It's still a good thing, but isn't this misleading, since solar capacity would only be able to run 1/3 of the day-ish? Not sure about wind but again guessing it's not 100%.
https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...
https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...
Again, it all depends on the location. The US has a pretty high capacity factor for nuclear at over 90%, but the UK has it at 60-80%. Wind farms can go over 50%.
For solar/wind, this can literally never be 100%, or even close to it.
For Coal/Nuclear/Gas it just comes down to maintenance duration.
The other thing to remember is that production and storage capacity are cheap to expand, so the better question is how often it’s the case that it’s dark at times of peak demand long enough to exhaust the grid storage capacity. Currently, that’ll be the case but I’d bet that a decade from now it’ll be much less common.