Flex Alert extended to Saturday: conservation needed from 4 p.m. to 9 p.m.

July 10, 2021


Electric grid strained due to high heat and fire-threatened transmission lines

FOLSOM, Calif. – A rapidly growing wildfire in Southern Oregon that is threatening transmission lines used to import energy to California, along with continued extreme heat throughout the state, are putting new stresses on the electric grid, making the need for strong conservation much more critical.

The California ISO has extended a statewide Flex Alert for a second consecutive day (Saturday, July 10) and is strongly encouraging consumers to conserve as much electricity as possible from 4 p.m. to 9 p.m. to help keep the grid stable. Successful conservation when the grid is under such duress can alleviate the need for rotating outages that could be taken as a last resort when demand for power continues to outstrip supply.

Conditions on the electric grid were already a challenge Friday, when much of California was experiencing triple-digit temperatures, some generating capacity was not available and a Flex Alert was called for the late afternoon and evening.

ISO data show demand for electricity did start to drop once Friday’s Flex Alert was in effect and consumer conservation began to take hold. But conditions deteriorated quickly as the Bootleg Fire continued to grow and posed an imminent threat to transmission lines leading into the California Oregon Intertie (COI).

The COI is not only used to import electricity from the Pacific Northwest to the electric grid managed by the ISO, it also imports power into other grid balancing authorities and the state of Nevada.

The fire has been a wildcard for grid operators since it began Tuesday in rural Klamath County reportedly from a lightning strike. The wind-driven blaze, which has forced evacuations and is not projected to be contained for another two weeks, had burned a little less than 40,000 acres by Friday, nearly doubling in size from the day before. By Saturday morning, it had nearly doubled in size again and burned more than 76,000 acres.

On Friday afternoon, the ISO issued a formal Grid Warning, which gives the grid operator authority to initiative emergency demand response programs that compensate electricity customers for conserving. That Warning was canceled at 10 p.m. Friday, about the time demand for electricity is typically low, but could be reinstated today if conditions warrant.

Conservation is the best tool to quickly bring down demand on the grid, and when the Flex Alert is in effect again today between 4 p.m. and 9 p.m., 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 today, before the Flex Alert takes effect at 4 p.m. 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

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.

In addition to Flex Alerts, 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. And on Saturday, the ISO issued an order that requires generators and transmission operators to postpone any planned outages for routine equipment maintenance, ensuring all grid assets are available for use

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.