featured graphic for Flex Alert from the California Independent System Operator (Cal ISO)

Cal ISO calls for larger voluntary cuts in energy use as Flex Alert announced for Tuesday, September 6

Record-breaking temperatures are leading to historic high forecasted demands for power, putting even greater strain on the California Independent System Operator (ISO) electrical grid and significantly increasing the likelihood of rotating outages unless consumers can reduce their energy use even more than they have so far.

“This is an extraordinary heat event we are experiencing, and the efforts by consumers to lean in and reduce their energy use after 4 p.m. are absolutely essential,” said Elliot Mainzer, the California Independent System Operator’s president and CEO.

“Over the last several days we have seen a positive impact on lowering demand because of everyone’s help, but now we need a reduction in energy use that is two or three times greater than what we’ve seen so far as this historic heat wave continues to intensify.”

The ISO declared an Energy Emergency Alert 1 (EEA) Monday morning from 5 to 9 p.m. today. That emergency designation signals to utilities and consumers that all resources are committed or forecasted to be in use, and that energy deficiencies are expected. A Flex Alert urging consumers to reduce their power use in the late afternoon and evening is also in effect today and tomorrow, marking seven consecutive days the call to cut demand has been issued.

As they monitor a host of factors including wildfires and generator availability, grid operators will determine later today if the emergency notifications need to be elevated to an EEA 2 or beyond.

EEA 2 would trigger deployment of a suite of emergency tools designed to keep supply and demand for the power system balanced during extreme conditions, and potentially freeing up to a few thousand megawatts of additional resources.

If conditions continue to deteriorate, an EEA 3 may be declared. If reserves are then exhausted the ISO would instruct utilities in its service area to manage shedding load.

Utilities make the determination of how best to spread and rotate the outages across for their service territory, with the goal of keeping them as short as possible. For two days in August 2020, outages affecting about 800,000 homes and businesses lasted anywhere from 15 minutes to about 2 ½ hours, marking the first time outages were ordered in California due to insufficient supplies in nearly 20 years.

“We never want to get to that point, of course,” Mainzer said, “but we want everyone to be prepared and understand what is at stake. We can’t control the weather, but we really can bend the demand curve and get through this successfully if everyone doubles down and reduces their energy use as much as possible.”

For more information, see our Rotating Power Outages fact sheet.

Forecasted loads are currently very high today and tomorrow, with Tuesday showing peak demand at 51,145 megawatts (MW), which would set a new record from the previous high of 50,270 MW in 2006. Wednesday’s load is forecast at 50,002 MW. For context, see our Peak Load History report.

The ISO is projecting supply deficiencies of 400 to 3,400 MW between the hours of 5 p.m. and 9 p.m. tomorrow.

Consumer and commercial demand response, including Flex Alerts, has been helping to extend tight resources over the past week, with a load reduction of around 1000 MW for each of the past several days, with more now needed as the heat continues to increase.

Before a Flex Alert takes effect, consumers are encouraged to pre-cool their homes and use major appliances earlier in the day, when solar supplies are abundant. Cooling homes in advance minimizes discomfort during the Flex Alert.

Reducing energy use during a Flex Alert can help protect the power grid during tight supply conditions and prevent further emergency measures, including rotating power outages. Turning your thermostat to 78 degrees or higher, health permitting, not using major appliances such as your dishwasher or washing machine, and turning off all unnecessary lights are among the most effective ways to reduce residential energy use.

For information on Flex Alerts, and to find more electricity conservation tips, visit FlexAlert.org.

Tips before a Flex Alert:

  • Pre-cool home by setting the thermostat to as low as 72 degrees
  • Use major appliances:
    • Washer and dryer
    • Dishwasher
    • Oven and stove for pre-cooking and preparing meals
  • Adjust blinds and drapes to cover windows

Tips during a Flex Alert from 4 p.m. to 9 p.m.:

  • Set thermostat to 78 degrees or higher, if health permits
  • Avoid using major appliances
  • Turn off all unnecessary lights

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.

Follow developing grid conditions at the ISO’s News webpage, under the System Conditions Bulletin, or follow us on Twitter at @California_ISO.

Click here (pdf) to learn more about System Alerts, Warnings and Emergencies. Follow grid conditions in real time at ISO’s Today’s Outlook, or download the free ISO Today mobile app.

The article above was released by the California Independent System Operator (Cal ISO).