Its not, its a public relations exercise so they don’t have to resort to Enron style solutions.
(bolding mine)
California’s electricity is apparently powered by male cow manure (i.e. there’s more than a bit of bovine scatology at work here).
The latest statistics I could find are from 2015, but I doubt that things have changed much. Solar accounts for a whopping 6 percent of California’s electricity supply. Natural gas, aka the type of energy they don’t need to rely on (rolls eyes) is by far the largest single supplier of energy at 44 percent. Nukes account for 9 percent, coal 6 percent (as much as the solar that they apparently depend on, ahem…), wind 8 percent, geothermal 2 percent.
Biomass, geothermal, solar, and wind all combined add up to about 18 percent. Fossil fuels (coal, natural gas, and oil) are at about 50 percent. Hydro is a bit over 5 percent.
Full statistics here: 2018 Total System Electric Generation
If all of the solar power stopped working, the rest of the energy suppliers could crank things up just a tad and no one would notice the difference.
I guess this is why California is the land of make-believe.

Read my post, ferchissakes!
Where does
“Said President Picker, “When the sun goes away, so does the energy that powers our renewable solar
panels. If millions of Californians turn off appliances and power strips to unplug from the grid
during the eclipse, we can let our hard working sun take a break. We don’t have to rely on expensive
and inefficient natural gas peaking power plants, we can have cleaner air, we can keep our system
reliable, and we can send a message to the rest of the country that we can do all of that without being
forced to rely on fossil fuels as the only foundation of our electricity.””
say anything about daytime vs. nighttime?

Where does
<snip>
say anything about daytime vs. nighttime?
I think mhendo was referring to this part of his post.

As you can see, it’s basic a public awareness announcement regarding power usage in general, using the eclipse as a convenient excuse. There’s no suggestion, anywhere in the press release, that a failure to reduce energy usage on that particular morning will place any real strain on the power supply.
Basically, daytime vs. nighttime doesn’t matter in this case because there’s no real energy shortage. It’s all political posturing.

Minutes. A solar eclipse lasts for minutes, not hours. A lunar eclipse can be several hours long, but the shadow of the moon on the earth is very small and moves very fast. Even the penumbra (partial eclipse/broader shadow) will affect any given array for no more than about ten or fifteen minutes. I saw a total eclipse in Portland about 30-some years ago, and it was over very quickly.
The total eclipse lasts for a couple of minutes – about 2 minutes for the one this August – but from the beginning of the partial eclipse to its end is about 3 hours.
The conventional wisdom is that, even if solar were one’s primary energy source, one would still need quick-response peaking plants like natural gas to fill in when solar output is low. I think that this group is trying to challenge that conventional wisdom, saying that even the peaking plants wouldn’t be necessary, because people can instead cut their consumption during those times. It’s not a point relevant to the current world (where solar is such a small piece of the pie), but to a hypothetical future world where we’ve completely weaned off of fossil fuels.
In the not-too-distant future, EVs connected to the grid could help with surges in demand or dips in production. There would still be a need for on-demand energy production, but those power plants could run on a renewable fuel, such as biodiesel.