Finance
Spain's Watchdog Probes Major Energy Companies Over Historic Blackout
Published by Global Banking & Finance Review®
Posted on April 17, 2026
3 min readLast updated: April 17, 2026
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Spain’s CNMC has launched formal investigations into Red Eléctrica (Re deia) and major energy firms—Endesa, Iberdrola, Naturgy, Repsol, and several power plants—for potential breaches related to last year’s April 28, 2025 blackout, citing prolonged rule violations though not attributing blame.
Spain's watchdog probes major energy companies over historic blackout
By Pietro Lombardi and Marta Serafinko
Regulatory Investigation into the 2025 Blackout
Overview of the Watchdog's Actions
April 17 (Reuters) - Spain's energy and competition regulator said on Friday it had opened formal probes into the country's largest energy companies and the power grid operator over last year's unprecedented blackout in Spain and Portugal, after finding evidence that some power sector rules were breached over extended periods.
The watchdog opened probes into grid operator Red Electrica - a unit of Redeia - as well as energy companies Iberdrola, Naturgy, Endesa and Repsol. It also said it was investigating individual power plants.
Details of the Investigations
The information available for each proceedings is limited. Red Electrica is being investigated for "very serious infringements", according to the watchdog's website, while the others for "serious infringements".
Potential Penalties and Company Responses
CNMC head Cani Fernandez has previously said that the most serious breaches could lead to fine of up to 60 million euros ($70.80 million).
Iberdrola, Endesa and Naturgy declined to comment. The other named companies did not immediately reply to requests for comment.
Background and Impact of the Blackout
A number of investigations have analysed the causes of the massive outage, which plunged large parts of Spain and Portugal into darkness for up to 16 hours on April 28, 2025. Most focused on identifying the causes, without assigning blame.
Findings and Ongoing Proceedings
The National Commission on Markets and Competition, or CNMC, said that while the violations did not cause the blackout, they may have affected power system operations and could amount to administrative infringements, requiring a formal investigation.
The names of the companies being probed were disclosed on the watchdog's website after the market close.
Recommendations and Further Steps
In a report last month, the CNMC recommended measures to mitigate voltage swings in the power grid following the blackout, as well as boosting French power links. It did not assign blame, saying it was examining potential breaches separately.
On Friday, the CNMC said it found a chain of events that progressively destabilised the power system and culminated in the April 28, 2025 outage, whose immediate cause was a surge in voltage.
It added that some suspected breaches had persisted for long periods, but said this did not amount to assigning responsibility for the origin of the blackout to the companies involved.
Next Steps in the Investigation
The proceedings can last between nine and 18 months, depending on the seriousness of any infringement, and affected parties will be able to submit arguments and evidence.
($1 = 0.8475 euros)
(Reporting by Marta Serafinko and Pietro Lombardi. Editing by David Latona, Mark Potter and Louise Heavens)
Key Takeaways
- •Spain’s energy watchdog CNMC has initiated approximately 20 sanction proceedings against the grid operator and generation firms for suspected prolonged electrical sector regulation violations (elpais.com).
- •While the infractions didn’t cause the blackout, they may have affected system stability, prompting formal investigation procedures lasting 9–18 months (huffingtonpost.es).
- •Last year’s unprecedented April 28 outage was triggered by a sudden voltage surge that led to cascading failures, and investigations (including one by Entso‑E) stress multifactorial causes and grid resilience issues (apnews.com).
References
Frequently Asked Questions about Spain's watchdog probes major energy companies over historic blackout
1Which companies are being investigated for the 2025 Spain blackout?
The CNMC is probing Red Electrica, Iberdrola, Naturgy, Endesa, and Repsol over the 2025 blackout.
2What prompted the Spanish watchdog to launch these probes?
The CNMC found evidence that power sector rules were breached over extended periods before the 2025 blackout.
3Did the suspected breaches cause the blackout?
According to the CNMC, the suspected breaches did not cause the blackout, but may have affected power system operations.
4How long could the investigation proceedings last?
The proceedings can last between nine and eighteen months, depending on the seriousness of any infringement.
5What was the immediate cause of the blackout on April 28, 2025?
A surge in voltage, following a chain of destabilizing events, caused the historic blackout.
