The first official Spanish blackout report
It tries, but can't hide, that renewables were to blame.
In my two posts on the April 28th blackout in Spain, I foolishly promised to report back as the official reports came in. [Links to those posts are here and here].
On Tuesday, June 17, 2025 the first one did.
After wading through a 182-page PDF in dense Spanish, I’m beginning to regret that promise.
This is the report that was ordered the day of the blackout by Spanish prime minister Pedro Sánchez, to be conducted by Spain’s oddly-named Ministry for the Ecological Transition and Demographic Challenge (MITECO).
Aside: Here is a link to the press release about report (in Spanish). If you care, you can follow the links to the full thing.
In my second post, I made a slightly snarky suggestion that — since that same Ministry houses Spain’s meteorological bureau — we might get an official explanation that blamed the weather.
That was unfair. The Ministry’s report is real.
If redacted and incomplete.
The redactions are, to me, not surprising.
After a blackout, the blame game has dynamics every bit as powerful as those that overwhelmed the electric grid.
No company wants its name to appear in an official government report.
In the U.S. — as I said in my second post — NERC and ERCOT sometimes give grid equipment vendors witness-protection style anonymity, calling them ‘OEM 1’, ‘OEM 2’, and so on.
Incomplete, because the Ministry’s report doesn’t get to the initial cause.
The mysterious frequency oscillations — described in great detail in the report — were a symptom, not an explanation.
I suggested in my first piece, those were most likely induced by an interaction among DC-to-AC inverters, along the lines of what was found by ERCOT and NERC in the Odessa, Texas incident.
But enough of my theories.
Meanwhile, it’s good that we can lay some of the early speculation to rest.
There was, of course, no cyberattack. No forest fire took out the interconnector with France.
It’s also useful to have the official figures on Red Eléctrica’s generation mix at the time of the incident: 82% renewable, 10% nuclear, and 3% gas.
Red Eléctrica’s day-ahead mistake was to go ahead with fewer than 12 sources of synchronous generation.
Those, of course, give the grid inertia.
Red Eléctrica admitting this — according to the report — confirms what I call the ‘fragile grid’ hypothesis, which I outlined in my second post.
I’ve added ‘un origen multifactorial’ to my Spanish vocabulary deck.
One synchronous source had an excuse for being offline. It had notified Red Eléctrica in advance.
Others were being paid monthly stipends for grid-stabilizing services, but couldn’t deliver in time.
In Spain, there will be another round of blame game over that.
There were several factoids in the report that relate to solar surplus, a topic near to my dark heart.
The morning of the blackout, Spain was exporting its surplus solar to France, but at negative prices, meaning Spain was paying France to take it.
That was 1,000 MW, roughly the output of a large nuclear plant, such as Vogtle in Georgia.
Some 2,978 MW — almost three Vogtles — was being consumed by pumped-hydro to take advantage of the cheap surplus solar.
Just before the collapse, some wild things took place on interconnecters with France. At 12:33, 4609 MW was coming in from France on the AC lines while 802 MW was going out to France on HVDC line.
Then the interconnectors wisely, by the lights of their machine logic, decided to disconnect.
The Ministry’s report is not everything, but better than I expected.
So I’ll take it, for now.
There are a few nerdy details I’m still curious about.
At some point, someone suggested, based on the 12:30 time the blackout started, that it might somehow be related to the contract period for buying electricity in France.
If there’s anything to that, the report coming from ENTSO-E, the European Network of Transmission System Operators (TSOs), might get to it.
The details about the failings of the Spanish solar farms, for now, seem likely to stay in Spain.