What Caused the Recent Power Outage in Spain, Portugal, and Southern France?

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when it happened i was sent some frequency captures from a friend and the frequency went far below any tolerances for dynamic stability of synchronous machines. I'm having trouble locating the picture now but I'll keep trying.

i have not kept with the latest, but I have heard more over time and it seems there were a couple generation loss events. first from tripping a transmission tie line and second from some IBR. the combination of generation loss into a system weakly coupled to main-land Europe created slow inter-area frequency oscillations. These are rarely seen in modern times because systems are usually strong and highly meshed/interconnected. but, when frequency begins to deviate, it traverses entire interconnections very quickly. it's fortunate the Iberian peninsula was the only thing to blackout and this should be seen a victory. It could have easily been far, far worse.

my personal opinion is, not knowing the official statement, that there's a difference in managing IBR generation and modeling generation portfolio costs with IBR and spain learned that difference. mismanagement of IBR (either in real-time or in planning or in commissioning stages (perhaps all three)) was ultimately to blame.
 
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I think the view is that small events occurred and there was insufficient stored energy in the system to cope with it, so more rotating machinery (or electronic equivalent ) will be required.
 
24. März 2026 23:43
Over the weekend, the European grid coordinator, ENTSO-e, released its final, detailed report on the event. While it’s largely consistent with the preliminary conclusions, the report provides much more detail about what went wrong and, more significantly, offers a clear picture of how the Iberian grid operators could make changes to prevent a similar event in the future.
...
What went wrong
The committee is clear that there was no single cause of the blackout (in fact, the report includes a “cause tree” encompassing 16 major events). But several issues stand out as obvious. First, a variety of generating facilities can also consume reactive power and could have helped keep the voltage within a tolerable range. But Spanish grid policy assigned fixed values to any renewable generating sources rather than allowing them to adapt to contingencies. As this was an early spring day, the majority of the power on the Spanish grid came from renewable sources, leaving the system with less flexibility.
Source:
https://arstechnica.com/science/202...iberian-blackout-policies-left-spain-at-risk/
 
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They will learn to use renewable energy better from it - and the lesson will NOT be to rely less on renewable energy.

More big batteries with grid forming inverters are going to add a grid stabilising buffer - given the pace of global uptake, probably significant amounts have been added already since that outage. Synchronous condensers are probably on the way out as big batteries do frequency regulating as an extra service at little additional cost. Confidence in them is growing.

I haven't heard of it being done but I expect wind and solar with modern inverters can also provide such buffering and frequency services, at the cost of running below maximum output, leaving some head room to both increase as well as decrease output on demand. Only when they are producing of course.

I also wonder if grids will shift from following the frequency of major generators to precise grid wide synchronisation - where even the output of spinning generators is channeled through inverters. ie decoupling the reference frequency from such generators.
 
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Ken Fabian said:
the lesson will NOT be to rely less on renewable energy.
Yup. It's that it'll cost more.
Even more.
Yet more still.

Not many countries (and: companies) are capable and willing to spend endlessly, especially when the growing prices also severely affecting competitive advantages on long run.

Something still can be an economical dead end (with a terrific backlash in store) even if it can be done.