Why Don’t More Communities Bury Power Lines?

Tuesday June 21, 2011
Posted at 08:14

Why don't electricity companies bury power lines more often?

In some parts of the country, communities bury their power lines. To many, it’s a safer and more aesthetic alternative to hammering poles into the ground and running exposed aerial wires in between. But in other parts of the country, like Houston, Texas, power lines are only buried in some of the newer communities, leaving much of the city draped in power lines. There are several reasons places like Houston don’t bury them.

Burying Power Lines is Expensive

Most new construction throughout the country uses underground utility lines. But going back and burying overhead power lines is usually cost prohibitive. While an above ground line might cost $20 a foot, an underground line can cost more than $400 per foot, according to Terry Finley, vice president of distribution engineering and services for CenterPoint Energy, Houston’s electric utility.

The Uptown Houston District, which was created in 1987 to oversee public improvements in the city’s Galleria area, has spent millions to move or bury power lines. John Breeding, president of the District, said projects to bury power lines in the Galleria area cost $500 to $750 per foot, or between $2.6 million and $4 million per mile. “You're not just burying the lines but the switches and transformers,” Breeding said. “So, something that you just attach to a pole up in the air becomes a $50,000 cost to put underground.”

CenterPoint spokesman Floy LeBlanc, who has worked with the District to beautify the Galleria area, said that the original estimate to bury all of the power lines in the area was $40 million. To help the District save money while addressing aesthetic concerns, CenterPoint found less expensive ways to move the power lines behind buildings, where they were less visible, rather than bury them.

Underground Outages Tend to Last Longer

Buried power lines tend to fail less frequently, but when they do, outages tend to last longer because it’s more difficult to locate the damage and repair it. In a 2003 study, Virginia electric utilities found that underground power lines stayed out of commission 2.25 times longer than above ground lines, with some outages lasting 7 times longer.

Benefits from Buried Power Lines are Inconclusive

In some areas of the country, like those that experience hurricanes, advocates for buried power lines say that underground lines are more protected and ultimately result in economic benefits because there are fewer outages from severe weather events.

However, this may not always be the case, especially if the high-voltage lines that feed the buried lines in communities and business districts are above ground. If those lines are buried, too, as many were in Houston’s Galleria area when Hurricane Ike blew through town, then electric service would more likely be preserved. However, damage to high voltage lines in areas where they are above ground would affect supply to the underground lines they feed, resulting in power outages anyway.

Mark Jamison is the director of the Public Utility Research Center at the University of Florida, an area of the country also subject to powerful hurricanes. He said that a cost-benefit analysis he and his colleagues developed showed that the benefits of burying power lines aren’t justified on a purely economic level.

“We couldn't find a situation where it was just economics alone that says you should do such a project,” Jamison said. “That's not to say such a case isn't out there. But you needed to take into account other factors, such as aesthetics, to justify the projects.”

Sources

You Can Bury Power Lines, but Not All the Problems,” The Houston Chronicle, Oct. 20, 2008.

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