Jul 23, 2025
Burying Transmission vs. Distribution Lines: Key Differences
Burying power transmission lines has been a touchy subject for years. Utilities tend to resist underground transmission because it is costly and not enough is known about its potential environmental impacts. On the other hand, burying transmission lines is fairly common. It has been a practice in the U.S. for decades.
So what is the difference? Primarily voltage. Transmission lines are high voltage lines capable of carrying up to 765 kV. Distribution lines are low voltage lines that typically service neighborhoods. They don't carry more than 69 kV in most cases.
Burying Lines Reduces Downtime
Virginia's Dominion Energy has routinely resisted efforts by politicians and residents to force them to bury transmission lines. They say there are too many obstacles. However, Dominion Energy does bury its distribution lines. Not only that, but they say doing so reduces downtime significantly.
Dominion buried its first distribution lines in 2015. In the decade since, they say that they have reduced the "average outage times for those [impacted] customers from 11 hours to two minutes." Burying transmission lines has only cost customers an average of $4 per month.
The major benefit is not having to restore power to individual neighborhoods after damaging storms. Let's say dozens of neighborhoods go out as a result of transmission line damage. Repairing the line gets all those neighborhoods back online immediately. Previously, Dominion might have to send trucks into individual neighborhoods to repair damaged distribution lines.
Underground Transmission Is Time Consuming
One of the biggest hurdles of burying transmission lines is the time and effort it takes. In order to bury the lines, utilities need easements. Obtaining all the necessary easements from impacted landowners can take years. The time and expense add up very quickly.
By contrast, burying distribution lines requires much smaller easements of just 15 feet. A utility can go into a neighborhood, reach out to residence, and have all its easements wrapped up in a matter of weeks. The process is much faster and cost effective.
The thing is that all the easements must be obtained before construction can begin. So if weeks turn into months or years, the cost of obtaining easements is likely to go up. That makes an underground transmission project that much more expensive.
Underground Distribution Proves the Point
Time, costs, and easements aside, burying distribution lines proves that the concept works. Neighborhoods are less likely to experience damage to the lines that feed their houses. Maintenance needs are minimal as well. In theory, the same should apply to underground transmission.
It is true that transmission lines carry a lot more voltage. It's also possible that burying transmission lines could have more profound impacts on the environment than burying distribution lines. But again, the main point still holds – burying power lines (regardless of how much voltage they carry) reduces downtime by reducing storm related damage.
Find a Way to Make It Cost Effective
We already know that burying distribution lines works. It works so well that very few communities are built these days with overhead transmission lines. So proof of concept is there. Now the task should be finding a way to make underground transmission cost effective. Let us find a way to bury transmission lines more cheaply and quickly.
Underground transmission is emerging as a trend in some parts of the country. In other parts, utilities and regulators still bristle at it. But the chances are pretty high that underground transmission will someday be the norm. It's really a question of how quickly we get there and the ultimate price we pay to do so.
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