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State regulators granted San Diego Gas and Electric access to billions in taxpayer-supported wildfire insurance even though its plans to prevent these catastrophes has, in the minds of utility watchdogs, a fatal flaw.

The state Public Advocate’s Office last month sounded an alarm over SDG&E’s plan to trim or clear more than double the trees around power lines that California law recommends without providing credible science to back it up.

Utilities are spending hundreds of millions each year trimming trees so branches don’t come in contact with utility equipment. The deadly Rice Fire in 2007 was caused by a Sycamore branch falling on overhead SDG&E conductors igniting a huge brush fire. Regulators determined the utility violated regulations that govern permissible distance between electrically live cables, equipment and tree branches.

In June, the CPUC’s newly created Wildfire Safety Division agreed with utility watchdogs and marked SDG&E’s 25-foot tree clearance program a source of highest concern. Watchdogs thought that would put in jeopardy SDG&E’s chances of obtaining a safety certification, which grants utilities access to an over $20 billion pot of funding (paid by ratepayers and shareholders) that helps cover wildfire damage claims.

Not so.

Last week, the Wildfire Safety Division OK’d SDG&E’s plan under the condition that it justify its tree-clearing practices in the next one. The Public Advocate’s Office argues the utility should be sanctioned instead of rewarded with a stamp of approval because the division had already given SDG&E a year to prove their tree trimming strategy.

“There’s a lack of transparency,” said Nat Skinner, safety branch manager at the Public Advocate’s Office. “You ordered utilities to do their homework. We see that they passed, but we’re not seeing the work.”

SDG&E has “met all of the relevant requirements” of the state public utilities code, said Robert Iezza, a utility spokesman, in an email.

The utility countered that its tree-trimming plan is fine because CPUC regulations give recommended minimums for how far trees must be cut away so their branches or crowns don’t interfere with power lines. That minimum is 12 feet in high fire-risk areas.

When SDG&E trimmed its trees just two feet under the minimum, it saved the utility from 320 power line problems each year, according to an Aug. 17 letter from SDG&E to the Wildfire Safety Division. The utility wagers it also saved them from 27 fire sparking events, “an incredible reduction in risk,” the letter reads.

SDG&E wrote in another report that the 25-foot tree clearance is not intended to be applied to every tree. Of the 455,000 trees in SDG&E’s 2019 inventory, about 18 percent were flagged for 25-foot clearance or complete removal in high fire-risk zones. Tree trimming accounts for 6 percent of the $1.3 billion the utility plans to spend by 2022 on wildfire mitigation.

The Public Advocate’s Office experts worry that clearing away that much vegetation around a utility pole could backfire ecologically, allowing taller non-native grasses to grow around a pole and turn the area into a different kind of tinderbox.

The utility says that native shrubs and bushes aren’t at risk of being cleared because they’re well below 25 feet of reaching the top of a 40- to 50-foot power line pole.

And, according to SDG&E’s own data on what starts a spark along their equipment, vegetation (or tree) contact caused zero problems between 2017 and 2019. Balloons, on the other hand, caused 20 sparks over that same time period. The landscape is different for a utility like Pacific Gas and Electric serving customers in forested Northern California. Contact with vegetation caused over 50 percent of the sparks along PG&E’s equipment between 2014 and 2016.

There are other problems with SDG&E’s plan. Sixteen, to be exact.

For instance, regulators questioned SDG&E’s classification of risky wildfire tree species. The utility labels eucalyptus, palm, oak, pine and sycamore as riskier trees in terms of fueling wildfires. But the Wildfire Safety Division noted not all trees within those species are truly riskier.

Now SDG&E will have to explain what properties and characteristics of a tree it considers when labeling it risky.

California’s other big investor-owned utilities – Pacific Gas and Electric and Southern California Edison included – have different rules for how they decide to cut a tree away from a power line. In light of this discovery through the safety certification process, the CPUC ordered the three to get together and figure out best practices.

Lindsey Purcell, a master arborist and urban forestry expert at Purdue University, said the amount of tree clearing should be commensurate with the amount of power that runs through the line. In other words, higher powered lines, like big transmission lines that generally run through backcountry areas, should be further from fire fuel.

“Every forester will tell you that fire is a necessary component of any kind of ecosystem management,” Purcell said. “The reason we have so many wildfires is because we’re not allowed to do controlled burns anymore.”

That’s mainly because home-building and development has moved increasingly into rural, wilder areas, he said. Controlled burns eliminate fuel for potential wildfires in a managed way.

“The increasing rate of wildfires is pretty new and the research behind it is gaining momentum,” Purcell said. “But we’re still learning a lot about the impact of fires on an ecosystem related to utility lines.”

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