> Are there any >1GWh thermal battery facilities?

I don't know about that, but for comparison, the "world’s biggest battery storage system" opened last year in California[0] at 400MW / 1,600MWh.

[0] https://www.energy-storage.news/expansion-complete-at-worlds...

Which is a lithium ion battery facility. Not a thermal batter facility.

Yes, I realise that. That's why I said "I don't know" and "for comparison".

My point was that GWh-scale thermal battery proposals would be competing with already existing (and possibly cheaper) chemical batteries, and that energy storage on this scale is not unheard of.

The point is that current energy storage facilities are too small for fully renewable grid (or arguably even 60% renewable grid).

Even as a nuclear supporter I would welcome more renewables if we had cheap scalable storage, which no one has it seems. (at least no one pointed out such project in the entire thread)

A minor caveat: some regions have large hydroelectric generation, which doubles as a great energy storage site. Countries seem to be able to manage a roughly 1:1 ratio between intermittent sources and hydroelectric generation. Sweden is managing to decarbonize it's grid with ~1/3rd each of nuclear, intermittent sources, and hydroelectric.

But for much of the world what doesn't have this option, nuclear remains the most viable energy source.

Yes, that's what I meant by "scalable". You can't just continue picking low hanging fruit forever.

Btw even the Sweden example uses nuclear for decarbonization of the grid ...

Certainly there are >1GWh thermal storage systems. I'm not sure if any are set up to generate electricity though.

The only deployed thermal storage systems are in solar thermal arrays. Those have costs that aren't not competitive with nuclear, and they're still subject to seasonal output variability due to weather and Earth's inclination.

And district heating systems. Where a 1-2GWh thermal accumulator will be used.

District heating systems distribute heat, usually scavenged from a power plant. They don't store heat really - they do in a pedantic sense in that heat is "stored" in the distribution pipelines, but not in the sense of a battery. And they don't transfer heat at gradients large enough to generate electricity effectively.

They store heat in the sense that one of the components is a giant thermal accumulator.