A Flex Alert is a call for consumers to voluntarily conserve electricity when there is an anticipated shortage of energy supply, especially if the grid operator needs to use reserves to maintain grid integrity. When consumers reduce electricity use during a Flex Alert, it can prevent more dire emergency measures, including rotating power outages.
Who issues a Flex Alert?
A Flex Alert is issued by the California ISO, a nonprofit, public benefit corporation, which manages the flow of electricity along the high-voltage electric grid for 80 percent of California. The state’s three investor-owned utilities, Pacific Gas & Electric, San Diego Gas & Electric, and Southern California Edison, are responsible for delivering electricity from the high-voltage grid to its customers. Learn more about the California ISO.
What can trigger a Flex Alert?
A Flex Alert is typically issued in the summer when extremely hot weather drives up electricity use, making the available power supply scarce. This usually happens in the evening hours when renewable energy resources are no longer available, but temperatures remain high and consumers are returning home and switching on air conditioners, lights, and appliances.
Other contributing factors include:
- Unplanned power plant outages
- Fires that threaten or affect transmission lines
- Humid, hot weather and heat storms
When is a Flex Alert issued?
Flex Alerts are typically issued a day before it is needed, so consumers can prepare. However, grid emergencies can happen suddenly, prompting the ISO to issue a Flex Alert will little or no advance notice. When possible, Flex Alerts are targeted to regions of the state where the system is stressed.
What should consumers do when a Flex Alert is issued?
When consumers receive a Flex Alert, it is important for them to shift their energy use to the morning and early afternoon hours.
Morning before a Flex Alert, consumers should:
- Pre-cool their homes by lowering air conditioning thermostats to 72 degrees
- Close blinds and drapes to keep the sun from heating up the home
- Turn off unnecessary lights
- Use dishwashers, washing machines and other major appliances
- Set pool pumps to run early in the morning
- Charge mobile devices and laptops
- Charge electric vehicles
During a Flex Alert, when conservation is needed, consumers should:
- Set air conditioner thermostats to 78 degrees, if health permits
- Avoid using dishwashers, washers, dryers, and ovens
- Turn off unnecessary lights
- Unplug or turn off electrical devices that you are not using
- Keep blinds and drapes closed to prevent the sun from heating up the home
- Use fans when possible
How are rotating outages managed?
When there is not enough energy to meet the demand, the California ISO will direct the investor-owned utilities to rotate power outages within their service areas to avoid the collapse of the grid, and the possibility of the power being out for a much longer period of time.
The investor-owned utilities are responsible for determining the location and duration of the rotating outage within their service areas. Because the utilities are responsible for managing the rotating outages, consumers experiencing a power outage need to contact their electric power provider to learn when power will be restored.
How are consumers notified?
Consumers are encouraged to sign-up to receive an email notification when a Flex Alert is issued. Flex Alerts are also sent through the ISO Today mobile app, Twitter, Facebook, and promoted on the ISO’s website at www.caiso.com. The ISO also notifies the media to help increase awareness of the Flex Alert.