European Blackout Update (yes, it was solar)

“Could the reliability of the Iberian Peninsula grid be ensured by introducing new technical solutions? Technically, yes—but economically, the feasibility is more challenging.” ( – J.K. Nøland, below)

Jonas Kristiansen Nøland, associate professor at the Norwegian University of Science and Technology, has a verdict on the Iberian Peninsula blackout. His take follows:

Recent evidence indicates that Europe’s worst blackout, occurring in the Iberian Peninsula, originated from an unstable power grid. This instability likely triggered the cascading chain of events that followed.

In the half-hour leading up to the blackout, two episodes of power and frequency oscillations were observed in the Continental European synchronous area. Grid operators took actions to mitigate these oscillations.

The likely root cause of these undamped “inter-area oscillations” was the inherently low inertia of the Spanish power grid at midday, with approximately 70% of generation provided by inverter-based solar and wind. Such renewable sources lack the spinning reserve needed to effectively resist frequency oscillations.

Due to these unstable grid conditions, exceptionally high rates of change of frequency (RoCoF) occurred, which became the final nail in the coffin. As a result, low-frequency load shedding (UFLS) were not able kick in to save the day.

The critical tipping point came with the first generation loss at 12:32:57, involving roughly 2.2 GW, likely from solar PV generation in southwest Spain—a region dominated by solar power.

This generation loss, occurring under already unstable conditions (likely owing to overvoltages, which is the hypothesis of Luis Badesa) accelerated a rapid frequency collapse within the inertia-deficient system. Officials from Red Eléctrica (REE) noted a “strong oscillation” precisely at this point, leading to protective disconnections cascading across the grid due to high RoCoF.

Could the reliability of the Iberian Peninsula grid be ensured by introducing new technical solutions? Technically, yes—but economically, the feasibility is more challenging.

Notably, REE had already installed synchronous condensers and leveraged existing synchronous generation (nuclear, hydro, solar thermal) to bolster inertia and voltage stability. Unfortunately, these measures proved insufficient.

Nonetheless, deploying additional synchronous condensers or procuring fast frequency reserves (FFR) to provide virtual inertia through balancing markets significantly increases system costs.

Currently, FFR is typically procured only during short intervals of low inertia. Operating a consistently low-inertia grid would demand permanent, costly frequency support mechanisms, potentially making such a solution economically challenging.

Sources:
[1] ð„ðð“ð’ðŽ-ð„ ðžð±ð©ðžð«ð­ ð©ðšð§ðžð¥: https://lnkd.in/dajvNZ3f
[2] ðžð¥ð„ðœð¨ð§ð¨ð¦ð¢ð¬ð­ðš.ðžð¬ ðšð«ð­ð¢ðœð¥ðž: https://lnkd.in/dmRHp5Zz
[3] ð‘ðžð¬ðžðšð«ðœð¡ ð¨ð§ ð¢ð§ð­ðžð«-ðšð«ðžðš ð¨ð¬ðœð¢ð¥ð¥ðšð­ð¢ð¨ð§ð¬: https://lnkd.in/dCEVR549
[4] ð‘ðžð¬ðžðšð«ðœð¡ ð¨ð§ ð«ð¨ð­ðšð­ð¢ð¨ð§ðšð¥ ð¢ð§ðžð«ð­ð¢ðš ðŸð¨ð« ð ð«ð¢ð ð«ðžð¥ð¢ðšð›ð¢ð¥ð¢ð­ð²: https://lnkd.in/d8YXEumZ
[5] ð‘ðžð¬ðžðšð«ðœð¡ ð¨ð§ ð«ðžð§ðžð°ðšð›ð¥ðž-ð«ð¢ðœð¡ ð©ð¨ð°ðžð« ð ð«ð¢ðð¬: https://lnkd.in/ghMYqhsq

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Also see:

Inertia in One Lesson (Dave Edwards on LinkedIn) May 6, 2025

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Source: https://www.masterresource.org/electricity-blackouts/european-blackout-update-yes-it-was-solar/