overvoltages and that the episodes of excessive tension had tripled between 2021 and 2023.
“The high tensions in the network could lead to the untimely shutdown of the network-related facilities,” read in the text of November 13, 2023, which added that voltage levels were “close or even above admissible values.”
The warning aimed to create a working group to avoid problems and should act mainly on two concrete areas: Galicia and Andalusia.
According to the newspaper, CNMC then validated a pilot project, which was renewed in early 2025 to collect more data and now continues its work.
The increase in renewable generation, which does not follow real -time voltage orders, and the reduction of synchronous generation – such as thermal or nuclear centrals – contributed to the imbalance in the network that led to blackout. The fall in industrial demand and the largest presence of small production units were also pointed out as critical factors.
On blackout, about 15 electric generation gigawatts – about 60% of the demand at that time – were abruptly turned off from the network.
Although the risks are identified, the measures recommended by the technicians have not yet been fully implemented. The Spanish government and Redeia, the holding of Ree, now admit a more cautious operation, with less weight from renewables and greater resource to combined gas cycles.
Investigations continue, without definitive conclusions in the short term.
