California power lines spark wildfires and prompt blackouts. Why not just bury them?

Janet Wilson, Palm Springs Desert Sun
,USA TODAY•October 12, 2019

•••••

It costs about $3 million per mile to convert underground electric distribution lines from overhead, while the cost to build a mile of new overhead line is less than a third of that, at approximately $800,000 per mile, according to a section on PG&E's website called Facts About Undergrounding Power Lines.

•••••

PG&E, the state's largest utility, maintains approximately 81,000 miles of overhead distribution lines and approximately 26,000 miles of underground distribution lines. It also has about 18,000 miles of larger transmission lines, the majority of which are overhead lines.

At a cost of $3 million per mile, undergrounding 81,000 miles of distribution lines would cost $243 billion. PG&E has 16 million customers; distributing that expense equally would amount to a bill of more than $15,000 per account.

•••••

Environmental concerns would also be high if thousands of miles of trenches were dug through forests or brushland habitat, Borenstein noted. Opposition could also arise from residents in existing neighborhoods confronted with the prospect of heavy-duty earth-moving projects.

•••••

But Borenstein and others noted that problems can occur underground as well. Animals can chew buried lines or lightning can short out ground connections, just as animals can damage lines overhead, or a dry tree branch can drop. The state's extremely varied landscapes are another challenge.

•••••

Borenstein agreed that vegetation management and hardening transmission and distribution lines are better, more easily implemented alternatives than burying 100,000 miles of lines.

"That means mowing, cutting trees, perhaps replacing wooden poles with concrete poles, and all the rusted transmission towers," he said. "They're trying to do these things, but they have a huge backlog of work."

Other possible measures include insulating exposed lines or installing sensors, including cameras or devices that can detect a spark or a short and even shut down a line automatically.

•••••