California ISO extends Flex Alert a second day through Saturday

July 9, 2021


Voluntary conservation and other actions taken to support grid reliability

FOLSOM, Calif. – The California Independent System Operator (ISO) has extended a statewide Flex Alert for a second day to avoid a possible shortage of energy as extreme heat in California and a growing wildfire in Southern Oregon threatening transmission lines continue to strain the state’s electric grid. 

When the Flex Alert is in effect again between 4 p.m. and 9 p.m. on Saturday, July 10, consumers are strongly encouraged to conserve energy by:

  • Setting thermostats to 78 degrees or higher, if health permits
  • Avoiding using major appliances
  • Turning off all unnecessary lights

Consumers are also encouraged to use fans for cooling and unplug unused electrical items.

Earlier in the day, before the Flex Alert takes effect and when solar energy is abundant, consumers are encouraged to take these steps to be comfortable and help grid operators balance electricity supply and demand: 

  • Pre-cool your home by lowering the thermostat
  • If you need to use your major appliances, do it before the Flex Alert is in effect, when solar energy is plentiful
  • Close window coverings to keep your home or apartment cool
  • Charge electronic devices and electric vehicles so there’s no need to do it later, when solar generation is down

In addition to the Flex Alert, the ISO is using multiple tools to help keep the grid stable, including a solicitation on July 1 to generators in the Western region to procure additional resources. The ISO is also working with business and industry to help them reduce electricity consumption at critical times.

Conditions on the grid became more challenging Friday afternoon when the rapidly expanding Bootleg wildfire in southern Oregon was threatening electric transmission lines, putting limits on the amount of energy that can be imported to California.

Voluntary conservation has helped keep the electric grid stable during past times of high stress on the grid, including last month when triple-digit temperatures across the West strained the system with higher demand for power.

Grid operators continue to closely monitor conditions and will have additional announcements as needed.

As California’s ability to store solar and wind energy with batteries or other technology continues to advance, crucial evening hours will be less of a challenge and similar emergencies rarer. But for now, collective action to conserve is our most effective way to support grid reliability.

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.