As of January 20, 2026, Spain’s national markets and competition regulator implemented a new regulatory package aimed squarely at a growing challenge in the country’s mainland power system: abrupt voltage fluctuations.
The issue, linked to the rapid expansion of renewable generation operating under power factor control, prompted the regulator to convert a set of previously temporary measures into permanent regulation.
The approved amendments to operating procedures 3.1, 3.2 and 7.2 are designed to stabilize the electricity grid, reduce the need for real-time interventions and improve the system’s technical response to critical events. According to the official resolution, the measures were adopted after proving effective during a three-month temporary application period, between October 2025 and January 2026.
At the core of the problem is a fast-paced transformation of the power system. The regulator points to “abrupt changes in the output of plants operating under a fixed power factor,” meaning facilities where variations in active power simultaneously affect reactive power, directly impacting system voltage. The system operator notes that this behavior “had not occurred in the past at the current scale” and is driven by the surge in renewable installations, increased participation in real-time markets, and the emergence of negative electricity prices.
To mitigate stability risks, several key changes were introduced. Under procedure 3.1, the timelines of the Scheduling Process were adjusted to reduce redispatch and ensure that technical constraint solutions are fully resolved ahead of real time. The publication deadline for the Daily Base Operating Schedule (PDBF) was shortened from 30 to 15 minutes, while the window for market participants to submit nominations was reduced to 10 minutes.
In parallel, procedure 3.2, which governs technical constraints, now explicitly includes scheduling for insufficient upward reserve, bringing thermal generation units into the dispatch process at earlier stages. The goal is to lower the need for balancing energy and avoid last-minute corrections that could undermine system stability.
Regarding secondary regulation (procedure 7.2), the obligation to follow the Real-Time Schedule (PTR) has been extended to all scheduling periods, even when facilities are not actively providing frequency services. This change has sparked concern within the renewable sector, as “non-dispatchable technology providers will have to accept curtailments without direct compensation,” several stakeholders warned during the public consultation.
The consultation process included 23 submissions from companies and industry associations, revealing a mix of consensus and concern. While there is broad agreement on the need to safeguard voltage stability, market participants cautioned that “market operations should not be constrained nor deadlines shortened in ways that increase the risk of errors.” In this regard, the system operator’s decision to maintain the deadlines for submitting constraint-related bids was positively received.
One of the most sensitive issues remains the continuous obligation to follow the PTR for secondary regulation providers. Industry players are worried about the potential impact on aFRR service costs and the risk that some providers may exit the market.
Despite these concerns, the regulator argues that “these changes are necessary to anticipate events that could compromise the grid” and stresses that their impact will be assessed before they are fully consolidated. The measures complement other initiatives already underway, such as the gradual rollout of the new voltage control service under operating procedure 7.4, currently in its qualification phase. At the time of the resolution, only 35 out of 334 installations had passed the required tests to provide this service, although the qualification pace has accelerated in recent weeks.
The regulator emphasizes that the approved package is not final and “will be reviewed within a maximum period of one year.” Its evolution will depend on the outcome of an action plan to be developed by the system operator with industry participation. This plan is expected to address issues ranging from greater transparency on voltage variability to a potential review of whether compliance with control setpoints should remain voluntary.
The document makes clear that the future operation of Spain’s power system will depend largely on the ability of renewable technologies to adapt. In particular, a significant share of renewable plants will need to transition from a power-factor-based operating model to a more dynamic approach, incorporating programmed ramps and active voltage control.
For renewable energy developers and operators, these changes imply a reassessment of integration and operating strategies, especially in relation to ancillary services and balancing markets. While the new requirements pose operational challenges, they also open opportunities for those able to adapt quickly.
As the regulator itself notes, “the conditions of the electricity system have changed dramatically in just a few years,” making continued collaboration with market participants essential to ensure a secure and economically efficient grid operation.
Spain’s renewable sector is thus entering a new phase, where large-scale clean generation will require not only capacity growth, but also flexibility, control, and immediate technical response capabilities.
