Flex Alert - What Does that Mean for Pasadena?

When California issues a statewide Flex Alert, customers can wonder what does that mean for our community? Pasadena Water and Power has put together some helpful information to assist customers in understanding Flex Alerts.

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Current Status (Last updated July 6, 2023)

There is currently no on-going Flex Alert. Be the first to know by registering at FlexAlert.org

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What is a Flex Alert?

A Flex Alert is disseminated by the California Independent System Operator (ISO), a nonprofit corporation that manages the high-voltage electric grid for 80 percent of California. A statewide Flex Alert is essentially a “call-to-action” for consumers to voluntarily conserve electricity when there is a predicted shortage of energy supply, especially if the grid operator needs to dip into reserves to cover demand. When consumers reduce electricity use at critical times, it can prevent more dire emergency measures, including possible power outages.

Typically, a Flex Alert is issued in the summer when extreme heat and high temperature increases the electricity demand. Flex Alerts are usually issued a day in advance of the predicted supply gap, so consumers can better prepare for the event, although if a grid emergency takes place the ISO can issue a Flex Alert with little to no advance notice.

What to do During a Flex Alert

Here are some simple ways to conserve energy during a Flex Alert:

  • Adjust your thermostat to 78 degrees or higher.
  • Postpone using heat-producing appliances such as an oven, dryer, dishwasher, etc., until after 9pm, or the designated time stated by the ISO (each Flex Alert issued varies).
  • Charge up your EV prior to peak hours.
  • Close windows and doors, and use window coverings to prevent heat from entering your home.
  • Turn off unnecessary lights.
  • Unplug phone chargers, power strips and other equipment when not in use.
  • Visit the CAISO Flex Alert website to learn more.

Saving Water During a Flex Alert

Using water wisely is always important, and conserving water during a Flex Alert can also help reduce strain on the power grid.

  • With higher temperatures, adjust your outdoor watering methods to ensure maximum water efficiency.
  • Only water your landscape before 9 AM or after 6 PM to prevent evaporation loss.
  • Be mindful of indoor water use too.
  • For more tips, please visit our Save Water page.

How Does a Flex Alert Affect Pasadena?

Pasadena receives power from a variety of sources, click here to learn more about where our power comes from. Pasadena also has the added benefit of having its own power plant, known as the Glenarm Repowering Plant, which is owned and operated by PWP. Glenarm is a peaker plant and can generate power within 10 minutes to meet most of the City’s power needs or to operate at the request of the California Independent System Operator (CA-ISO) to support the state’s power grid with new generation. Although Pasadena has this local resource, we are still part of the regional electric grid managed by the CA-ISO. The status of any power supply is a constant change, which means that at a moment’s notice, PWP may have to implement rotating power outages, even if it's generating power at the Glenarm Plant. When PWP receives a directive to curtail load from CA-ISO, we need to assist immediately.

Although these cases are rare, it’s important for customers to realize how ongoing energy conservation can make a difference. If we do our part to reduce energy, especially on high-heat days, we can help to lessen the impact on the state's power grid and ensure communities throughout California have the electricity they need.

Recent Flex Alerts

  • September 7-9, 2022: CA ISO extended the Flex Alert again to include Thursday, 9/8 from 3 to 10 PM, and Friday, 9/9 from 4-9 PM. Learn more at caiso.com.
  • September 6, 2022: CA ISO extended the Flex Alert again to include Tuesday, 9/6 and Wednesday, 9/7 from 4 to 9 PM. Read more.
  • September 5, 2022: CA ISO extended the Flex Alert again to include Monday, 9/5 from 4 to 9 PM. Read more.
  • September 4, 2022: CA ISO extended the Flex Alert again to include Sunday, 9/4 from 4 to 10 PM. Read more.
  • September 3, 2022: CA ISO extended the Flex Alert again to include Saturday, 9/3 from 4 to 9 PM. Read more.
  • September 2, 2022: CA ISO extended the Flex Alert into Friday, 9/2 from 4 to 9 PM. Read more.
  • September 1, 2022: CA ISO extended the Flex Alert into Thursday, 9/1 from 4 to 9 PM. Read more.
  • August 31, 2022: CA ISO issued a Flex Alert for 4 to 9 PM on Wednesday, 8/31. Read more.
  • August 17, 2022: CA ISO issued a Flex Alert for 4 to 9 PM on Wednesday 8/17. Read more. 

What is the Difference between Rolling Blackouts and a Brown Out?

rolling blackout is an intentional electrical power shutoff that takes place over different periods of time in different parts of a city or distribution region. Rolling blackouts are sometimes necessary for situations where the demand for electricity exceeds the power supply capability of the network, such as during extreme heat waves. Flex Alerts are an attempt to prevent utilities from having to resort to rolling blackouts by encouraging customers to conserve in anticipation of high demand due to heat or other circumstances.

As a locally owned utility, PWP has the added benefit of having relationships with its customers. PWP has been able to establish agreements with some of the city's largest energy users (commercial customers) to assist with curtailing energy use immediately if PWP requests it. This is part of the utility's Voluntary Load Curtailment Program and helps minimize the likelihood that PWP would need to issue rolling blackouts in the event of strain on the power system.

brownout is a decrease in voltage in the electrical power grid, these can be intentional or unintentional depending on the circumstances. If intentional, brownouts are also used for situations where demand exceeds supply capability. During a brownout, customers typically still have power, but experience interment interruption like lights flickering or dimming.

Both tactics are used as a last-resort and are mean to prevent larger unplanned grid power outages.

Due to PWP's Glenarm Repowering Plant, Pasadena rarely utilizes rolling blackouts or brownouts to manage load and demand cycles, since our plant can provide power for the community if the grid cannot. PWP's Voluntary Load Curtailment Program also assists with this.

Stay Informed

To stay up-to-date on any Flex Alerts, or other important utility information, follow PWP on Facebook or Twitter!

One of the best ways to stay informed of outages in your neighborhood is through our Outage Management System (OMS).

Registered customers receive direct cell phone alerts when there is a service outage in the area that provides estimated times of restoration. To sign up, simply update your account information and provide a cell phone number that PWP can use to during an outage.