Mar 21, 2025
Carrying electricity across miles of cables suspended high in the air has been the norm for decades.
Carrying electricity across miles and miles of cables suspended high in the air has been the norm for decades. Ever since U.S. cities became electrified, suspended cables have been a widely used option. But engineers are beginning to rethink things. As a result, underground transmission is a hot topic of conversation.
A conversation is certainly being had in California, where drought conditions can turn a typical brush fire into a raging inferno that destroys hundreds of buildings and injures untold numbers of people. Some of those fires, unfortunately, result in deaths as well. Could switching to underground transmission be the answer?
Sparks and Drought Conditions
The proposal to move California's transmission lines underground makes a lot of sense. We know that sparks and the dry brush drop conditions create do not play well together. One spark can start a fire without much effort. Throw in a little wind coming off the Pacific Ocean and that wind creates a dangerous disaster.
The recent Los Angeles wildfires could be related to power lines. Exact causes have not yet been determined, but some experts have proposed that at least one of the fires, the Eaton fire, was sparked by an unused power line. Edison International, the operator of the line in question, disputes any such assertions. But an investigation is underway.
Moving Forward With Plans
Moving power lines underground is now on the minds of city and state leaders across California. Out in Los Angeles, the LA Department of Water and Power recently announced plans to move forward with a proposal to bury some 4,000 lines underground.
The utility estimates spending between $1 million and $14 million per mile of transmission line. That is a lot of money. But is it, in comparison to the amount spent every year on recovering from wildfire damage?
As the thinking goes, investing in underground transmission now could ultimately save a ton of money in the future by preventing wildfires sparked by electricity transmission. It sounds reasonable. But will those costs be offset by other disasters that could affect buried power lines? Time will tell.
The Issue of Idle Lines
Underground transmission takes on greater urgency when one understands how idle power lines are addressed in California. State law allows utilities to leave unused transmission lines hanging from poles fully intact. As long as a utility routinely inspects and keeps the unused lines up to spec, they can be left in place indefinitely.
Some of these lines are still connected to the grid even though they don't deliver electricity to any particular destination. Others have been disconnected, but it has been theorized that they can be temporarily reenergized under certain conditions.
Adding to the difficulty is the fact that many of these unused lines travel directly through areas prone to dry brush and trees. By transitioning to underground transmission, two things would be accomplished: future power lines would be less likely to spark wildfire, and the plethora of idle lines would likely be dismantled. It would not make sense to bury the lines if they are no longer in use.
Underground Transmission Is the Way to Go
For a growing number of lawmakers and utility experts in California, underground transmission is the way to go. Burying transmission lines in the ground prevents sparks from starting fires on drought parched lands. But transitioning to underground transmission will not come cheaply.
After seeing the devastating effects of the Los Angeles wildfires earlier this year, it is hard to argue against underground transmission. Now we will see just how long it takes to get all of those lines underground.
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