Flex Alert in effect for next two days to help protect power grid stability

September 6, 2020


Consumers should prepare for the likelihood of rotating electric outages

FOLSOM, Calif. – The California Independent System Operator (ISO) issued a statewide Flex Alert, a call for Californians to conserve electricity, to prevent or limit expected rotating power outages today.

Flex Alerts are in effect from 3 p.m. to 9 p.m. today and tomorrow to reduce strain on the power system.

Temperatures during this current heat storm are expected to peak today, pushing demand for energy beyond levels of available supply. There is currently not a sufficient supply of energy to meet the high amounts of demand during the heatwave.

Based on the current forecast and without significant conservation efforts, rotating power outages are likely throughout the state today between 4 p.m. and 9 p.m.

Consumers can actively help by shifting energy use to morning and nighttime hours. Conservation can lower demand and avoid further actions, including outages, and lessen the duration of power interruptions. Consumer conservation efforts during a heat wave on Aug. 17 and 18 were key to preventing expected power outages.

Consumers were again instrumental in helping the grid avoid rotating outages on Saturday.

The ISO declared a Stage 2 Emergency on Saturday when wildfires took out 1,600 megawatts (MW) of resources in Southern California.

It is uncertain when that lost energy will return service, and likely will lower supplies available on Sunday, making conditions on Sunday more challenging and outages more likely.

The ISO also issued a Grid Alert Notice yesterday to inform market participants that supply will be tight today. The notice encourages energy producers to bid into the ISO's day-ahead market.

Consumers are urged to conserve electricity when the grid is most stressed in the afternoons and evenings, when temperatures remain high and solar production is falling due to the sun setting.

The ISO recognizes that reducing energy use during the hot time of the day is a hardship, especially for those working from home or for families with children schooling at home. However, if a large enough number of consumers conserve even in small ways, they can help grid operators avoid more serious system emergencies. Between 3 p.m. and 9 p.m., the ISO is urging consumers to:

  • Set air conditioning thermostats to 78 degrees, if health permits.
  • Defer use of major appliances.
  • Turn off unnecessary lights.
  • Unplug unused electrical devices.
  • Close blinds and drapes.
  • Use fans when possible.
  • Limit time the refrigerator door is open.

Consumers can also take steps to prepare for the Flex Alert by doing the following before 3 p.m.:

  • "Pre-cool" their homes, or lower air conditioning thermostats.
  • Charge electric vehicles.
  • Charge mobile devices and laptops.
  • Run dishwashers, washing machines and other major appliances.
  • Set pool pumps to run in the early morning or late at night.

For information on Flex Alerts, to get more electricity conservation tips, and to sign up for conservation alerts, visit the ISO's Flex Alert website. Visit the ISO's News page for more information on the heat wave's impacts on grid operations, and to learn more about alerts, warnings and emergency notices.

For updates on grid operations, follow us on Twitter at @California_ISO or @FlexAlert, or monitor system conditions in real time at ISO's Today's Outlook.

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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. Glossary of terms and acronyms

Click here 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.

This advisory is based on the best data available at the time of its release. Grid conditions can change rapidly and are
subject to change without warning. This forecast is accepted by the recipient on the condition that errors, omissions
and/or changes to the contents shall not be made the basis for any claim, demand or cause of action against the California ISO.