Lodi News-Sentinel

California beginning to bury its power lines to prevent wildfire

- Lisa M. Krieger

WALNUT CREEK, California – Etched in dirt, a narrow furrow is the only clue that the grasslands of Lime Ridge Open Space will soon be restored to their original splendor, cleared of dangerous power lines that could ignite nearby subdivisio­ns.

The undergroun­ding project, costing $3.75 million a mile, represents the beginning of a 10,000-milelong effort by Pacific Gas and Electric to bury the state’s distributi­on lines to cope with the growing risk of winds and wildfires linked to global warming.

“It is a one-time investment to eliminate essentiall­y all ignition risk related to power lines, with the added benefit of reducing reliabilit­y issues,” said Jamie Martin, who oversees PG&E’s undergroun­ding initiative. “It’s permanent risk reduction.”

The utility long resisted calls to bury its power lines as being too costly.

But after its equipment was blamed for sparking a string of devastatin­g wildfires in Northern California the past few years that have killed dozens of people and destroyed thousands of homes, the company reversed its position. It filed for bankruptcy protection in 2019 after facing $30 billion in wildfire-related fines and liability, and pleaded guilty to 84 counts of involuntar­y manslaught­er in the 2018 Camp Fire that destroyed the town of Paradise.

Other fire-prone areas of the Bay Area are also targeted for undergroun­ding. Based on an analysis of weather patterns, fire history, tree density, outage data and other factors, priority is going to parts of Santa Rosa, Rossmoor, Pacifica, West Marin’s Lucas Valley and the coastal towns of Pescadero and Davenport.

Only 175 miles will be buried this year — but the project will accelerate. PG&E, the nation’s largest electricit­y provider, has estimated about 3,600 miles will be completed from 2022 to 2026. When all 10,000 miles are undergroun­d, risk will be reduced 70% to 80% in high fire-threat districts, said Martin.

But it’s also a very expensive approach.

“We’re not convinced that undergroun­ding offers the greatest reduction for the most effective cost,” said Mark Toney, executive director of TURN, The Utility Reform Network. “And that’s really important, because we’re in an affordabil­ity crisis, when it comes to monthly electricit­y bills. We want PG&E to look at other options. We’re skeptical that ratepayers will end up getting their money’s worth.”

But stopgap measures, such as Public Safety Power Shutoffs during windy days, have proven disruptive, abruptly cutting off power to tech-dependent communitie­s. Tree-trimming demands constant effort. Meanwhile, burying wires and cables is getting cheaper and easier. With innovation­s in tools and techniques, the utility expects that the cost will drop to $2.5 million a mile by 2026.

“PG&E is being very smart in doing this. It’s a great move,” said Samuel Ariaratnam, constructi­on engineerin­g program chair at Arizona State University.

It’s a trend all over the United States as a changing climate sparks severe weather patterns.

“This is not just a California problem. This is a national problem,” said geotechnic­al engineer Brian Dorward of Brierley Associates. “California has wildfires. Florida has hurricanes. The Midwest has tornadoes. All natural disasters play havoc on power lines, which are critical infrastruc­ture.”

But none have proposed a project on the scale of PG&E’s new plan. San Diego Gas & Electric, a smaller utility, has buried 44% of its distributi­on lines and 4.4% of its transmissi­on lines. In cities such as Manhattan, lines have been channeled undergroun­d for years. cq comment=”; now, there’s a proposed undergroun­d line to stretches all the way from that city to Toronto. Germany and the Netherland­s are moving to put all their lines undergroun­d” ].

Compared to elsewhere, PG&E has been slow to embrace the solution, said Robert McCullough, a veteran energy consultant in Portland, Oregon, and adjunct professor of economics at Portland State University.

“California is the nation’s most regulated state, with a certain amount of inertia. It’s rigid and slow to respond,” he said. “But Pacific Gas & Electric is the poster child of rigidity. … It should have been fixing everything all the time.”

In the East Bay, the new undergroun­d route across the windswept chaparral of Lime Ridge will link Ygnacio Valley subdivisio­ns in Walnut Creek and Concord. Once it is finished, tall distributi­on towers will come down.

The installati­on method is straightfo­rward in the region’s soft sedimentar­y soil. A bulldozer with a plowing blade digs the furrows. Twelve-kilowatt lines are buried almost three feet undergroun­d, deep enough to prevent damage from erosion or animals. The lines, only 1-1/2 inches wide, sit inside a 6-inch black PVC conduit, so there’s space for ventilatio­n. A second empty conduit, which serves as a spare, sits alongside.

Then work crews quickly cover it with dirt, and dampen it. Sometimes they reopen an area to check the integrity and depth of the conduit.

The process is not always so simple in areas where other utilities — gas, cable, fiber-optic — are also undergroun­d. That requires open trenching, a slower and more traditiona­l approach with much more hands-on manpower.

But new tools are accelerati­ng the work. A powerful device called a “rock wheel” can cut clean rock walls with a sharp rotary blade. Another, called an “asphalt zipper,” can open up a 1,000foot-long stretch of road in merely an hour; using backhoes and jackhammer­s, it takes days.

If drilling must be deep or if a line must run under a river or a road, a technique called horizontal directiona­l drilling is a better option, said Ariaratnam. Rather than trenching, it uses a machine to drill a precisely-guided pilot hole and then pulls a conduit, holding the cable, through the hole. While more expensive than open trenching, it greatly reduces the time and effort spent on restoratio­n.

For now, PG&E’s program is focused on burying distributi­on lines which are closer to homes, rather than the large high-voltage transmissi­on lines, said spokespers­on Jennifer Robison. The transmissi­on lines conduct more heat, so they must be housed in big concrete ducts, she said.

While welcoming the effort, McCullough and others urged greater speed and expansion.

“We are at the start of global warming, not the end,” he said. “We’re going to be seeing increased average temperatur­es and wind speeds for years to come.”

 ?? ANDA CHU/BAY AREA NEWS GROUP/TNS ?? Tyler Owens, left, directs track hoe operator Alan King, both with the Undergroun­d Electric Constructi­on Company, as they work to dig two lines of 6-inch conduit to the correct depth at the Lime Ridge Open Space in Walnut Creek on Thursday, May 19,
ANDA CHU/BAY AREA NEWS GROUP/TNS Tyler Owens, left, directs track hoe operator Alan King, both with the Undergroun­d Electric Constructi­on Company, as they work to dig two lines of 6-inch conduit to the correct depth at the Lime Ridge Open Space in Walnut Creek on Thursday, May 19,

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