How decades of neglect left Detroit’s grid vulnerable to powerful storms

  • Sep 17, 2021
  • Electric Light & Power

Art Reyes and his family faced an increasingly common summer plight in metro Detroit last month after a thunderstorm knocked out their electricity.

He and his wife and newborn scrambled for a place to stay — and to store the supply of bottled breast milk at risk of going bad in their thawing freezer. They ended up relocating to a relative’s house an hour away for five days before DTE Energy finally restored power at their home.

Michigan has among the country’s least reliable electric grids, consistently ranking in the bottom quarter for the frequency and length of outages. While DTE recently blamed Michigan’s growing grid problems on the state’s wealth of “beautiful trees” hitting lines, industry experts and stakeholders say the company and regulators are responsible. Decades of inadequate tree trimming and a failure to replace aging equipment, they say, have left the grid vulnerable to strong storms that are increasingly frequent as the climate changes.

“The grid in the older parts of DTE’s service area is weaker and less able to avoid outages when there are storms,” said Douglas Jester, a consultant with 5 Lakes Energy who intervenes in utilities’ regulatory cases. “And a significant part of the reliability of an overhead distribution grid is tree trimming.”

It’s more than just an inconvenience to customers. The Reyes family concluded their ordeal by emptying spoiled food from a fridge and spending hundreds of dollars to restock it. Across the region, tens of thousands of residents faced similar expenses as they went without power for over a week.

“Nobody should have to go through an extended period of time without consistent and stable access to heat, lights and electricity,” Reyes said.

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DTE Energy, formerly Detroit Edison, previously cut branches around segments of distribution lines every nine years, while the industry standard was about five years. It also only trimmed branches within a few feet of lines instead of all that threatened its wires.

That has left especially fragile equipment exposed to a high number of branches or trees. On average, Michigan sees about three times more outages per customer and it takes about three times longer to restore electricity after a storm than in Minnesota, a state with a similarly leafy landscape, according to federal data. Xcel Energy, Minnesota’s largest utility, operates on a three- to five-year trim cycle.

The silver maple, among the most common trees in southeastern Michigan, can sprout up to six feet of new growth annually. That means they were capable of growing 54 feet between the company’s nine-year trimmings. Meanwhile, DTE didn’t trim dead or diseased trees that threatened power lines but weren’t in its right of way, as other utilities often do, Jester said.

“They were going with a fairly long trimming cycle, and their trimming standards were modest,” he said. He noted that part of the lax trimming policy resulted from property owners’ resistance to having their trees cut. “It was partly that, and, it seemed, a loss of attention to the issue,” he added.

DTE likely resisted robust tree trimming because the company makes money for shareholders by building major infrastructure like power plants, not by performing preventive maintenance, said Amy Bandyk, executive director of Citizens Utility Board of Michigan.

“That’s probably one of the reasons why routine-but-important stuff for maintaining reliability tends to fall by the wayside,” she added.

Regulators also felt less urgency around the issues during the 1990s and early 2000s because fewer powerful storms hit the region, and Detroit Edison claimed to have a handle on the situation, said Bob Nelson, who served as a commissioner with the Michigan Public Services Commission from 1999 to 2005.

Regulators at the time only “nudged” the company on tree trimming and replacing old equipment, which “clearly wasn’t enough,” he added.

“Michigan now ranks toward the bottom in how long it takes to restore power, but that wasn’t the case in the 1990s,” he added.

Outages worsened in the 2000s, and, at local politicians’ behest, DTE took over Detroit’s struggling utility department’s territory around downtown in 2013, adding to the company’s troubles.

By 2010, the Public Services Commission had required DTE to start providing more outage data, and the company “promised to do better,” Jester said. But it didn’t, he added, and the commission didn’t order meaningful action until around 2015.

DTE defended its policies in a statement, noting that it has been more “aggressive” with its tree-trimming policies in recent years following pressure from regulators. It also has in place equipment replacement cycles that it is “constantly tensioning,” said DTE spokesperson Peter Ternes.

DTE is moving toward a five-year trim cycle, cutting all branches above its lines instead of those within five feet, and cutting dead trees that could damage lines, even if they stand outside the company’s right of way. As part of its new “tree trimming surge,” DTE is aiming to cut all branches and trees threatening lines across its service area by 2025. However, the effort has been slow to ramp up because the company didn’t have enough employees, Jester said.

Still, DTE has touted its progress, noting that it cut trees along over 5,500 miles of distribution lines in 2020.

The cost of catching up on tree trimming has fallen on customers, and partly explains why DTE’s service territory has experienced some of the nation’s highest rate increases in recent years. That issue speaks to the company’s investor-owned model, said Reyes, who works with We The People, a group that advocates for low-income residents.

“When a utility is driven by a profit motive and not driven by making sure people have stable access to energy, then these things are going to happen more frequently,” he said.

Another factor in the region’s reliability problems is DTE’s “replace it when it breaks” approach to upgrading old equipment in and around Detroit, Jester said. Some equipment has aged decades beyond its expected life. Poles have grown brittle and are now more likely to break when stressed by wind. Wires that were damaged in previous storms were often patched instead of replaced, Jester said, leaving them weakened. And while wires can function well beyond their expected lives, they become more vulnerable to lightning as insulation wears off.

Meanwhile, overcurrents can cause the grid’s aging fuse cutouts and reclosers, which function similarly to circuit breakers, to fail. DTE’s service territory also sees problems with its old pole tops, or crossbars at the top of a pole, which hold insulators that separate the wires from the wood, Jester said. Aging insulators deteriorate and crossbars weaken, which increases the likelihood of breakage should the line be jerked by a falling tree or wind.

“We have a lot of old equipment and it’s in need of faster replacement,” Jester added.

Experts say several issues and DTE policies are behind the grid’s age. During the 1990s, Edison told the Public Services Commission that “they had things under control and they didn’t need to update infrastructure,” Nelson said.

“White flight” also contributed to the problem. As population increases in a city or region, utilities are incentivized to replace equipment so grids can handle the increased electricity demand.

In Detroit, the opposite has occurred. The population declined for decades as residents moved to the suburbs, disincentivizing equipment replacement. Without that economic incentive, Jester said, DTE has taken a “purely reactive” approach.

“They would fix things when they break and that’s not unreasonable up to a point, but as equipment ages, breakage happens more frequently, and it eventually becomes effective to replace things simply on condition,” he added.

Meanwhile, a 1974 state law required new distribution infrastructure to largely be built underground, which protects it from storms. Experts say evidence suggests a clear disparity in how older and newer regions of DTE’s system fare during storms, and the 1974 law and aging infrastructure are driving it.

The Public Services Commission didn’t seriously challenge DTE on its aging equipment until outages became more of an issue around 2010, Jester said, and the agency didn’t start pushing for more infrastructure upgrades until around 2014. In the August storms’ wake, the commission has asked utilities for even more detailed information on companies’ equipment, those components’ roles in the outages and where in its grid outages are occurring.

Still, experts say DTE is “in a hole” that could take years to dig out of. Reyes called on the company to stop spending money on political contributions, executive bonuses and other measures that don’t improve reliability.

“I would hope that they would start focusing on ensuring that their service is reliable and that we stop seeing the incredible amount of money that they pump into our politics to protect them from having to change,” he said.

Tom Perkins is a freelance reporter based in Detroit.

This article first appeared on Energy News Network and is republished here under a Creative Commons license.