La National Commission of Markets and Competition (CNMC) The regulator has set its sights on Iberdrola by opening a sanctioning procedure classified as "very serious" related to the activity of its nuclear power plant in the context of the major blackout of April 28, 2025. A year after that power outage that left a large part of the Iberian Peninsula without electricity, the regulator is intensifying its offensive on the behavior of the big electricity companies.
This new procedure affects Iberdrola Spain and Iberdrola Nuclear Generation This investigation is part of a wave of inquiries that the CNMC has announced in recent weeks. While the opening of the case does not, in itself, determine that Iberdrola caused the blackout, it does indicate the existence of serious evidence of possible regulatory breaches that could result in multimillion-euro fines.
A "very serious" case concerning the blackout of April 28, 2025
The regulator has initiated this investigation due to an alleged very serious offense related to zero electricity registered April 28 of 2025. The investigation focuses on the performance of the Cofrentes nuclear power plant, which is 100% owned by Iberdrola, during the blackout day and in other previous periods analyzed by the CNMC.
The formal date of initiation of the proceedings appears in the CNMC records on April 23This comes right at the end of the first anniversary of the major blackout. From that moment, the official processing period for the procedure begins, within a timeframe that can be extended, depending on the severity, up to a maximum of eighteen months.
In these types of processes, Iberdrola and the other parties involved have the possibility of to submit allegations, provide documentation and propose evidenceDuring this phase, the CNMC must determine whether the initial indications have become proven infringements or whether, on the contrary, the case should be archived in whole or in part.
Cofrentes, at the center of the regulatory spotlight
The new procedure places the Cofrentes nuclear power plant In the eye of the regulatory storm. The plant, located in the Valencian Community and operated entirely by Iberdrola, is cited in several official texts and communications as one of the facilities whose behavior has been scrutinized in the investigation of the blackout.
According to the evidence gathered by the CNMC, the case revolves around the possible unjustified reduction in production or supply There have already been problems with the plant's availability during critical times for the electrical system. Some accounts suggest that Cofrentes's inactivity was due to economic reasons, citing a lack of profitability for entering service, a point that the regulator will now have to analyze in detail.
The opening of this investigation adds to other proceedings that, taken together, have significantly increased the pressure on Iberdrola. The company, which has long defended the continuity of the nuclear park As a key element for security of supply, it thus faces a scenario in which the management of these plants is scrutinized down to the millimeter.
The Cofrentes case is particularly relevant because Iberdrola has a stake in six of the seven nuclear power plants operating in Spain and holds the total control of this plantWhat happens with this case could set a precedent on how business decisions to halt or reduce production are assessed, from a sanctioning point of view, in a context of systemic strain.
Almaraz and the cascade of very serious cases
The investigation into Cofrentes is not the only one. Just a few days earlier, the CNMC had already announced the opening of another investigation. very serious case against the Almaraz nuclear power plant, managed by the company Centrales Nucleares Almaraz-Trillo, in which Iberdrola is the main shareholder and shares ownership with Endesa and Naturgy.
In the case of Almaraz, the regulator is also investigating a possible non-compliance with the same article 64.37 of the Electricity Sector Law. Evidence of unauthorized reductions in production or supply capacity and repeated failures to meet facility availability obligations during the blackout period are being analyzed.
The CNMC has indicated that, on the day of the blackout, part of Spain's nuclear power plants were unavailable for various reasons. In the vicinity of Almaraz and Trillo, situations such as the following were mentioned: unavailability due to refueling in one of the reactors and the non-operation of another unit for economic reasons. These types of decisions, if they do not comply with regulations, can be considered very serious.
With the addition of Cofrentes and Almaraz to the list of cases classified as very serious, Iberdrola now has several procedures of the utmost severity in the investigation opened by the CNMC. Added to this is the very serious case initiated against Spanish Electrical Network (REE), responsible for the operation of the system, for alleged deficiencies in the scheduling of the generation mix.
Meanwhile, the file on the association that owns Almaraz and Trillo The Cofrentes case is being processed in parallel with dozens of investigations classified as serious, reflecting the unprecedented scope of the sanctions offensive linked to the blackout.
More than fifty proceedings in the electricity sector
The case of Iberdrola's nuclear plant is part of a extensive battery of sanctioning proceedings which the CNMC has been detailing since mid-April. In total, the regulator has compiled around 56 files related to the blackout of April 28, 2025, and other disturbances detected in the electrical system in the previous two years.
