Forgive me if this has been asked…I did a search and found nothing…
As I sit here in my lovely Michigan Avenue office, perusing the sky line, I notice that there are no power lines right down town. Boss, friend, husband say that’s because they’re buried, underground, otherwise the city would just be a tangle of wires and cables.
So my question is…why don’t they just bury power lines and cables EVERYWHERE? Wouldn’t that prevent winter storm or thunderstorm power outages, not to mention make our country’s landscape a hell of a lot prettier?
it seems to me that as I write this, it’s a stupid question, and there must be one simple answer…but I can’t come up with it.
My observation is that in the newer suburbs, they are actually burying a lot of cables and power lines. However, sometimes they can’t go back and bury things later because that would mean carefully working around the gas and sewer and water lines, which is very labor-intensive and thus expensive. They save that for where it’s really needed, like in the Loop.
I’ll bet the main reason is the cost of digging hundreds/thousands of miles of tunnels is magnitudes greater than the cost of stringing wires across cheap and ugly metal pylons.
Also wouldn’t maintenance be a lot easier if the cables are above ground?
Still, this is small justification for environmental vandalism.
[ul]
[li]Cost - It’s cheaper to keep power cables above ground “out in the country”. It costs more to dig. Also, you’d have to sheath them to protect them from groundwater.[/li][li]Safety - You don’t want some bumpkin to dig one up.[/li][li]Practicality - Where I grew up in Colorado, I often saw power lines running directly over mountains and ridges. It’d be really tough to bury them in rock.[/li][/ul]
In cities, however, since so many conduits are already dug, it’s less of a problem to include power lines. Also, they want to keep the skyline clear so that everything from semi-trailers to construction cranes won’t get tangled in power cables.
It’s more expensive to install, but the long term cost depends on the area. In areas with bad weather, it makes sense to bury lines as much as possible, to prevent icing, tree limbs falling on them, etc. In areas with milder weather, it’s not as big a savings. I’d bet it depends somewhat on the philosophy and accounting of the utility- invest in more up-front infrastructure costs, or have a larger ongoing maintenance budget.
I think housing developers may actually be able to pay extra in some situations for underground lines if a new development is going in.
It’s hard to go back later and bury wires. In residential areas, you may have to get new right-of-ways (very difficult ), not to mention the enormous damage you’d have to do to stuff in the way (like driveways, etc.). It’d be even MORE expensive if you tried to go around all the obstacles. This just gets worse in a city …
On top of all that, with power companies trying to be more competitive today, it doesn’t make sense for them to spend large amounts of money rewiring neighborhoods that already have power.
In the UK most of our stuff is underground, at least in urban areas.The major exception being telephone lines from the final junction box to the users property.
The Electrical grid though is mostly on pylons but there is a healthy lobby that has succesfully forced the companies to put them underground, especially in areas of outstanding natural beauty.
Putting 400KV cables underground is very expensive.It is usually a major construction project.
To achieve the necessary insulalation the cables have a hollow core(this is designed to bleed into the main insulating material) which is filled with oil.This oil does not move but does ahve to be kept at pressure which introduces a whole new layer of complexity.
The cable has to be kept pressurised by intermediate jointing stations along its length.Whenever you are dealing with high current devices at these sorts of voltages everything tends to be physically large, this being partly due to the need for separation distances between differant parts.
The equipment needs to be held in secure, well fenced compounds(which are large and costly).You would not believe the number of Darwin award candidates who try to gain access to fool around inside.
It also makes the land above useless for many applications since it always has to be available for digging up, and again adds significantly to the cost.In the most recent ones I have seen being installed, the land above the cable is used for things like firebreaks in forests, or grazing land for livestock.
Set against all that though is that underground grid cable networks are more reliable, and once the capitl costs are out of the way they are cheaper to run.
I seem to recall the figure “a million dollars per mile” being thrown around when my town buried power lines along a four-block stretch of the old downtown area as part of a beautification project. The odd thing is that they only did it to one side of the road, so what’s the point?
I think most of the time I don’t even notice how many power lines (and other types of cable) are strung up all over the place in suburbia. Sometimes, though, I’ll be sitting in my car at an intersection and suddenly realize what a huge difference it would make to have them underground.
I once saw an old (ca. 1900) picture of a neighborhood in a big American city showing telephone poles with about a dozen crossbars, each bristling with wires. This was in the day when a cable could only carry one conversation at a time instead of the (hundreds of thousands?) that a modern fiber optic cable can carry. So I guess we’ve made some progress since then!
i understand how expensive it would be and I guess that’s the obvious answer that I couldn’t come up with. Would the wires also contaminate the ground somehow? I mean, people are afraid to live near power stations, i can’t imagine they’d want them running under their flower beds.
