Answering the dreams of storm-darkened homeowners across the Carolinas, Duke Energy will test burying overhead power lines.
The N.C. Utilities Commission last month gave Duke permission to team up with three communities, not yet named, to assess the feasibility of larger-scale conversions.
Massive costs limit replacing power lines strung from utility poles with wires snaking underground on a broad scale. It would cost $41 billion and take 25 years to replace existing lines statewide, commission staff has estimated.
But limb-cracking ice storms and power losses – such as the one that shut down power to 1.3 million customers from Missouri to West Virginia this week – have a way of focusing interest on the concept.
After a 2005 ice storm left parts of Greenville, S.C., without electricity for up to a week, residents clamored for buried lines. The city is now mulling whether to spend $12.5 million over a decade to bury 30 miles of Duke's lines.
For all its ambition, Greenville's plan would cover only a fraction of the city's lines – doing them all would cost $500 million, five times the city budget, said assistant budget director Jim Campbell. Customers would bear the costs.
Going underground is also complicated, Greenville has learned. Roads and sidewalks have to be dug up, broken sewer lines fixed, provisions made for the telephone and cable TV lines that share utility poles.
“We've been at pains to tell citizens that even if we do this, we can't guarantee the power can't go out,” Campbell said. While they're safe from ice and wind, buried lines can fail for other reasons.
A 2002 ice storm that hammered Charlotte cracked branches, uprooted trees and ripped down power lines, leaving some residents without power for more than a week The event prompted a study by the Utilities Commission's Public Staff. The study estimated the cost of going underground at up to $3 million a mile, compared to $120,000 a mile for pole-mounted lines.
Duke, under its recently approved N.C. plan, would match local money for limited tests of burying high-maintenance or hard-to-reach power lines. The utility would spend up to $1.5 million a year over the three-year tests.
“These are targeted situations where we think there could be a benefit,” spokesman Andy Thompson said.
Charlotte officials say they don't yet know whether the city will take part, although Durham has expressed early interest. Duke is also offering similar partnerships in South Carolina, but no agreements have been signed.
Because Duke routinely buries lines at new residential developments, 23 percent of its distribution lines – such as those found along streets – are already underground.
Two other Carolinas utilities, Raleigh-based Progress Energy and S.C. Electric & Gas, report 30 percent and 23 percent of their lines underground, respectively.
Duke spends $40 million a year on trimming trees away from its lines, but still experienced 65,000 outages – affecting a single household to thousands of people – in the Carolinas last year.
Tree-trimming itself can cause its own heartaches.
When Duke planned to clear trees along an overhead transmission line behind their Charlotte home last summer, Bruce and Karen Bezanson fought back. “They had the whole neighborhood up in arms,” Bruce Bezanson said.
After the intervention of a state official and Rep. Sue Myrick's office, Duke and the couple compromised, sparing a few trees.
“I understand ice storms and all that, and I don't want anyone losing power because of my trees,” Bezanson said, “but the trees they cut were not going to come down on any lines.
“Put them underground and you eliminate 90 percent of the problem.”