A substantial amount of the power generation in California comes from solar, whose output peaks at noon and drops off substantially in the evening. This leads t

A substantial amount of the power generation in California comes from solar, whose output peaks at noon and drops off substantially in the evening. This leads to a situation in the 4-10 PM range where power usage is still at peak levels, but power generation has fallen off due to the drop in solar output. Natural gas peaker plants are used to fill that shortfall. The California ISO publishes near real-time statistics on the grid where you can see this effect: https://www.caiso.com/TodaysOutlook/Pages/supply.html https://www.caiso.com/TodaysOutlook/Pages/supply.html