When we quote a firm cost, prices start at about $5500 for overhead and about $18500 for underground (we're GCs also and this includes trenching and concrete sidewalk repair), if things are straightforward. This is mostly due to the total pain in the butt that is PG&E, and having to leave some margin of error in the price for unexpected PG&E complexities. Expect the paperwork to suck up the hours, fill out the same form twice, email a rep who then quits and is replaced by another rep who's just learning how to do the job... One project during the pandemic took 2 years for PG&E to upgrade their local transformer, so you're just waiting around, having already spent the money on the materials and gotten the green tag from the city.
Without trenching and concrete work I bet it would end up being about $12000, if it's not an inconvenient route to the box in the sidewalk. Sometimes PG&E requires that you go out the bottom of the box and you end up working in a trench 6' deep.