Winter is coming! That phrase was made more prominent during The Game of Thrones TV series. The coming winter also means the winter storm season is just around the corner, and the debate about overhead power lines versus buried power lines will rise again.
Many new neighborhoods had power lines buried and a few others have made the move to bury power lines – all at the cost of the developers or homeowners. The cost of putting power lines underground as opposed to overhead lines is exponential, both for installing buried lines and conducting service on those underground lines.
Even with buried power lines in your neighborhood, your power can still go out and that is due to how the power gets to those buried lines. Snohomish County PUD gets the bulk of it power from Bonneville Power Administration (BPA) sources like Eastern Washington hydroelectric projects as well as local sources. For Puget Sound Energy (PSE) serving Skagit and Island counties, most of their power comes from their own hydroelectric generation projects as well as wind farm power generation.
But that power takes a long journey to reach homes. First, the power is transported on high-volt transmission lines into the North Sound region. Then the power goes to substations and then distributed to primary and secondary lines to neighborhoods and businesses.
The high-volt transmission lines, and power distribution into and out of substations are nearly all above ground. As was seen in Louisiana as a result of Hurricane Ida, these above ground transmission systems can be damaged by nature’s fury. The same thing has happened in Pacific Northwest major storms such as the 1962 Columbus Day Storm and the Hanakkah Eve Wind Storm of December 2006. In that latter event, about 70 percent of PSE’s infrastructure was destroyed.
Cost statistics show the initial cost to bury power lines is three to five times more expensive. The usual cost of installing overhead power lines into neighborhoods ranges from $350,000 to a half million dollars per mile. For the same installation underground, the cost is up to $1.5 million per mile. That additional cost is passed onto rate payers, particularly for non-profit PUDs like Snohomish County PUD.
Then there is power restoration service. Maintenance and repairs on buried lines is far more difficult to diagnose and then service, often 3 to 4 times longer than overhead lines, adding to costs. Underground lines are indeed protected from fallen trees and limbs, but these lines have their own issues such as failures produced by overheating, water and corrosion, and by those who carelessly dig by not calling 811 and having such lines marked in advance.
In storms, a fallen wire can take as little as 30 to 60 minutes to repair while underground outages take at least a few hours just to diagnose what the problem is. Both Snohomish County PUD and PSE conduct tree limb clearing from overhead power lines along miles and miles of roadways each summer season, reducing the threat of fallen tree debris on lines.
Here is a recent example from our storm season’s first event on September 17th and 18th. Thanks to the wet and blustery weather, Snohomish County PUD had a number of outages. One response team was dedicated to a primary fault on an underground line. It took about 10 hours for the team to diagnose and repair the buried line that included part of it under a retaining wall. In the same amount of time, other line crews completed dozens of jobs repairing overhead lines, restoring power to thousands of customers.
The visibility of overhead lines is critical in finding damages to the power distribution system. Diagnosing problems with buried lines is far more difficult and time-consuming, resulting in greater repair times and costs.
For those who advocate for burying power lines, keep in mind the costs of installation and service in comparison to overhead power distribution systems. There are steps you can take to be better prepared in case of any power outage. September is National Preparedness Month and now is a good time to prepare in advance for the coming fall and winter storm season. Visit www.ready.gov or takewinterbystorm.org for helpful tips you can take now before the next storm hits.