The California Independent System Operator (CAISO) issued a call for voluntary electricity conservation, for Wednesday, July 28, due to predicted high energy demand and tight supplies across the West.
With higher-than-normal temperatures in the forecast for parts of interior Northern California, the power grid operator on July 27 said it was predicting an increase in electricity demand, primarily from air conditioning use.
CAISO issued the statewide Flex Alert for 4 p.m. to 9 p.m.
A Flex Alert is issued by CAISO when the electricity grid is under stress because of generation or transmission outages, or from persistent hot temperatures.
“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 solar energy production falling,” the grid operator said. “Consumers are also asked to turn off unnecessary lights, delay using major appliances until after 9 p.m., and set air conditioner thermostats to 78 degrees or higher, if health permits.”
CAISO in a July 28 system conditions bulletin said that several conditions were impacting the grid.
“While the temperature forecast is slightly above normal for parts of California, and demand is projected to be moderately high, there are weather and demand uncertainties, which affects our forecasting data,” it said.
“We are also monitoring several wildfires in and outside of California that could threaten generation and transmission, limiting energy supplies. And there is always the possibility of equipment failure and forced outages on the system,” CAISO said.
“All of these conditions taken alone would normally have minor impacts to the grid, but as the power grid operator, the ISO must plan for unexpected events, such as wildfires or forced line or plant outages, that could whittle into energy supplies and affect grid reliability. To keep the grid stable, the ISO is asking Californians to reduce electricity use from 4 to 9 p.m. today, the critical time of need on the system, when solar production is ramping down and electricity demand can remain high. If everyone makes some small adjustments, the extra supplies can act as a shock absorber in case of unexpected events today,” the July 28 system conditions bulletin said.
“The ISO is not anticipating any rotating power outages at this time. We believe consumer conservation will be key to getting through the most critical period this evening.”
The ISO said it would decide if another Flex Alert is needed for Thursday, July 29, following the close of the market on the afternoon of July 28 and a review of updated weather forecasting.
Earlier this month, a rapidly growing wildfire in Oregon – the Bootleg Wildfire – that threatened transmission lines used to import energy to California and extreme heat throughout California pressured California’s electric grid, prompting CAISO to extend a statewide Flex Alert.