August 20, 2012

Trimming trees gets to the root of power outages

An aggressive program by CMP is beginning to generate positive results in keeping our lights on.

By Tux Turkel tturkel@mainetoday.com
Staff Writer

BRISTOL - Dennis Hopkins was waiting late last month at the stop sign at Walpole Meetinghouse Road, where he lives. Across Route 130, a worker from Asplundh Tree Expert Co. stood in a bucket high above the highway, pruning pine and maple branches away from the power lines.

click image to enlarge

Jason Perkins, at rear, and Patrick Gregory, both of Asplundh Tree Expert Co., trim trees along power lines in Bristol last month, as part of CMP’s five-year program.

John Patriquin/Staff Photographer

This was a welcome sight for Hopkins. The entire Pemaquid Peninsula, a rocky claw reaching south from Damariscotta into the Gulf of Maine, is served by a single electrical circuit. It connects small businesses along highways and summer cottages on dirt roads, via a 211-mile web of wire laced through the woodsy landscape.

The problem is, a stiff wind can turn out the lights for the 4,097 customers who live here, making the area one of the worst for electricity interruptions in Central Maine Power Co.'s service territory. Power went out 115 times in 2011.

"It's bad enough, that we invested in a generator," Hopkins said.

That generator may not get fired up as much in the future.

Falling trees and branches that touch overhead lines are the leading causes of power outages in Maine, the most heavily forested state in the country. In response, CMP is into the fourth year of a five-year maintenance program of aggressive tree pruning. Last year it trimmed back trees along 110,000 pole spans.

This effort is showing results, according to data filed with the Maine Public Utilities Commission. Stepped-up trimming, along with other measures, has begun to greatly reduce the number and duration of power interruptions for CMP's 607,000 customers.

The work is taking place during a period that has seen extreme weather in the Northeast topple trees and knock out power for days to millions of customers. Last August, it was Tropical Storm Irene; last October, the Halloween nor'easter; early last month, the violent storms that crippled cities from New Jersey to Virginia.

Late last month, environmental advocacy groups in Maine released a study contending that rain and snowstorms in New England are becoming more intense and more frequent.

No two storms are alike, and it's not possible, or desirable, to prune every tree near a power line. But the Maine PUC, which ordered the tree-trimming program in 2008 and oversees its progress, says CMP's local distribution system today is the most reliable it has ever been.

"Short of putting everything underground, which is prohibitively expensive, tree trimming is the best way to keep the wires humming," said Tom Welch, the PUC's chairman.

The tree program is part of the commission's alternative rate plan for CMP, which penalizes the company when it fails to meet performance standards that become stricter each year. The program costs ratepayers $22 million annually.

Next year, the rate plan is up for renewal. Welch and the other commissioners will review the tree program. And they will decide whether CMP's distribution system can or should be made even more reliable, and what that could cost.

Longtime Maine residents recall the impact of the 1998 ice storm, and may have come to accept the prolonged outages as unavoidable. But in fact, CMP's distribution system simply wasn't as dependable then.

A consultant hired by the PUC in 2007 noted that system reliability was poorer than average when compared against national utility indexes. It also found CMP's tree-related outage rate was among the highest in the industry, accounting for 42 percent of all power losses in 2005. At the time, CMP was trimming trees in a cycle ranging from seven to eight years.

This assessment helped form the basis for today's tree program.

Along Route 130, a worker armed with a brush saw moved up and down among the trees and wires in a 70-foot bucket. His assignment was to cut any branch within eight horizontal feet of a wire, and 15 feet above and below. It's a careful, methodical process, performed around live wires. On the ground, co-workers fed the downed limbs into a chipper.

(Continued on page 2)

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