Why Don’t We Bury Power Lines Underground?

After a bad thunderstorm or power outage due to falling power lines, one question always seems to pop up: Why aren’t our power lines buried underground? Logic follows that if our power grid were underground, then tornados, windstorms, and many forms of harsh weather wouldn’t be able to cause huge power outages.

While there certainly is a case to be made for the benefits of underground power lines, the huge cost and the potential problems with undergrounding have kept the U.S. from fully embracing this type of power grid.

Why We Want Buried Power Lines

The advantages of undergrounding our power structure are obvious: lines would be less subject to damage from severe weather and other accidents both natural and man-made. There are also several smaller benefits, such as the raw amount of land that would be freed for other uses and a decreased risk of danger to wildlife caused by power lines.

Since it’s well known that the U.S. power grid could certainly use an upgrade, it’s only natural to ask why we shouldn’t just bite the bullet and invest fully in undergrounding.

Why We Don’t Have Them

The main reason why undergrounding hasn’t been fully adopted in the U.S. is the overwhelmingly high cost of installing underground power lines. Estimates place the cost of undergrounding power lines at roughly $750 per foot, compared with $70 per foot to install power lines the way we do today. At over ten times the cost, this would become expensive very quickly.

Take North Carolina, for example. In 2002, the state looked into undergrounding for their three major power companies after a particularly bad power outage that left 2 million people losing power. After it was priced out, North Carolina found that their project would cost $41 billion (six times the net value of those three companies’ distribution assets) and would require 25 years to complete!

“Buried power lines are protected from the wind ice, and tree damage that are common causes of outages, and so suffer fewer weather or vegetation-related outages,” their report concluded. “But buried lines are more vulnerable to flooding and can still fail due to equipment issues or lightning.”

Cost aside, there are several logistical problems that have kept undergrounding from emerging in the U.S. In addition to power lines, new transformers and switches would have to be built and buried to get power to our nation’s homes.

There is also the problem that being underground creates for power line maintenance. If there is a power outage in underground power lines, technicians will need to bring in earth-moving equipment to get to the lines and solve the problem. This is much more troublesome than climbing a pole—and a downright challenge in much of the country during the winter.

As if that weren’t enough, underground power lines are still vulnerable to the elements in some ways, notably flooding and earthquakes. This vulnerability was exposed during the 2011 Christchurch earthquake, when several hundred kilometers of underground power lines were damaged, compared to only a few kilometers of overhead lines.

Ultimately, the prohibitively high cost of undergrounding alone has kept the technique from widely spreading in the U.S. Unless big changes are made, undergrounding is just an impractical concept on a large scale.

Check out the rest of our Bright Insights blog to learn more about energy efficiency and the benefits of renewable energy!