Causes of the Gran Apagón (Spain), first oficial report

<https://www.theguardian.com/world/2025/jun/17/expert-report-rules-out-cyber-attack-for-spain-and-portugal-april-blackout>
     *Spanish minister rules out cyber-attack as cause of April blackout, after expert report*
     System failure caused by network’s inability to control grid voltage said to be behind outage in Spain and Portugal
     The unprecedented blackout that brought the Iberian peninsula to a standstill at the end of April was caused by surging voltages triggering “a chain reaction of disconnections” that shut down the power network, an expert report commissioned by the Spanish government has found.
     Speaking to reporters on Tuesday afternoon, the country’s environment minister, Sara Aagesen, ruled out a cyber-attack as the cause of the outage on 28 April, saying it had been down to a “multifactorial” system failure caused by the network’s inability to control grid voltage.
     (read the rest on the link if desired, it is in English)
<https://www.bbc.com/news/articles/c62d8k8edgxo>
     *Spain's government blames huge blackout on grid regulator and private firms*
     3 hours ago
     Guy Hedgecoe
     BBC News in Madrid
     The Spanish government has said that the national grid operator and private power generation companies were to blame for an energy blackout that caused widespread chaos in Spain and Portugal earlier this year.
     ...
     Nearly two months after the unprecedented outage, the minister for ecological transition, Sara Aagesen, has presented a report on its causes.
     She said the partly state-owned grid operator, Red Eléctrica, had miscalculated the power capacity needs for that day, explaining that the "system did not have enough dynamic voltage capacity".
     The regulator should have switched on another thermal plant, she said, but "they made their calculations and decided that it was not necessary".
     Aagesen also blamed private generators for failing to regulate the grid's voltage shortly before the blackout happened.
     "Generation firms which were supposed to control voltage and which, in addition, were paid to do just that did not absorb all the voltage they were supposed to when tension was high," she said, without naming any of the companies responsible.
     (read the rest on the link if desired, it is in English)
<https://www.eldiario.es/economia/informe-apagon-detecta-centrales-no-estaban-regulando-tension-desconexion-indebida-instalaciones_1_12391582.html>
Translated article (by DeepL)
     *The blackout report detects power plants that ‘were not regulating voltage’ and an ‘undue’ disconnection of installations.*
         The historic energy blackout was due to ‘a combination of factors’: there were plants “available” to regulate voltage that were not doing so ‘according to the regulations’ and there were plants that were disconnected ‘improperly’, according to Aagesen
      - The government gives an ultimatum to the electricity sector due to its delays in providing data on the blackout.
     Antonio M. Vélez
      17 June 2025 13:58 h Updated 17/06/2025 17:02 h
     14-18 minutes
     A phenomenon of ‘overvoltages’ and a ‘chain reaction’ caused by ‘a combination of factors’ of several agents in the sector, with a plant that is not available and Red Eléctrica (REE) does not decide to replace it; generation plants that ‘were not regulating voltage’ as required by the regulations and an ‘improper’ disconnection of facilities. These are the causes of the historic blackout on 28 April, as explained this Tuesday by the Third Vice-President and Minister for Ecological Transition, Sara Aagesen.
     At a press conference after presenting the report drawn up by the committee investigating the very serious energy blackout, approved this morning by the National Security Council, Aagesen explained that one of the causes of the blackout is that the system ‘did not have sufficient voltage control capacity’.
     The thermal generation groups that had to do so, ‘many of them’ paid financially, ‘did not contribute’ to doing so because the plants ‘were not programmed’ properly. It should be remembered that for at least five years the National Commission for Markets and Competition (CNMC) has been planning to approve a regulation to regulate this issue. The current one is ‘obsolete’, as the regulator itself has acknowledged.
      Aagesen insisted that ‘there are several causes’ of the blackout. One of them is ‘poor voltage regulation capacity’, due to ‘poor planning’ or because ‘some operators’ were not complying with the regulations.
     The result of this deficient voltage control is that this parameter ‘did not stop rising’ that morning and the disconnections of plants began. Also the ‘smaller’ ones, which the system operator, REE, ‘cannot see because they are in the distribution network’. After a first disconnection in Granada and those already known in Badajoz and Seville, there are more disconnections that had not been revealed until now in Segovia, Huelva and Cáceres.
     According to Aagesen, ‘some of these disconnections occurred improperly’, i.e. before reaching the overvoltage levels allowed by the regulations, and other disconnections occurred ‘within the authorised limits to protect the installations’. And from there to a massive ‘blackout’ within five seconds, with a ‘chain reaction’ against which there was ‘nothing to be done’.
     In the first phase of voltage instability, on the eve of the blackout, REE asked 10 power plants ‘spread throughout the territory’ that were not matched by the market to enter the so-called system of technical restrictions in order to control the voltage. But that Sunday afternoon, one of the planned plants was declared ‘unavailable’.
