True, but that's a bit like turning the problem on its head, the important part is that solar panels do help during California's peak, which wouldn't be true in most other places because the peak would be happening much after 5PM.

...and the solar panels would help better if placed optimally - in the open with no residential shade trees or neighboring houses; grouped for efficient maintenance and electrical conversion; on the ground where they could be adjusted as needed for time of year.

Residential roofs are about the worst place to put a solar panel imaginable.