The point is that ramping up isn't really a thing because it will have already been producing at 100%. But that doesn't mean it isn't useful to address this, because it's still a generation method that generates power during the hours that solar doesn't. You would also then have even more generation during daylight hours, which isn't as valuable, but it still has economic value and can be sold for some smaller but still non-zero price per kWh.
In California the price actually is hitting zero sometimes during the day [1], which means that at that time, it's not economically valuable at all - nobody wants it. Rather, cutting back is valuable. Other kinds of electricity generation are easier to shut down, though, so they go first. This is graphed as "curtailment" [2].
Surplus electricity could hypothetically be put to use, but something would need to built to take advantage. (Perhaps batteries or some other load.)
> In California the price actually is hitting zero sometimes during the day
Sure, sure, but these are unusual times and not the common case. And if it was the common case that the price was zero during most daylight hours, it would be solar that goes bankrupt, since that's the only time it's generating. The other generation methods would still have the revenue from generating at night, which was the bulk of their revenue to begin with because of the expected price differential.
> Surplus electricity could hypothetically be put to use, but something would need to built to take advantage. (Perhaps batteries or some other load.)
Charging electric vehicles is an obvious one which will increase with their adoption. It's also likely that the grid will need some kind of storage because even if you have baseload plants to carry most of the nighttime load, the peak load of the day is just after sunset, and picking that up is going to require some kind of storage or peaker plants but the existing peaker plants are fossil fuels.
What baseload plants give you is to only need enough storage to make up the difference between what the baseload plants generate and that peak, and only for that couple of hours instead of the entire night.
Changing evs will become more popular, but is in time conflict with demand. The discharge time is at night, and people don't want to start the day on low, even if you do all your charging at worksites, which is the other challenge.
