California is already short of power. They claim to have 30% renewables, but that’s only within California. Given that California must import a lot of electricity from Nevada and Oregon, its actually use of renewables is about 10%
Its also why they will continue to have worse and worse black-outs in the summer. If they refuse to build more power plants, they will need to rely on other states, who are also experiencing the same heat they are.
For June 2020, they generated equal amounts of wind/solar and natural gas electricity, plus nuclear and hydro. So well over 50% renewable: http://www2.eia.gov/state/?sid=CA#tabs-4 They imported power as you pointed out, more energy than the wind/solar (see consumption by source page).
Their imports come from Oregon as you said, but Oregon is mostly hydro. (click on state at the top of the page). But a much bigger exporter to California (by 3x) is Arizona which is mostly gas, coal and nuclear.
I doubt their net use of renewables is as low as 10%, probably more like 25% However the numbers on that page I linked are a good month (June) when they don't have to rely on gas as much. The best metric on that page is consumption by source by year (2018) That shows natural gas usage, not just electricity, but also heating, far exceeding anything else. And it shows imports of electricity (mostly fossil) exceeding renewables.