Statewide Flex Alert issued asking California residents to reduce power during heat wave

UPDATE: Shortly before 10 p.m. the California Independent System Operator (ISO) announced it terminated its Stage 3 Emergency. All power has been restored statewide.

A blistering heat wave over the next several days is prompting the California Independent System Operator to issue a Flex Alert for Friday, which means residents are being asked to reduce power usage from 3 p.m. to 10 p.m.

Shortly after 5 p.m., demand on the system was so severe that Cal-ISO declared a Stage 2 Emergency.

However, around 8 p.m. a Stage 3 Emergency was issued. Cal-ISO says they are taking reports of outages. The city of Anaheim says they are experiencing rolling power outages. 

Outage times may vary, as blackouts in Pasadena are expected to not last more than an hour, while Anaheim officials said their outages should last no longer
than 15 minutes. 

"The ISO is working closely with utilities and neighboring power systems to manage the strain on the grid to limit any potential power disruptions,'' according to a statement from Cal-ISO.

"California will be experiencing near-record or record-breaking heat, up to 10-20 degrees above normal in some areas," ISO officials said, noting that the heat will increase electricity demand, primarily due to the use of residential air conditioning. "Prolonged heat over several consecutive days is expected to drive electricity demand higher, as nighttime temperatures are also forecast to be above average."

Excessive heat warnings will be in effect throughout the weekend for most of the Southland.

The main concern is people running air conditioners longer will put a strain on the power grid. Power supplies also could be even tighter, as cloud cover is expected to cause a drop in solar power.

"The cloud cover obviously reduces the solar output and so that further tightens our electricity supplies," said Anne Gonzales, a California ISO spokeswoman.

Energy conservation tips from ISO include:

• Turning off unnecessary lights;
• Using major appliances, such as washers, dryers, vacuum cleaners, and dishwashers, before 3 p.m. and after 10 p.m.;
• Setting air conditioner thermostats to 78 degrees or higher;
• Using fans; and
• Keeping drapes drawn.

Conservation measures can help the power grid keep up with demand and supply, and avoid power interruptions, experts said.

CAL-ISO says by federal law, they must maintain power reserves, so if demand outstrips supply, there might be outages.

"We're asking to conserve some now so electricity can keep flowing," said Gonzales.

Conservation during the pandemic presents a new challenge, as many families are using electronic devices such as tablets, cell phones and computers working from home, and learning from home.

"What we are asking is people take simple steps that may help," said Tamar Sarkissian, a PG&E spokeswoman.

Additional recommendations from PG&E include:

• Turn off pumps to swimming pools
• Turn off unused appliances

KTVU and CNS contributed to this report.