The widespread destruction of utility lines during Hurricane Ida is only the latest in decades worth of such damage. But as the nation, has become more dependent on electricity, it’s likely that the discussion of greater protection of the grid will increase.
A story last week on The Washington Post website carried the headline, “What it would take to put all our electric lines underground.” The main thing it would take is a lot of money, which means sharply higher rates for customers. Which means a great move below the ground is unlikely.
Some heavily populated areas have had underground electric lines for a long time. Manhattan is the best example, one of many urban areas to use that method of distribution.
But any utility, state or city considering a similar move on a far grander scale should be prepared for a gigantic pricetag.
The Post reported that Pacific Gas & Electric, a major utility in California, has for years resisted calls to bury its transmission lines because of the expense. But after the company’s electric lines got blamed for starting several forest fires, it decided in July that it will put 10,000 miles of overhead wires underground.
The estimated cost is $15 billion to $30 billion. That translates to a projected cost of $1.5 million to $3 million per mile.
Utilities in Virginia and Wisconsin also are planning to bury about 5,000 miles of lines. The estimated cost is $2 billion apiece, or a comparatively cheap $400,000 per mile.
As for the idea of putting the country’s entire electric grid underground, that involves 160,000 miles of high-voltage transmission lines and a whopping 5.5 million miles of local distribution lines. Based on the California, Virginia and Wisconsin estimates, the numbers say that a widespread switch to underground lines is unlikely any time soon.
In fact, an underground network carries its own set of potential problems.
Getting at underground electric lines for repairs or maintenance can be a challenge. Electric lines naturally heat up as they carry current, so they would need a system to keep them cool in an enclosed space below the surface. This obviously is a problem that cities have solved.
And while underground lines are not susceptible to harm from the high winds of a hurricane, the network must be watertight to prevent flooding from causing damage.
There are two other things that utilities can do at a lower cost to provide more security for the existing system of overhead electric lines.
One is better anchoring of utility poles. Part of the problem in Louisiana was that Hurricane Ida’s heavy rain arrived when the ground was already saturated. This caused some poles to sag and automatically shut down their lines.
But the most obvious task is to significantly widen the area beside utility poles where trees are kept out. In some places, especially in rural areas, trees or branches are allowed to grow within 15 feet of a line. This ought to be expanded to 30 to 40 feet on each side of utility lines.
This wider distance is certain to greatly reduce the number of trees or large branches that fall onto the lines during bad weather.
This would create controversy, and it would be expensive to widen the right of way. Residents of municipal areas would lose a lot of large shade trees that are too close to power lines, and rural landowners would lose more square footage where they could grow timber.
But if electricity is a priority, it should be treated that way. A hurricane’s winds are going to cause enough damage to power lines on their own. Sturdier, braced poles along with wider cleared areas could prevent storm damage from being worse, and could get the lights back on more quickly.