California

What to Know About Rotating Power Outages in California

Flex Alerts are the first in a series of steps to avoid unplanned power outages in California. If the call for voluntary conservation doesn't work, here are the next steps.

NBC Universal, Inc.

What to Know

  • A statewide Flex Alert is one of the steps the operator of the state's power grid can take to avoid unplanned power outages in extreme heat.
  • The call to voluntarily conserve power is typically issued during days of extreme heat in the summer.
  • From there, the state's power grid operator may issue alerts in stages before calling for rotating power outages.

California's power grid operator issued energy emergency alerts this week in an effort to prevent power outages as a statewide late-summer heat wave intensifies.

An Emergency Energy Alert 1 was issued Monday afternoon -- that's a step beyond one of the more common power outage prevention steps, a voluntary statewide Flex Alert. An Emergency Alert 2 was issued Monday evening.

A Flex Alert also was in effect Tuesday for the seventh straight day.

The alerts are some of measures that Cal ISO, the agency in charge of managing and maintaining reliability on the electric grid, can use to avoid power interruptions in the nation's most populous state. After Flex Alerts, grid managers have several options before rotating power outages, such as tapping backup generators, buying more power from other states and using so-called demand response programs, where people are paid to use less energy. Here’s what to know about Flex Alerts and the steps leading to rotating power outages.

What can I do to help prevent rotating power outages?

CalISO offers the following power conservation tips when a Flex Alert is issued.

  • Turning off unnecessary lights.
  • Using major appliances before 3 p.m. and after 10 p.m.
  • Setting air conditioner thermostats to 78 degrees or higher.
  • Use fans and keep drapes drawn.

How will I know when there's an urgent need to conserve power?

Cal ISO has a notifications page where you can sign up to receive updates. Check you local utility's page for other alerts. You also can check California's power forecast here.

What happens if Flex Alerts aren't enough?

Californians are familiar with Flex Alerts — a call for power conservation issued by Cal ISO in anticipation of high power demand. They usually happen during widespread extreme heat. The system operator also may issue the following alerts if the voluntary calls to conserve do not appear to be working.

  • Energy Emergency Alert 1: Real-time analysis shows all resources are in use or committed for use, and energy deficiencies are expected. Market participants are encouraged to offer supplemental energy and ancillary service bids. Consumers are encouraged to conserve energy.
  • Energy Emergency Alert 2: Cal ISO requests emergency energy from all resources and has activated its emergency demand response program. Consumers are urged to conserve energy to help preserve grid reliability. 
  • Energy Emergency Alert 3: ISO is unable to meet minimum Contingency Reserve requirements and controlled power curtailments are imminent or in progress according to each utility’s emergency plan. Maximum conservation by consumers requested.

How likely are rolling power outages in California?

On Saturday night, the state used about 44,000 megawatts of electricity, according to Cal ISO. By Tuesday, that's supposed to ramp up to more than 50,000 megawatts, nearing record levels of energy use set in 2006. But the state would rather curb demand to avoid that number than test the power grid's capability to respond.

“Our goal is to make sure that we do not reach that number," said Elliot Mainzer, president and chief executive officer of the California Independent System Operator.

At a Monday news conference, officials said the voluntary calls for conservation appear to be working, so far. Grid managers said they are closely monitoring supply-demand balance as extreme heat continues this week for most of California.

In August 2020, Cal ISO issued a Flex Alert followed by its first Stage 3 Alert since 2001. Eventually, the grid stabilized and utilities began restoring electricity that had been taken out of service. Temperatures around the state hit triple digits in many areas, and air conditioning use increased. In addition, cloudy weather from the remnants of tropical weather system reduced power generation from solar plants.

Why shut off power on a rotating basis?

Rotating outages can be a significant inconvenience, but they are a controlled measure used to manage emergencies. Without them, a widespread and more prolonged power disruption might result.

When was the last time California had rolling power outages?

Several hundred thousand Californians lost power in rolling blackouts in August 2020 amid hot weather. The state avoided a similar scenario last summer. Previously, the state ordered rolling outages during an energy crisis in 2001. Blackouts occurred several times from January to May, including one that affected more than 1.5 million customers in March. The cause was a combination of energy shortages and market manipulation by energy wholesalers, infamously including Enron Corp., that drove up prices by withholding supplies.

What happens when rolling blackouts are ordered?

The California Independent System Operator declares a Stage 3 power emergency and directs utilities around the state to shed their power loads. If your local utility determines a need to shut off power, the blackouts typically last about an hour.

After Cal ISO issues the power outages alert, it's up to local utilities to manage load. In Southern California during the summer of 2020, SoCal Edison announced that it had been instructed to begin rotating, one-hour service interruptions. Pasadena Water and Power also warned residents about the one-hour outages, while Anaheim officials said their outages would not last more than 15 minutes. The Los Angeles Department of Water and Power said the rolling blackouts did not affect residents of the city during the 2020 heat wave.

"The investor-owned utilities are responsible for determining the location and duration of the rotating outage within their service areas," according to Cal ISO. "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."

When rotating power outages are declared, residents should check timing with their local utility company.

How can I prepare for a power outage?

Below, you’ll find a few tips to get you through a power outage.

  • Update your contact information with your local energy company.
  • Have a back-up charging method for your phone and other devices.
  • Keep hard copies of emergency numbers and other important information.
  • Stock your emergency kit with flashlights, batteries, cash and first-aid supplies.
  • Do you know how to manually open your garage door? Try it out. 
  • Save operation of power-heavy appliances, such as dishwashers, washing machines and dryers, for early-morning and late-evening hours. 
  • Limit the opening and reopening of refrigerators.
Contact Us