European Blackout Update (yes, it was solar) – Watts Up With That?

From MasterResource

By Robert Bradley Jr.

“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] 𝐄𝐍𝐓𝐒𝐎-𝐄 𝐞𝐱𝐩𝐞𝐫𝐭 𝐩𝐚𝐧𝐞𝐥: https://lnkd.in/dajvNZ3f
[2] 𝐞𝐥𝐄𝐜𝐨𝐧𝐨𝐦𝐢𝐬𝐭𝐚.𝐞𝐬 𝐚𝐫𝐭𝐢𝐜𝐥𝐞: https://lnkd.in/dmRHp5Zz
[3] 𝐑𝐞𝐬𝐞𝐚𝐫𝐜𝐡 𝐨𝐧 𝐢𝐧𝐭𝐞𝐫-𝐚𝐫𝐞𝐚 𝐨𝐬𝐜𝐢𝐥𝐥𝐚𝐭𝐢𝐨𝐧𝐬: https://lnkd.in/dCEVR549
[4] 𝐑𝐞𝐬𝐞𝐚𝐫𝐜𝐡 𝐨𝐧 𝐫𝐨𝐭𝐚𝐭𝐢𝐨𝐧𝐚𝐥 𝐢𝐧𝐞𝐫𝐭𝐢𝐚 𝐟𝐨𝐫 𝐠𝐫𝐢𝐝 𝐫𝐞𝐥𝐢𝐚𝐛𝐢𝐥𝐢𝐭𝐲: https://lnkd.in/d8YXEumZ
[5] 𝐑𝐞𝐬𝐞𝐚𝐫𝐜𝐡 𝐨𝐧 𝐫𝐞𝐧𝐞𝐰𝐚𝐛𝐥𝐞-𝐫𝐢𝐜𝐡 𝐩𝐨𝐰𝐞𝐫 𝐠𝐫𝐢𝐝𝐬: 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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