I’ll just link previous threads on the subject:

Did solar power cause Spain’s blackout?
Renewable energy is changing the grid. How can we keep it reliable?
I’ll just link previous threads on the subject:
I’m pretty sure none of the interconnects operate at 120V, more like 750KV.
A friend who lives in Moratinos, Palencia, Spain says the power has been off and on today.
That can be tough for people who are dependent on electricity, so 99 percent. There’s empathy for sure!
Meh. It took that long to start the power in Aus.SA, but that’s because the black-start generator failed, because it hadn’t been in use, because other energy sources were subsidized.
As we can see, it didn’t take that long to get Spain and Portugal started again.
I was a bit surprised that ‘black start’ was required, given that a region of Spain powered up from France, and the availability of Wind power, but I’ve read they did start with gas-fired generation before powering up the nuclear and coal.
Yeah, an extended power outage during one of the worst winter storms in recent history that killed upwards of 250 people and caused 200 billion in damage will do that.
And as was to be expected, it gets political before you know it. Some claim (or just hint at the possibility) that renewables were at fault for the blackout:
Renewable energy is changing the grid. How can we keep it reliable?
While in Spain itself the debate circles around nuclear plants (among educated people, at least), whether they were a help or did not have any influence, whether they should kept running after 2027 (when the left leaning governement plans to shut them down) or not.
Russia, on the other hand, claims that the blackout was a consequence of the sanctions imposed against Russia:
Una campaña desinformativa rusa falsificó contenidos de The Independent y de France 24 para difundir desinformación sobre el apagón, buscando viralizarlo en redes como Twitter (ahora X)
while fake news of uncertain origin claim falsely the the President of the Europen Commission, Ursula von der Leyen, has accused Russia of being the cause of the blackout:
Ursula von der Leyen no ha dicho que el origen del apagón sea un ataque ruso
She has not said that and it probably is not true either.
Just a little sample of some after shocks.
Some more info - not due to any power plan failure, but poor grid management:
The report concludes that several steps meant to address a small instability made matters worse, eventually leading to a self-reinforcing cascade where high voltages caused power plants to drop off the grid, thereby increasing the voltage further
(this is mentioned in one of the comments)
In response to this new oscillation, and in accordance with the protocols already activated at 12:03 h, the following measures were implemented:
• Coupling of 400 kV transmission lines to reduce system impedance.
• Reduction of export exchange with France to 1,000 MW (with the HVDC link set to 1,000 MW from Spain to France, resulting in zero net export via AC lines). This represents a total reduction of 1,300 MW.
• Reduction of export exchange with Portugal from 2,545 MW to 2,000 MW, a decrease of 545 MW.These three measures contributed to increase the system voltage. The first having an immediate impact, while the two reductions in power exchange progressively raise voltage levels as the dispatch schedules are up-dated.
Brian