Comment by nostrademons

With continued solar adoption, "off-peak" will shift from "overnight" to "midday", at least if the utilities are properly passing along their costs. I think it might already have in California - I saw someone in r/electricvehicles saying that they get a cheaper rate for daytime charging. The idea that overnight has the cheapest electricity rates is an artifact of the fossil-fuel-dominated electric grid economics, and (physically speaking) there's no reason for it to hold true with renewables.