Indeed. NG currently makes up 47% of California's electricity, nuclear 9%, so that is 56% right there. Solar and wind are 14% and 7%, so that means we'll need a 267% increase in their output (assuming no increase in other renewables) just to replace NG/nuke current output, then say 25% on top of the total for EVs and an additional increment for any other uses we switch to electricity. Since RE has lower capacity factors than NG/nuke plants, the actual capacity increase has to be a several times multiple of the above.
As we've got the fourth-lowest usage per capita in the U.S. already thanks to the past 40+ years of energy-efficiency regulations, future major "capacity" gains from improved efficiency seem unlikely.