- All technical reports on the blackout published after the incident agree that it was not caused by a lack of inertia, but by problems in the grid’s voltage control mechanism.
- UNEF stresses that renewables are steadily reducing the cost of “ancillary services” used to control voltage—a service that was previously provided only by thermal technologies and that, since March 2026, renewables have also been able to provide thanks to the regulatory update of Operating Procedure 7.4, approved after the blackout.
- To accelerate the participation of photovoltaic plants in voltage control and further strengthen system security, UNEF recalls the need to ensure adequate remuneration for renewable companies providing this service.
- UNEF also highlights the importance of keeping regulations up to date for the safety of the electricity system: regulatory advances following the blackout have enabled renewables to control voltage and allowed storage to begin scaling up, but further progress is still needed on pending regulatory updates, such as “grid-forming,” so that renewables can also participate in inertia services, for which they are already technically capable.
Madrid, 27 April 2026. On the first anniversary of the blackout that occurred on 28 April 2025, the Spanish Photovoltaic Union (UNEF) emphasized that today, with the new regulation allowing renewables to participate in voltage control and with the progress of storage, the electricity system is safer and more stable than it was a year ago. However, it notes that further adjustments and pending regulatory updates remain, such as those related to “grid-forming,” which will enable renewables to provide inertia-related ancillary services to the grid, as they are already capable of doing.
According to all technical reports published after the incident—ENTSO-E, MITECO, REDEIA, Comillas University, and other international institutes—the blackout was not caused by a lack of inertia, but by problems in the grid’s voltage control mechanism. In this regard, UNEF points out that renewable energy sources, although fully capable of providing this service efficiently, accurately, and in a geographically distributed manner, were not allowed to do so at the time due to the outdated Operating Procedure 7.4.
UNEF positively assesses the regulatory progress made after the incident, such as the update of Operating Procedure 7.4, which now allows renewables to participate in voltage control. It calls for participation in this service to be extended not only to facilities connected to the transmission grid but also to those connected to the distribution grid. UNEF regrets that this regulatory update—requested for more than four years—only arrived after the incident and calls for institutional responsibility from all stakeholders to ensure that regulatory updates affecting the electricity system are implemented in a timely manner.
The association recalls that renewable energy can not only contribute to voltage control more effectively than thermal technologies—due to their geographic distribution and fast response capabilities—but can also effectively provide grid-forming functions and inertia services, both of which are key to system security. To achieve this, UNEF stresses the need to advance regulation on “grid-forming” so that renewable technologies can also provide these services. The deployment of this technology is currently pending the approval of technical implementation criteria by ENTSO-E.
UNEF also highlights the role of energy storage in ensuring system security and stability, as a fundamental tool for balancing generation and demand. In this regard, it welcomes the regulatory progress made in recent months, which is enabling its development, while also pointing out the need to address bottlenecks in current permitting processes due to insufficient human resources within the administration.
“The blackout showed that regulation cannot lag behind technology. If certain measures—such as allowing renewables to control voltage and establishing appropriate regulation for storage—had been approved when the sector requested them, the incident would likely have been avoided,” said José Donoso, Director General of UNEF.
A strategic opportunity for Spain
“The participation of renewable energy technologies in the electricity system is not only key to the proper functioning of the grid itself, but also to security of supply and our country’s energy independence, as they are domestic sources and also the most competitive way to generate energy in Spain,” Donoso added.
In the current international context, renewables have demonstrated their ability to reduce electricity prices, protect consumers from volatility in energy markets, and curb inflation driven by rising electricity costs.
“With the impact of the conflict in the Middle East, we are seeing how electricity prices in Spain have been between three and five times lower than in Germany and seven times lower than in Italy, thanks to renewables—especially during solar hours—protecting us,” Donoso emphasized.
Prices could be even lower thanks to renewables. In 2025, before renewables were allowed to participate in voltage control, the cost of technical constraints for voltage control reached €2.303 billion, of which €725 million corresponded to the additional cost of reinforced operation for voltage control. “With the participation of renewables in technical constraints for voltage control, more than 90% of this total cost could be reduced,” Donoso noted.
However, although 4.5 GW of renewables are already participating in voltage control—significantly reducing the cost of this service—this could rise to as much as 32.5 GW. The main barrier to accelerating these authorizations is the low remuneration currently offered to renewables for providing the service.
At present, renewables providing voltage control are paid €1/MVArh, compared to €100–€200/MVArh received by combined-cycle gas plants for the same service. This level of remuneration does not even cover the minimum investment required to provide the service, such as software upgrades, component recalibration, or the electricity needed to operate the equipment.
UNEF emphasizes that appropriate remuneration for renewables in voltage control services—still much lower than that received by combined-cycle plants—would boost the participation of more photovoltaic technology, which is the most efficient for this purpose due to its technical characteristics and location. This would improve system stability and reduce electricity prices for consumers by providing the service at a much lower cost.
A call for commitment from institutions and political parties
On this anniversary, UNEF calls on all political groups and institutions to recognize the fundamental role of renewables in system security, energy independence, and lowering electricity prices, and to commit to the regulatory updates and stability needed to unlock their full potential and protect this strategic industry.
“The energy transition protects us from uncertainty in international markets, both in terms of security of supply and by delivering low prices and system stability. But it also involves managing a more complex system with more stakeholders. To harness the full potential of renewables, we need to advance the electrification of homes and industries and ensure that regulation supports and leads this process with foresight and long-term commitment from all stakeholders,” Donoso concluded.