FOLSOM, Calif. – The California Independent System Operator (ISO) has extended a statewide Flex Alert for a second day, issuing a call for voluntary electricity conservation for tomorrow, Sept. 9, from 4 p.m. to 9 p.m., because of hot weather affecting much of California and the West, and tight energy supply margins in the market.
Tomorrow’s Flex Alert follows today’s conservation call, also due to above-normal temperatures in the western states. Consumers are urged to conserve electricity from 4 p.m. to 9 p.m. on both days by setting their thermostats to 78 degrees or higher, and deferring use of major appliances and unnecessary lights during that time.
The ISO also issued a system-wide Restricted Maintenance Operations (RMO) order for today and Thursday from noon to 9 p.m., delaying routine maintenance of generation and transmission equipment so that all available resources are online for the critical evening time.
The Flex Alerts have been issued due to above-normal temperatures leading to high electricity demand in California and parts of the western US, narrow margins of supply, and cloud cover creating uncertainty for renewable generation forecasts.
Temperatures in the Northern California inland region are forecast to be 3-10 degrees warmer than normal. In Southern California, temperatures are expected to be 5-10 degrees warmer than normal through the weekend, primarily for the interior, although coastal regions are forecast to see some warming as well.
Above-normal temperatures throughout much of the interior western US are also expected this week, with some cities seeing a potential for record-breaking heat. Widespread heat waves affecting other western states limits the California ISO’s ability to import energy from neighboring power grids.
The ISO is predicting an increase in electricity demand, primarily from air conditioning use. The increase can stretch electricity supplies thin and cause strain on our power grid, especially in the late afternoon and evening, when solar production goes offline and wind generation is uncertain, however, temperatures and electricity demand remains high.
Consumers are urged to conserve electricity, especially during the late afternoon and early evening, when the grid is most stressed due to higher demand and solar energy production falling.
Reducing energy use during a Flex Alert can help stabilize the power grid during a time of tight supply conditions, and prevent further emergency measures, including rotating power outages.
For information on Flex Alerts, and to get 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
- 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 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.