Entso-E final report on Iberian 2025 blackout

I was supposed to fly home from Santiago de Compostella when the blackout happened. Me and my girlfriend had checked out of our hotel and headed to the bus stop to take the bus to the airport. The blackout had already started but we didn't realise (in hindsight, I do remember the pedestrian crossing not working. But I didn't think much of it). Anyways our flight was cancelled and it was clear we needed somewhere to stay the night.

I immediately rebooked the same hotel, but when we got back there the receptionist had left so you had to check in over the phone instead. Except WhatsApp wasn't working. Then mobile data went down. And before long we were walking through the old town going hostel to hostel looking for a place to sleep, as everything got darker and darker (due to the lack of powered street lighting). The old town in almost pitch black was pretty scary!

We ended up breaking back into the hotel, borrowing a bunch of towels from a laundry cart in the hallway and sleeping in this lockable room we found in the basement.

Besides that somewhat stressful part, it was a really strange but fun experience to see the city without power: no traffic lights, darkened shops with lots of phone lights, cafés still operating just with only outdoor seating and limited menus, the occasional loud generator, and most of all the people seemingly having a great time in spite of it.

I would've loved to have stayed out all night exploring the city, but finding somewhere to sleep that night was a bit more pressing!

I think people underestimate how valuable these reports are, so I’m very glad that detailed investigation is done here. Every major grid operator around the world is going to study this and make improvements to make sure this doesn’t happen on their grid.

In a lot of ways it’s like investigations into airplane crashes.

As someone who lived through the blackout it was wild. I felt back into the pre-internet, pre-smartphone era. It was pretty cool actually. The rumor mill spread so fast that Within hours the official word on the street was that we were getting hacked by a foreign military and people were joking that we had nothing of interest to be conquered xD

The fact that there is not a single root cause but several ones makes me instinctively think this is a good report, because it's not what the "bosses" (and even less politicians) like to hear.

If someone wants a "quick and dirty" answers - there's presentation linked https://eepublicdownloads.blob.core.windows.net/public-cdn-c...

page 11 contains "Full root cause tree" - one image with all the high level info

472 pages. That's going to be a nice bit of reading this weekend. It is very nice to see such a comprehensive report as well as the fact that it was made public immediately.

Can’t read all of this since it’s 424 pages but i want to point out that Australia is beating Europe on grid connected storage. Not on a per capita basis. It’s beating all of Europe combined outright https://www.visualcapitalist.com/top-20-countries-by-battery...

We did have many many problems previously. The state of South Australia went out for a couple of weeks at one point in similar cascading failures. This doesn’t happen anymore. In fact the price of electricity is falling and the grid is more stable now https://www.theguardian.com/australia-news/2026/mar/19/power...

This price drop is inline with the lowered usage of gas turbine peaker plants (isn’t that helpful right now? No need for blockaded gas for electricity).

A lot of people say it can’t be done. That you can’t have free power during the day (power is free on certain plans during daylight due to solar power inputs dropping wholesale prices to negative) and that you can’t build enough storage (still not there but the dent in gas turbine usage is clear).

It’s one of these cases where you’ve been lied to. Australia elected a government that listened to reports battery+solar is great for grid reliability and nuclear was always going to be more expensive.

That was quite the interesting read!

0.63 Hz and 0.2 Hz grid instability. Oh my.

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