     Faced with this change, the system operator has to ‘readjust’ and decides to ‘reschedule but not replace’ that plant: it only does so at dawn. The report does not identify this plant because it is ‘anonymised’ at the express request of the companies, according to sources from Transición Ecológica.
     The Vice-President called for ‘reflection’ by ‘all the agents’ in the electricity system but did not want to point out responsibilities, which is something that will occur in ‘the next phase’: it will be ‘the administrative and judicial procedures’ that will have to establish them, in reference to the decisions that the CNMC may take and the proceedings that are already underway in the National Court.
     On the day of the blackout, from 10.30 a.m. onwards, voltage instability intensified, although ‘within the limits’ set by the regulations, with various calls from the control centres. At 12:03 a.m. an ‘atypical’ oscillation arrived, with a higher than normal frequency.
     The system operator links it to ‘a specific installation and its anomalous behaviour’; it takes “effective” measures to dampen it but the ‘meshing of the grids’ and the low demand contribute to ‘an increase in voltage’; it also reduces the export of energy to France, which means that generation in Spain falls and voltage rises.
     At 12.16 this oscillation reappears and ‘dampens again’. Another oscillation occurs at 12.19 which is absorbed and the result is a negative effect ‘on system voltage’. It is decided to connect a power plant in the southern zone but it will take ‘an hour and a half’ to connect. And the disconnections of plants begin.
     Aagesen announced that the next Council of Ministers will approve a Royal Decree-Law with a package of measures to ensure that the incident ‘does not happen again’. It will ‘accelerate the implementation’ of the National Energy Commission (CNE) announced more than a year ago; the ‘supervision and verification’ of system agents will be strengthened, storage will be promoted and the CNMC will approve these regulations to allow renewables to control voltage, as requested by REE in 2021.
     Aagesen explained that in the analysis of the operation of the system, more than 100 requests for information were made, with more than 700 requests and millions of data in 170 GB of information.
     The report includes a first phase of voltage instabilities, also in the ‘days prior’ to the blackout, a second phase of system oscillations (in the half hour prior to the outage), another of generation losses, and the subsequent collapse of the electricity system. A ‘complex, delicate’ analysis with “contradictory” data and ‘information that in the end has not arrived’. These ‘omissions’ have been ‘made explicit in the report’ that will be published this afternoon.
     From the point of view of cybersecurity, it has been concluded that ‘there is no evidence of cyber-incident or cyber-attack as a cause of the energy crisis, neither in the operator nor at the different levels’.
     However, ‘vulnerabilities’ and ‘shortcomings’ have been identified in the systems in the face of potential risks that will be “exploited” to issue recommendations for the future, following ‘the largest investigation into cybersecurity that has ever taken place in our country’, with more than 1600 hours of work, more than a thousand IP, more than 133 GB and fourteen operators analysed: from the system operator to the more than 30 control centres of the distributors throughout the country; and a third level ‘of detail’ of the generation facilities.
     Some conclusions will be brought to the attention of the CNMC: those issues that should be brought to the CNMC's attention. The report, due to a ‘confidentiality obligation’ has “anonymised” information, ‘on most occasions’ at the request of the actors involved. Aagesen is due to appear before the Official Secrets Committee this week.
     The report has been presented 49 days after the blackout, ‘practically half the time Europe gives to present its report to the EU’ and much earlier than expected.
     Aagesen had promised that the document would be ready within three months of the incident, but in recent days (in parallel to the explosion of the scandal of alleged corruption of Santos Cerdán, now ex-Secretary of Organisation of the PSOE) the meetings of the inter-ministerial committee investigating the outage have accelerated. The last meetings were held last Friday, Sunday and Monday.
     In total, this body chaired by Aagesen and made up of ‘state professionals of recognised prestige’ was created on 30 April. It is made up of several ministries and has held 14 meetings since this historic Iberian zero, which has provoked cross accusations between the electricity companies (particularly Iberdrola) and the system operator, against the backdrop of the multi-million dollar compensation at stake.
     On 4 June, the committee went so far as to write to the electricity companies to express its ‘concern’ about the slowness in sending certain information, which led aelec, which includes Iberdrola and Endesa, to state that it is ‘absolutely false’ that they were ‘hiding information’ about the blackout, although these two companies acknowledged that they had some requests for data pending to be answered.
     The committee is made up of several ministries, in addition to Ecological Transition (Economy, Defence, Interior...) and organisations such as the National Cryptologic Centre and the Defence Staff. The Nuclear Safety Council (CSN) and the CNMC, which will also draw up its own report, will be ‘invited’. In addition to this document, as required by EU regulations, the European transmission operators' association ENTSO-e, of which REE is a member, will draw up its own report.
     Translated with DeepL.com (free version)
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Cheers, Carlos.