Red Eléctrica Rejects Maintenance Plans for Over 100 Spanish Plants

Red Eléctrica (REE), Spain's grid operator, has denied its approval to the maintenance plans of more than 100 power installations for the period between October 2026 and September 2027. Industry sources say this has never happened before.

The request covers nuclear plants, combined-cycle gas plants and pumped-storage stations. REE cannot force operators to comply, but it has formally expressed its disagreement with some of the proposed dates. Utilities must report their planned downtime to REE before the 15th of each month.

Why REE is worried

The operator says it must guarantee supply at a time of unusually high unavailability among combined-cycle plants. Since this summer, as much as 35% of their installed capacity has been out of service, meaning only 65% was available at times. REE also points to a large number of thermal plants declared unavailable for unplanned reasons, and denies it is imposing a blanket ban, noting that some maintenance periods were approved.

Since the 2025 blackout, REE has leaned more heavily on combined-cycle plants, which provide firm capacity and services such as dynamic voltage control. Their share of peninsular generation has risen from 8% to 19.4%.

That creates a vicious circle. Many of these plants are around 20 years old and were not designed for so many start-ups, so heavier use accelerates the need for maintenance that REE now wants to postpone.

Industry pushback

Sector sources criticise the timing: the refurbishments had previously been cleared and the necessary staff already hired, in a market where only Siemens, Mitsubishi and General Electric carry out this work. Since REE cannot compel them, the utilities have rejected the request to delay and are keeping their schedules. Some executives read the move as extreme caution, or as REE putting on record that it had warned about plant availability after the blackout.

The operator has also activated its active demand response service, which partially disconnects industrial consumers on a voluntary basis, a record eleven times this year, against none in 2025.

REE firmly rules out the risk of another blackout and says it is taking all necessary measures to keep supply stable. Still, the episode suggests the system's operating margin is narrow enough that routine maintenance has become a problem, and deferring overhauls may only push the difficulty into the future.