I know of at least LA, SD, and Sacramento have publicly owned electric providers.
They buy a lot of power from various investor owned utility companies.
There are about 50 municipal electric utilities scattered throughout CA (San Diego is not one of them, BTW). They serve about 20% of the customers in the state but purchase their power from privately owned companies, for the most part. The larger ones may have local power plants or hydro-electric generation and all have some solar. But they all depend on the PG&E, Edison or San Diego G&E to some extent.
PG&E provides electricity to some parts in Sacramento.
And they buy their power wholesale from PG&E.
There are quite a few municipal electric utility agencies and quasi-agencies.
Some just act as billing agents. Some aren’t even that, acting as “cost plus” in-paper-only-providers of “green” power. For an example, compare San Francisco vs Oakland electric bills - oddly, SF has less boondoggles attached.
Some really are utilities in a proper sense. LADWP and SMUD maintain their own distribution lines, as do a few irrigation districts.
Its quite a zoo really.
What none of them do is the difficult work of electric transmission and rural/fill in the blanks distribution, the point where there are liabilities for fire risk, extremely long runs of power lines through forests and brush covered hills, nor do they operate the electric grid, which is a single entity.
That is, PG&E and to a lesser degree So Cal Ed tie them all together and operate the system as a whole, and provide service in places nobody else wants to.