The thunderstorm that roared through Southern Maryland last Friday night toppled trees and utility poles, knocking out electricity to 61,745 of Southern Maryland Electric Cooperative’s 153,000 customers.
Only a smattering of customers were still without power at 12:20 p.m. Thursday: five in Charles County and three elsewhere in the region.
Last August, Hurricane Irene cut off power to 108,000 of SMECO’s customers, the most in the electric cooperative’s 75-year history. The damage cost SMECO $7.5 million to repair, of which $5.5 million was federally reimbursed, Dennison said.
Despite the huge disruptions to service and the cost of making repairs, burying all electric lines to keep tree limbs from falling on them in severe weather is not a feasible option, a SMECO spokesman said this week.
SMECO, which serves southern Prince George’s, and all of Calvert, Charles and St. Mary’s counties, has 10,423 miles of distribution lines, of which 6,847 miles is buried underground, said Tom Dennison of SMECO. “We have a lot of underground distribution already,” he said.
A state law was passed in the 1970s that required electrical utilities be buried underground for new housing subdivisions, but there are still numerous neighborhoods in Southern Maryland that are older than that with overhead lines.
There are three main reasons why SMECO does not bury more lines underground, Dennison said — cost, reliability and the environment.
On average, there are 14 SMECO customers per mile of electrical line, Dennison said, far less dense than utilities in more populated areas.
State studies indicate that the cost to bury electrical lines throughout Maryland would easily exceed $1 billion.
Dennison did not have a figure on how much it would cost to bury all of SMECO’s lines, but he said that a study in Calvert County showed it would cost 13 times more to put lines under the ground in a particular neighborhood.
“The costs become massively prohibitive to the point where we would have a very difficult time gaining regulatory approval,” Dennison said.
SMECO customers could see their bills increase by $200 to $400 a month to cover the cost of burying lines, he said.
“As an electric cooperative, we’re constantly trying to deliver the highest quality and best reliable service at the lowest possible cost,” Dennison said.
Then too, a buried electrical line versus an overhead line is much more difficult to repair. For underground lines, “we have a lot of difficult repairs that take a much longer amount of time. Instead of minutes, these are hours and hours,” Dennison said. A break in a buried line has to be located, dug up, spliced and tested, he said.
While overhead lines are subject to high winds and falling trees, underground lines are more susceptible to heat, water and being cut accidentally by digging, and can still be zapped by lightning, he said.
In gaining environmental permits for utilities, overhead lines are preferable to underground trenching, Dennison said. State and federal agencies would rather see a single ground disturbance for a power pole than a long line of trench to bury lines, especially in sensitive areas like wetlands.
A state of emergency was declared in Maryland after last Friday’s “derecho” thunderstorms as well, so there may be reimbursement again, though the damage to SMECO’s system is still being tallied.
Del. John F. Wood (D-St. Mary’s, Charles) said he lost power for only an hour and a half after the thunderstorm at his Mechanicsville home. “We were very lucky in Southern Maryland with SMECO,” he said Thursday. “They do a great, great job. These guys, they work to get us back online as quick as possible,” he said.
Other utilities bury their lines, but “they still have problems,” Wood said.
Staff writer Erica Mitrano contributed reporting to this article.
jbabcock@somdnews.com