LANSING (AP) – Michigan regulators have ordered the state’s biggest utilities to trim trees more aggressively, provide the state with more detailed explanations for major outages and make it easier for customers to get credits on utility bills when they suffer losses due to outages.

The orders follow a yearlong investigation by the Michigan Public Service Commission following last winter’s ice storm, the Detroit Free Press reported. The pre-Christmas storm knocked out or disrupted service to roughly 650,000 customers of Jackson-based CMS Energy Corp.’s Consumers Energy unit and Detroit-based DTE Energy Co.

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Scores of tree branches broke and fell from the weight of ice. A report released Thursday by the MPSC found that a large part of the storm damage was caused by falling limbs and trees – especially dead, brittle trees decimated by the invasive emerald ash borer.

Field investigators found that 40 percent of the tree-related outages triggered by the December ice storm were caused by trees growing outside of the utilities’ official right of way corridors. Next year, crews likely will take down far more limbs and trees than in previous years.

DTE already has become more aggressive about trimming trees, said spokesman Scott Simons. DTE recently launched the Ground to Sky program and shifted its decades-old practice of trimming branches within 10 feet of power lines to roughly 15 feet, Simons said.

“What we’re doing now is clearing a path from ground to sky, (removing) anything over the power line and anything under it that could grow up there,” he said.

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“And we also agree that some trees outside our easements need to come down, especially those dead ash trees that can be 60 feet tall. We want service reliability to be as close to 10 percent as possible.”

Following the report’s release, Consumers Energy said it is “always striving to improve our customers’ service experience,” according to spokesman Dan Bishop.

“Consumers Energy appreciates the comprehensive review by the Michigan Public Service Commission of our response, which it found satisfactory,” Bishop said in an email to the Free Press.

Both utilities also were ordered to revise their websites to prominently display electronic applications for customers requesting credits on their bills when they’ve had an outage. State rules for utilities allow customers who have lost power for a full five days to request a credit, but for no more than $25.

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