Folsom CA— The California Independent System Operator(ISO), with extreme heat forecast for much of California and the Southwest, has issued a statewide Flex Alert to encourage electricity conservation tomorrow, June 17, 2021 from 5 p.m. to 10 p.m. to reduce stress on the grid and avoid power outages.When past Flex Alerts have been called, consumers have answered the call and cut back their electricity use. Those actions have helped California avoid or limit power outages that can, if conditions persist or worsen, become necessary when demand for electricity outstrips capacity.“The public’s help is essential when extreme weather or other factors beyond our control put undue stress on the electric grid,” said Elliot Mainzer, president and chief executive officer of the ISO.
“We have seen the huge impact that occurs when consumers pitch in and limit their energy use. Their cooperation can really make a difference.”While Flex Alerts are normally 4 p.m. to 9 p.m., the hours of conservation for this event are 5 p.m. to 10 p.m. due to operational needs. The statewide call for conservation is critical because when temperatures hit triple digits across a wide geographic area, no state has enough energy available to meet all the heightened demand,primarily due to air conditioning use.
For the next several days, much of California and the Southwest are expected to see triple–digit heat with above normal temperatures spread more broadly across much of the Western United States. And like California, other Western states –including Arizona and New Mexico –are experiencing similar stressful grid conditions due to the extreme heat. Under such conditions, evening is the most difficult time of day for grid operations, especially in persistent hot weather when evening temperatures stay warm, because demand for electricity remains high as solar energy diminishes.
By collectively taking a few simple actions, electricity use can be reduced enough to keep power on for everyone. Last August and September, for instance, Californians heeded multiple Flex Alerts and Gov. Gavin Newsom’s call for a concerted response to emergency condition and reduced electricity use by 1,000 to 3,000 megawatts. That is enough electricity to power up to 3 million homes, and the conservation likely prevented subsequent and more severe rotating outages last August and September.
If demand still outstrips supply after Flex Alerts and other measures are taken, the ISO could again order utilities to begin rotating power outages. That would extend available power supplies and guard against longer and more extensive disruptions while protecting high–voltage transmission lines from damage.As California’s ability to store solar and wind energy with batteries or other technology continues to increase, the crucial evening hours will be less challenging. But for now, concerted action to conserve is our most effective way of keeping the grid working for everyone.
Conservation Tips
• Before 5 p.m., “pre-cool” buildings by setting air conditioning thermostats lower
than usual; also, charge electronic devices and electric vehicles; and run
dishwashers, washers and dryers and other major appliances
• After 5 p.m., set thermostat at 78° or higher
• Cool with fans and draw drapes
• Turn off unnecessary lights and defer use of appliances
Learn more: http://www.flexalert.org (Available in Spanish and Vietnamese)
Flex Alerts

• A Flex Alert is issued by the ISO when the electricity grid is under stress because of generation or transmission outages, or from persistent hot temperatures.
• Consumers are urged to voluntarily conserve electricity to help avoid more serious steps to protect the power grid, including local rotating outages.
• Click here to learn more about Flex Alerts and Stage Electrical Emergencies.