[context: I’m in a small city of 6k people. This stupid town is known for constant power outages due to high wind and snow. Are they stubborn or is it really that hard to switch this small town to underground power so we stop having power outages anytime someone even sneezes?]
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It can be complicated. Practical Engineering has a (https://youtu.be/z-wQnWUhX5Y) on underground transmission lines.
Being underground does not mean immune from outages.
In addition to what others have said. I’d like to add. Underground infrastructure can be really fragile if coordination between utilities is horrendous. The road folks will dig up a water pipe, next thing you know it’s next to a gas main so there’s no gas. Then the electricity upgrade busts more stuff.
FYI, in Sweden all the local distribution power lines are underground. Only for transporting power for nation/region distances, the lines are overhead lines.
Cost, space, current utility pole utilization by other services and the impact on squirrels main mode of safe travel. Mainly cost, the cost to the 6k taxpayers, the city and the funding used for general city management.
In a town of 6k people with such a small tax base, is the cost worth the effort? The increase cost in consumer electric bills, bond measures required, new taxes and allocation of general city funds to this effort would negatively impact every other aspect of city government for decades. It would be cheaper to provide everyone with electric generators and fuel every season. The taxpayers who don’t have power outages would surely balk this expense.
But lets say your rally the town and start digging, because the snows coming and that breeze is feeling a little more utility pole snapping in strength…
– Moving electrical underground requires placement of concrete encased duct banks, manholes and vaults with installed transformer and switching equipment. Then there are secondary conduits branching from there to one side of the street and the other. Probably a lot more that we take for granted that would need to be put down there as well.
– This has to be placed citywide, impacting the residential areas adversely, may require the relocation of above ground structures or infrastructure and lawsuits from residents and companies having to adjust to make the project work.
– There are many services running underground already that would be impacted.
– Utility poles often serve multiple functions including hardware telephone services, cable television lines and fiber. Moving electric underground may not seem feasible if the utility poles and their issues in adverse weather remain.
– The City of New York (where I found some of these highlights) [did a study in 2013](https://www.nyc.gov/html/planyc2030/downloads/pdf/power_lines_study_2013.pdf) that looked at placing the remainder of their electrical underground. With 82% already underground, the estimated cost to get the last 18% was $7.8-$8.29 million per mile, or $42 billion.
– Most likely you will need to retain attorneys to fight all the lawsuits from things like eminent domain protests to activists filing a stay because power lines are utilized by a migratory bird species and/or extra cost to build a squirrel tunnels to replace their main mode of safe transportation for over a hundred years. Or maybe I don’t want an electrical substation near my house. Someone will have an issue resulting in litigation.
There’s a difference between relatively low voltage local distribution lines, and the extremely high voltage long-distance distribution lines.
Burying the low voltage local distribution lines (like a few thousand volts) is straightforward and only moderately expensive. You can take some regular cables with normal plastic insulation and just stick ’em in a dumb trench and pile dirt over ’em and it’ll be fine. It’s still a little pricey to do a whole town at once, but it can be done if enough people really want to.
Burying high voltage long distance transmission lines is a whole different thing – we’re talking about hundreds of thousands of volts here. That’s a massive amount of voltage that will arc through almost anything. These are virtually impossible to bury.
We have underground cabling in my town of 7000 and practically never get power cuts. That being said there were a series of strange power outages here recently and to replace a busted underground cable takes a lot longer (leaving you with no power longer) than overhead lines and also requires them to dig big holes across people’s gardens.
If the underground cables are why we very rarely lose power then I think it’s worth it but there you go. Also probably more expensive.
Transmission lines get under heavy load too. It would be difficult to abate the heat underground.
You can. In many places in Finland a lot of money has been used to Horizontal Directional Drill new (and better quality/higher voltage cables) to everywhere. Issue is that it is slow and expensive. And generally done along the roads so that adds extra costs.
There is no technical limitation for this. It is done all the time in urban areas and even really high voltage long distance transmission cables and undersea cables are done this way. Even water and sewage pipes are done like this.
Now… Does you town of 6000 people want to pay to do this? To drill cables to what ever is the next closest major connection?
Because it does save money when you don’t need to cut trees and clear the areas near the cables, also they don’t get storm damage. But it is a huge cost to do it – which is why it is generally done for new cables and areas.
To me it’s much like the stereotype of water pipes in England: they’re much easier to fix if they’re run on the outside and freeze.
You’d not have as many outages with last mile cabling underground. At the same time randoms digging and cutting the cables will become a problem. On the other hand trucks that are too high or cars crashing into the poles along with the weather outages are still an issue with above ground cabling.
I don’t live in the States but quite a few places have those tiny flags put out to mark cabling and other stuff. So digging might not be an issue if properly marked? In Sweden we put a brightly colored netting just under the grass so if someone digs the net will be pulled up and warn the operator before getting close to the actual cabling/pipes/etc.
Edit: if doing underground, absolutely add a huge amount of free conduit. If possible, add fiber at the same time, or later using the free conduit. If the city owns the conduit they can either sell parts to different providers, or better yet, rent the conduit to providers. Passive income to the city to use for whatever.
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