Of those procedures, only a small group—including those affecting— Cofrentes, Almaraz and the Electric Network– are categorized as “very serious”. The rest are classified as “serious” and are directed against both large electricity companies and owners of combined cycle power plants, renewable energy facilities and hydroelectric infrastructure spread throughout the country.
The CNMC has divided the focus mainly between Iberdrola and EndesaThe two largest electricity companies by number of customers and network reach. Iberdrola is, by far, the company with the most open proceedings: nearly twenty cases have been initiated against it, several of them directly linked to its nuclear business. Endesa, for its part, has accumulated more than a dozen.
Alongside these two great ones, there are also Naturgy, Repsol, TotalEnergies, Engie, ContourGlobal and other companies that own specific power plants, in addition to the Ascó-Vandellós II Nuclear Association and Bahía de Bizkaia Electricidad, among others. Each case is linked to different aspects: from the availability of the plants to the submission of bids considered disproportionate in the electricity market.
The regulator insists that this set of files is intended to purge administrative responsibilities Regarding the system's operation, this does not, in itself, point to a single company as responsible for the blackout. The official investigation has already indicated a multifactorial origin for the incident, in which several failures and technical circumstances converged.
Legal framework, deadlines and possible sanctions
The legal heart of the very serious case against Iberdrola's nuclear plant lies in the Article 64.37 of Law 24/2013 of the Electricity SectorThis precept penalizes the unjustified reduction of production or supply, as well as the repeated non-compliance with the availability obligations of generation facilities, due to the impact it may have on security of supply.
While offenses classified as "serious" are usually related to failures in the maintenance or operation of the facilities "Very serious" offenses are reserved for conduct that may cause significant harm to the functioning of the market or the security of the electricity supply, even if there is no immediate risk to the system.
In terms of economic sanctions, the law stipulates that fines for very serious offenses The fines can reach up to 60 million euros, depending on the specific severity of the offenses, the profit obtained, and the turnover of the sanctioned company. In cases considered serious, the maximum fine is 6 million euros.
The open files have a maximum processing time of between nine and eighteen monthsDepending on the classification of the infringement. Within this period, the CNMC must complete its investigation, gather and assess evidence, hear the arguments of the companies involved and, finally, issue a resolution that confirms, modifies or dismisses the initial accusations.
Even so, the regulator itself has emphasized on several occasions that The initiation of a case does not prejudge the final outcomeIn other words, the opening of the procedure does not equate to a conviction or an automatic sanction, but rather to the formal start of a detailed analysis of whether or not sanctionable irregularities have occurred.
This entire process unfolds in a context where the behavior of nuclear power plants, and especially those in which Iberdrola has a stake, is being scrutinized precisely when the sector is debating the extension of the useful life of some plants and the schedule for closing the Spanish nuclear park.
Impact on Iberdrola and on the debate about nuclear energy
For Iberdrola, the very serious sanctioning proceedings against its nuclear plant come at a delicate moment from both a reputational and regulatory standpoint. The company, which presents itself as one of the strong advocates of maintaining nuclear power generation As a backup to the electrical system, it now faces the uncomfortable task of justifying to the CNMC the behavior of its facilities on critical days such as the great blackout.
The fact that Cofrentes and Almaraz are among the entities being investigated for alleged unauthorized production reductions or for failing to meet availability obligations fuels the debate about How nuclear power plants are managed economically in Spain. Some of the regulator's investigations suggest that certain plants may have chosen not to operate, citing economic losses if they came online at certain times.
At the same time, the barrage of cases comes as owners of facilities such as Almaraz negotiates the extension of the life of its reactors beyond the initially planned dates. These decisions are pending technical reports from the Nuclear Safety Council (CSN) and the subsequent position of the Government, in a scenario where public opinion is closely monitoring any sign of a lack of rigor in the management of these facilities.
For the sector as a whole, the CNMC's actions represent a clear warning that strict compliance with availability and operation obligations It is a regulatory priority. The message is that business decisions linked to the profitability of power plants cannot compromise security of supply or unduly disrupt the functioning of the electricity market.
In this context, the very serious case against Iberdrola's nuclear plant has become one of the key files in the great blackout caseThis is due both to the importance of the affected company and to the central role of nuclear energy in the Spanish and European electricity mix.
With all these elements on the table – the seriousness of the accusations, the potential impact of the sanctions, the importance of Cofrentes and Almaraz in the nuclear fleet, and the open timeline for closing or extending the life of the plants – the outcome of this case will be key to understanding how the Spanish electricity sector is adapting to a more demanding regulatory environment and reinforced CNMC oversight of Iberdrola's nuclear power plants.
