After years and billions of dollars spent on insulating above-ground wires to reduce fire ignition risk, Southern California Edison is now stepping up its efforts to underground wires in high-risk fire zones.

In the near term, Southern California Edison, a subsidiary of Rosemead-based Edison International, is planning to place roughly 120 miles of power lines underground in the Eaton and Palisades burn zones, spurred in part by Gov. Gavin Newsom’s recent executive order waiving some permitting requirements.

And an Edison spokesman confirmed that up to 1,000 more miles of power lines could be placed underground over the next three years.

Earlier focus on insulating power lines

This is a marked shift from Edison’s recent history in which the utility was primarily focused on insulating its above-ground wires in fire zones, proclaiming that strategy was both faster and cheaper than undergrounding.

Since Edison launched its wire insulation program in 2019 in the aftermath of the catastrophic Thomas and Woolsey fires of 2017 and 2018, it has spent roughly $5.4 billion to install 6,400 miles of the insulating material – known as covered conductor – on its wires, which translates to a cost of $840,000 per mile. That contrasts with the average cost to underground one mile of power line wire of about $3.8 million, or more than four times as much.

“Covered conductor is a critical tool to quickly mitigate the threat of wildfires that could be caused by debris blowing into power lines,” Southern California Edison Chief Executive Steven Powell said of the program back in 2022.

With the announced covered conductor installation program now about 90% complete, Edison has touted the fact that none of its lines with covered conductor material has sparked a wildfire.

Gradual approach to undergrounding until recently

Southern California Edison has for decades been gradually placing more of its 16,700 miles of distribution wires underground. Up through the end of last year, about 7,400 miles of wires were underground, including the entire city of Bevely Hills.

But only a small portion of that total – about 38 miles – has occurred in areas at high risk for wildfires since 2021, compared with 6,400 miles in high-risk fire zones that have had covered conductor insulation material applied since 2019.

Edison spokesman Jeff Monford suggested several reasons for this. First and foremost is the aforementioned much higher cost. But there are also issues with terrain: it’s much harder to do the trenchwork and install underground vaults in sloped areas that pose the highest fire ignition risk.

The concrete vaults can vary in size, but average about 14 feet long by 8 feet wide and 9 feet high; they must be buried completely underground. The vaults house power line conduits, transformers and other equipment; they are also the access points for crews to get to the underground lines. In between the vaults, trenches must be dug to allow for the power lines to run through at a depth of up to 4 feet below the surface.

Prior to Newsom’s executive order, getting all the easements and permits for an underground project could take a year or more. Each mile of underground power lines interspersed with vaults can take several months to construct.

Despite this time and expense, in the aftermath of January’s Eaton and Palisades fires, calls have mounted from local residents and other advocates for all utility wires to be undergrounded in high-risk fire zones. Underground wires have almost zero chance of igniting in a way that can spark massive wildfires.

“Undergrounding may cost more upfront, but our model shows it would save Californians tens of billions over the coming decade by preventing catastrophic wildfires altogether,” said Mark Falzone, president of Washington D.C.-based Scenic America, which advocates for billboard and above-ground power line removal.

Edison steps up undergrounding

These calls have prompted Southern California Edison to step up its undergrounding efforts, starting with areas of its territory burned in the Altadena and Palisades fires.

Late last month, Newsom issued an executive order to suspend many of the permitting and review requirements for putting underground utility wires damaged or destroyed in fires. The aim is to reduce the time and expense associated with undergrounding.

Edison welcomed the move.

“The emergency declaration gives cities, counties, and other agencies an opportunity to expedite siting and permitting which can speed up the construction timeline,” Edison spokesman Jeff Monford said. “In addition, it is more cost-effective and likely less disruptive to do this work now, and rebuild with the community,” than having to take wires underground in a built-up community. 

Monford said Southern California Edison is now planning 80 miles of underground wires in the Palisades burn zone (primarily in the Malibu area) and about 40 miles in the Altadena burn zone, starting in locations closest to Eaton Canyon.

He added that through 2028, Southern California Edison is planning to underground “less than 1,000 miles” of wires in high-risk fire zones as part of the utility’s wildfire mitigation strategy. How many miles would depend on the utility’s technical evaluations and how much ratepayer money the California Public Utilities Commission authorizes for the effort.

Monford said the utility is not considering moving underground any of the wires that have already been hardened with covered conductor material.

Push for more underground wires

Scenic America’s Falzone welcomed this shift in approach.

“Too often, utilities have rebuilt above-ground infrastructure after fires, citing cost and speed as justification,” Falzone said. “But these choices have repeatedly exposed Californians to more risk, more destruction, and more preventable costs. It’s time to stop applying short-term fixes to a long-term problem. Rebuilding above ground – especially in high-risk fire zones – is a failure of foresight and public responsibility.”

Falzone said that while Scenic America isn’t calling for the lines already hardened with covered conductor to be moved underground immediately, he viewed the covered conductor approach as an “intermediate step,” with the ultimate goal of undergrounding all wires in high-risk fire zones.

Meanwhile, state Sen. Suzette Valladares, R-Santa Clarita, last month introduced legislation to exempt all underground wire projects from certain provisions of the California Environmental Quality Act.

“The governor’s action is a step in the right direction, but it doesn’t go far enough,” Valladares said in introducing her bill. “The wildfire risk posed by overhead power lines isn’t limited to just one region – it’s a statewide crisis. If streamlining the process for undergrounding power lines is necessary to protect communities already ravaged by fire, then it’s necessary to protect all Californians by preventing the next potentially devastating disaster.”

Undergrounding has its own problems

Edison’s Monford cautioned that even with the state’s waiving of some permitting requirements, there are still plenty of problems to overcome with undergrounding, especially once the effort moves beyond the burn zones.

“Getting the easements can be a very time-consuming process and requires community cooperation,” he said.

Also, in some instances, individual electric meters may have to be relocated or reconfigured.

“That’s why it’s so much easier within the burn zones when you’re building from the ground up along with the rest of the community,” he said.

Once underground lines are installed, the main ongoing problem will be difficulty of access, both for routine maintenance and for power outages.

Monford noted that an outage that might take two or three hours to fix above-ground can take several more hours or even days to repair when the wires are underground.

Also, in rare instances, fires can occur in the underground vaults that house the transformers and other electrical equipment. When those fires do occur, they are notoriously difficult to put out. Often water cannot be used due to the high risk of explosion; instead, carbon-dioxide gas might need to be pumped in to take away the oxygen fuel.

Yet despite all these potential pitfalls, Monford said Edison is committed to the undergrounding effort.

“We are working to identify additional locations for undergrounding,” he said. “We are focused on high fire risk areas to reduce the threat of ignition and increase the reliability of our systems.”