Updated at 11:14 p.m. ET

Power is gradually being restored to tens of thousands of Californians after a second day of outages designed to mitigate the risks of wind-fueled wildfires.

The state's largest utility, Pacific Gas & Electric, restored power Thursday evening to about 228,000 customers, or about 30% of the estimated 738,000 customers who lost power. That still leaves about 510,000 customers without electricity.

"This is not how we want to serve you," said PG&E CEO Bill Johnson in a news conference Thursday evening. He apologized for the hardship the power outages caused, but said, "I do think we made the right call on safety."

The bankrupt utility had come under near universal criticism, including from Gov. Gavin Newsom who called the outages "unacceptable."

Johnson appeared to agree, adding his company failed to adequately communicate with its customers about the power shutoffs.

"Our website crashed several times, our maps are inconsistent, perhaps incorrect, our call centers were overloaded," he said. "Put it simply. we were not adequately prepared to support the operational event."

The day began with hundreds of thousands of Californians in the San Francisco Bay Area, Sierra Foothills and Humboldt County waking up without electricity.

Earlier, PG&E said the decision to cut power "was based on forecasts of dry, windy weather including potential fire risk" in California, which is currently at the peak of its wildfire season.

With winds gusting overnight, a 40-acre hillside blaze prompted evacuation orders for sections of the town of Moraga, about 15 miles east of Oakland, early Thursday morning. Those orders were later lifted, as firefighters contained the fire.

The National Weather Service in San Francisco issued a red flag warning Thursday for the hills and valleys in the North Bay and East Bay areas through 5 p.m. local Thursday.

The weather service forecast north to northeast winds with gusts up to 30 mph across some parts of the area. Forecasters said the wind, coupled with low humidity and dry terrain, would mean that "any fires that develop will likely spread rapidly" for much of Thursday.

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Transmission lines operated by PG&E have been linked to wildfires that have decimated several California communities.

PG&E has come under intense scrutiny for mismanaging sections of its power grid. It filed for Chapter 11 bankruptcy protection in January as it faced billions of dollars' worth of possible liabilities stemming from years of devastating fires in Northern California.

Since the outages began on Wednesday, the blackouts have sparked outrage among residents in the 34 affected counties. State Sen. Scott Wiener estimated that 2.5 million people could be impacted.

The second phase of PG&E's shut-off began late Wednesday. It was expected to impact roughly 234,000 customers, including people who live in East Bay, South Bay and Santa Cruz and residents of counties such as Alameda, Contra Costa and Santa Clara.

In the midst of confusion and frustration over the outages, there had been some positive news for PG&E customers. By late morning, the utility tweeted that restorations have begun in some areas and that 126,000 customers have their power back on.

The San Ramon Valley Fire Protection District tweeted late Thursday morning that the "vast majority of San Ramon" had their power restored.

When the first phase of blackouts began early Wednesday, it affected about 513,000 customers in counties such as Humboldt, Lake Marin and Sonoma, PG&E said.

PG&E has estimated that some 800,000 customers would have their power unplugged during the outage.

In the Moraga fire, an evacuation order was temporarily in effect for the Sanders Ranch section of the town of some 18,000 residents in Contra Costa County.

As member station KQED reports 140 structures were threatened:

The fire burned 40 acres and was 95% contained, according to Cal Fire. Evacuations ordered for the Sanders Ranch neighborhood overnight were lifted later in the morning. The cause of the fire has not been determined.

Steve Hill, public information officer for Contra Costa County Fire Protection District, told NPR that about 50 firefighters remained on the scene late Thursday morning local time to ensure the fire posed no longer posed a threat.

"We want to make sure there are no embers, nothing that could restart that fire," Hill said.

Another small fire — 11 acres — burned on the Brisbane side of San Bruno mountain in San Mateo County, just south of San Francisco, reports KQED which cited local officials. It was 60% contained.

It is still unclear how long some residents might have to live without power. PG&E said earlier that crews will have to inspect all electrical lines before restoring power.

It warned that customers could be without power for "longer than 48 hours" and suggests customers prepare themselves for an outage that "could last several days."

In California's wildfire season, the threat of fierce wind gusts and arid weather increases the chances of trees being toppled and falling into power lines — or of those lines being blown into dry vegetation and sparking a fire.

PG&E's preemptive power cut follows 2018's deadly Camp Fire in Butte County, a blaze that burned 14,000 properties and killed 86 people. A similar wildfire in California's wine country in 2017 killed 22 people and destroyed more than 36,000 acres. However in January, California fire investigators found a private electrical system, not PG&E, was responsible for the wine region blaze.

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