California Independent System Operator (CAISO)
CAISO runs most of California's high-voltage grid and its wholesale electricity market.
A grid operator is a separate organization from your utility. Your utility delivers power to your home. Programs for your home are on the pages for your state and your utility.
Wholesale prices through the day
Wholesale electricity costs more at some hours than at others. The chart averages a year of day-ahead prices, the prices a grid's market sets the day before, for each hour of the day.
In this grid the dearest hours over the last year were 7, 8 and 9 pm Pacific time.