Grid Operators Again Call for Energy Conservation to Avoid Rolling Blackouts

California's grid manager is calling for another round of aggressive conservation as a historic heatwave pushes the state toward a power emergency for the second straight day.

Elliot Mainzer, chief of the California Independent System Operator (CAISO), says the state was spared rotating blackouts Tuesday night only because of a strong response to an emergency alert that went out to 27-million people.

"We're going to need the exact same type of response tonight," he said.

A statewide Flex Alert for power conservation kicks in at 4 p.m. and continues through 9 this evening. Consumers are asked to set thermostats to 78 degrees or higher, if their medical conditions permit that. Grid managers also ask that people turn off unnecessary lights and avoid using major appliances or re-charging electric cars during the Flex Alert period.

Some 35,700 people lost electricity Tuesday in the South Bay and beyond, including Cupertino, Campbell, San José, Milpitas and Morgan Hill. Most of the outages were heat-related, said Jason King of Pacific Gas and Electric Tuesday evening. The utility said high power demand overloaded electrical equipment, and the prolonged extreme heat degraded its infrastructure.

Crews from PG&E worked overnight to restore power and got the number of customers affected down to about 3,585 as of 9 a.m. Wednesday, with more than 3,000 of those located in the South Bay.

CAISO acknowledged that a miscommunication led to the small number of power shutoffs. Two small local power companies — Alameda Municipal Power and Palo Alto Utilities — put in place rotating outages after 6 p.m. for about an hour, affecting several thousand customers.

The miscommunication occurred Tuesday afternoon as the grid was perilously close to running out of energy, Mainzer said at a briefing.

He said he did not know specifically how the miscommunication occurred, but he stressed the grid operator did not order rotating blackouts. CAISO had ordered utilities to prepare to institute load shedding but did not proceed to the final order to do so.

CAISO issued a Stage 3 emergency power alert Tuesday, one step below ordering utilities to start rotating outages to ease the strain on the system. The move allowed it to draw on emergency power sources.

Demand swelled in the late afternoon and into the evening, with everyone from Gov. Gavin Newsom to the state’s legal marijuana business control agency urging people to turn off lights and reduce power or use backup generators.

CAISO said the peak electricity demand on Tuesday hit 52,061 megawatts, far above the previous high of 50,270 megawatts set on July 24, 2006.

Demand fell toward evening as businesses closed, and dropped sharply after CAISO sent out a message on its mobile phone app begging customers to cut back their use, warning that “power interruptions may occur unless you take action.”

“Within moments we saw a significant amount of load reduction,” Mainzer said, adding that it took the state back from "the edge.”

The Stage 3 alert ended at 8 p.m. without major rotating outages. CAISO tweeted that “consumer conservation played a big part in protecting electric grid reliability.”

Western states, meanwhile, were still struggling through one of the hottest and longest September heat waves on record. Temperatures began soaring last week, and the National Weather Service warned that dangerous heat could continue through Friday.

Temperatures in many parts of the state soared to record highs. Six places in the San Francisco Bay Area and Central Coast set all-time record temperatures, including Santa Rosa with 115 degrees Fahrenheit, breaking a 109-year-old record. Sacramento broke a 97-year-old record, with a temperature of 116 degrees.

Sacramento native Debbie Chang was out walking in Capitol Park on Tuesday morning, pulling a wagon of Pop-Tarts and water to hand out to unhoused people. She lives in an old house that relies on wall-mounted cooling units that she says don’t work so well. The temperature reached 91 degrees in her house Monday night.

“The past few years in California, it’s really rough,” she said. “I really love this state. And growing up I never imagined I’d exactly want to live outside of California, unless maybe internationally. But this is very difficult.”

Sacramento County officials used the air-conditioned lobbies of some of their public buildings as cooling centers for people with nowhere else to go and offered free transportation for people who could not get there. Officials even handed out motel vouchers to some unhoused people through a program they normally reserve for the winter, according to county spokesperson Janna Haynes.

“While a lot of people can stay home, a lot of people do not have a home to stay in,” Haynes said.

In state office buildings, thermostats were being set at 85 degrees at 5 p.m. to conserve electricity.

In neighboring Nevada, Reno’s 106 degrees on Tuesday was its hottest day ever recorded in September, smashing the previous record for the date, which was 96 degrees in 1944. It came within 2 degrees of the all-time high for any day or month of 108 degrees, set in July 2002 and equaled in July 2007, according to the National Weather Service.

In Utah’s Salt Lake City — a city at more than 4,000 feet — temperatures were about 20 degrees higher than normal, hitting 105 on Tuesday, the hottest September day recorded going back to 1874.

Scientists say climate change has made the West warmer and drier over the last three decades and will continue to make weather more extreme and wildfires more frequent and destructive. In the last five years, California has experienced the largest and most destructive fires in state history.

A wildfire that started Friday in the Northern California community of Weed killed two people, and one that erupted Monday and spread rapidly in the Hemet area of Southern California also killed two people. Authorities said the people were found in the same area and apparently died while trying to flee the flames.

KQED's Dan Brekke and Katrin Snow contributed to this report.