Why Aren’t All Power Lines Underground?

Power lines
Adobe Stock Photo by Naya Na

The massive storm that rolled through Bullhead City over the Labor Day holiday weekend knocked over or damaged more than 140 poles in MEC’s service territory and prompted many members to ask about burying the electrical lines rather than running them through the air.

The misconception is that buried lines aren’t susceptible to Bullhead City winds, but while MEC uses the existing utility rights-of-way, there is more to it than just the existing path and the wind.

The LA Times recently ran a story discussing the costs associated with burying aerial electrical lines. A representative of GridLab, a nonprofit focused on power grid transformation, estimated that to bury just 10% of the lines in the California electric utility’s service territory would cost at least $15 billion. While costs to bury existing overhead lines are expensive, there are other factors to consider. Both buried and overhead lines each have pros and cons to them.

“While there are advantages to burying lines, there are negatives to it as well,” said Jerry Hardy, MEC Manager of Engineering/Operations. “For the storm damaged poles, we are tasked to restore damaged infrastructure to its pre-storm damaged condition, whether they were aerial or buried. But to try to bury all the existing lines would not be cost effective.”

Hardy said that the cost to run lines underground is roughly four times that of running them aerial. MEC currently has 1,569 miles of electrical lines in place. Of that, more than 1,078 miles are overhead

The Pros & Cons of Overhead & Underground Power Lines

Overhead

Pros:

  • Less expensive to build and repair
  • Easier to spot faults/damage
  • Can be built on any terrain

Cons:

  • Susceptible to wind, ice and snow
  • More vulnerable to damage from trees and vegetation
  • More vulnerable to momentary outages caused by animals
  • Susceptible to damage from vehicle collisions

Underground

Pros:

  • Not impacted by trees, wind, ice and snow
  • Less vulnerable to momentary outages caused by animals

Cons:

  • More expensive to build and repair
  • Susceptible to flooding
  • Difficult to locate faults/damage
  • Vulnerable to damage from digging