Grid Operator Calls First Flex Alert of the Summer

Updated Aug. 18

California's grid operator called on customers to lower their energy use for several hours Wednesday afternoon because temperatures were projected to spike across the state, driving up demand on the grid from increased air conditioning use.

“Consumers are urged to conserve electricity, especially during the late afternoon and early evening, when the grid is most stressed due to higher demand and less solar energy,” the California Independent System Operator stated in an Aug. 16 announcement.

Demand on the grid peaked just before 6 PM on Tuesday at 45,198 MW, which was slightly above the forecast peak of 45,166 MW, according to CAISO. Peak demand on Aug. 17 was projected to be a bit below that at 44,936 MW.

CAISO’s Tuesday afternoon flex alert asked for conservation from 4 PM to 9 PM on Wednesday to avoid over taxing the grid. That day, actual demand was well below the forecast peak, reaching 42,643 at 6:00 PM.

The highest demand on the grid in the last decade was 50,116 MW on Sept. 1, 2017. Today there is more solar and wind power feeding into the electricity system to meet such extremes, but solar energy drops off as the sun sets while demand stays high.

Part of the state is also suffering from poor air quality because of wildfires. The Bay Area Air Quality Management District issued a Spare the Air alert for Tuesday and Wednesday that asked people to cut back on their driving because of air pollution from fires in Northern California. However, a light rain fell on the Bay Area on Wednesday that helped clean the air.