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Why Aren't Powergrids Underground?
jonging asks: "It is common knowledge that an underground power grid is less susceptible to the effect of a large thunderstorm. The American Transmission Company cites numerous reasons why it (and other power companies I assume) do not bury their transmission lines underground (e.g. environmental concerns, cost of installation and repair, etc.). Exactly how detrimental are underground transmission lines to the environment? Wouldn't the time spent without a power outage generate more than enough revenue to offset initial costs? Aren't the need for repairs in cities with successful underground power grids rare?" The linked article goes into extensive detail about the disadvantages in initial costs of putting in underground lines, but doesn't go into any detail about the maintenance costs of either option. With storms getting worse and worse (Maryland, DC and Northern Virginia have weathered torrential downfalls this week), might underground lines prove more resistant to storm-related power outages?
Sure, it would be nice to put it underground, but it costs more that way...
This issue is a bit more complicated than you think.
Though I'm not addressing TFA directly, let me comment on the DC thing. Yes. We have been utterly hammerered unto oblivion with rain in the last 5 days. But even at that, the power grid in DC is remarkably stable.
My office, which is about 3 blocks from the White House, has never had a major event that would have an effect on our network. In about 10 months of running monitoring 24/7 on our UPS, I've never seen a major "power event" (outage, surge, something else big). I've never seen a big spike or dip. Hell, I've barely seen any variation at all in the signal.
Perhaps it's a function of living in the big city. Perhaps it really is the fact that I'm on the same power grid as the White House. Perhaps it's just a coincidence and some really nice wiring, and me with a little too much tinfoil in my hat. Regardless, I think something is special about the power grids in the DC area.
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More expensive to dig, harder to cross roads/othershit when digging, MUCH easier to repair above-ground lines than below-ground lines (all you need is a cherry-picker truck), and what would squirrels walk on if there weren't above-ground power lines?
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It's true that underground lines require less maintenance. A lot less maintenance. If we changed all our lines from overhead to underground, NES would have to layoff 4/5 of their maintenance team. Rather than realizing that it would take years to convert every powerline in Nashville from overhead to underground so they'd have excellent job security until they retired, they have decided not to convert to underground lines. I wouldn't be surprised if this is true in other areas, but I know that's the deal here. So everytime there's a thunderstorm the power goes out, and the cable goes out with it, cause the cable lines follow the powerlines.
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And you know what? I'd say it looked pretty damned nice.
You know what else? I sound like a old rambling grandpa. I remember in my day to get to Taliesin we had to walk 5 miles uphill both ways in the snow...
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Each cable that transports AC is subject to drain by the capacity the parallel lines themselves represent. The closer the wires, the higher the capacity. At about 30 km on a regular high voltage cable, you reach a point where the reactive power drain reaches the maximum power the cable can transport - the cable is saturated without draining a single watt at the end.
DC does not have this issue however then you have all the problems that killed Edison's original DC power distribution in favor of Telsa's AC distribution.
Peter.
My apartment complex has its power fed in through a buried line, and I can attest to one good reason why power companies may not want to bury all (or even most) of their power lines: water.
My power has gone out three times already, this year, due to water seeping in where it shouldn't and causing a major short. Aside from the obvious risk of losing power, there's also the possibility of pedestrians and pets being electrocuted.
~UP
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Underground powerlines would suffer higher capacitive losses than overhead lines, and losses between the generating plant and the user would be power that the utility company can't (directly) bill for.
With all the public concern about EMF exposure, the situation would be made much worse when all those distribution transformers move from 40' up a pole to concrete pads at ground level. And then there is the everpresent problem of "backhoe fade"...
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In the Southeast United States fire ants are a big problem. The just love low- and medium-voltage electricity.
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Downtown Washington rarely has power outages because the power lines are underground.
Here in Australia, or at least large (for big values of large) amounts of it, it's all above ground too. Where I'm coming from, the Netherlands, it's all below ground.
When I discuss it with the people here, they give me all kind of reasons why it should be above ground (limited but not only to unable to quickly repair, the famous cable cut from people digging and, believe it or not, the people who are doing the repairs now would be jobless).
Just a quick glance about how it could be done and you'll see that it would be quite a trick anyway: All footpaths in Australia are large blocks of concrete or asphalt, and the nice small tiles you see in shopping centers are also just laying above a concrete layer. Opening up that would be a major++ operation. Compare it to the Netherlands where all footpaths (and most of the bicyclepaths) are just 30x30 cm tiles laying on top of yellow or black sand, you'll see that it has a historical tradition to put things underground and have them easily accessible.
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We could continue to debate this endlessly, but maybe you could save time and just read the official report?
I'll also mention that 4 of the 5 NYC boroughs (Manhattan, Brooklyn, Queens, and the Bronx) have their electricity distribution almost entirely below ground. It was a massive investment, but it was long ago.
I work for an electrical contractor in Eastern Iowa and we regularly have to work near these high lines and work with the power companies. As far as I can see, it is exceedingly expensive to bury these wires. There are alot of farmers around here and they regularly hit buried power lines when digging in their fields. This is a often an expensive and timely problem to fix involving the power company, an electrician and usually a whole day. I noticed the article doesn't say maintenance issues. From my experience, they need less maintenance, but the particular maintenace is very costly in money and time.
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In urban areas in Sweden it's all below ground. It's in part, I believe, because of snow; rural areas (where underground cables become far too expensive) have a predictable power outage mess every winter as some storm weighs down lines enough to break them (cue predictable news images of army units clearing snow off calbe poles and some farmer with no backup generator milking his cows by hand). It's also because of zoning laws - power companies have no choice. I believe much of nothern Europe at least is similar in this regard?
Here in Japan, on the other hand, it's all above ground. In part because of the relative lack of zoning laws (Japanese city architecture is delightfully, ah, surprising as a result), but according to people here it's mosty because of the prevalence of earthquakes, the one thing buried cables are not protected against. Sure, overhead cables will break too, but it'll be easier to fix.
I can understand the situation here in Japan, but really, it's a pretty hideous sight. So your power may end up getting slightly more expensive as a result (though this is dwarfed by other factors), but it's worth it. If saving money is all there is about city living, why not allow people to dump their trash in the street as well?
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I've been building power plants and other industrial projects for 15 years now. We encase all cabling in ductbanks (conduit & rebar in concrete, usually dyed red) and only a determined idiot will knock these lines out of service.
To address the issue with power loss through induction, yet it happens and it's dangerous. We had a run of pipe being welded up directly under a 100+ kV line leaving a substation. After getting several hundred feet welded up, they started having spot fires in the area. After several calls to the local FD, the FD Chief was getting pissed so they were walking the area down, heard a zzzzzssshhhtt (best I can describe) and sure enough the lines were inducing a current into the pipe (creating a large cap) and once the charge was large enough it arced to the ground, sometimes in a area with dry leaves & pine needles.
Also on another project we had a 12kV line in a ductbank piggybacking a 100pr data cable which fed our T1/T3 lines and we kept blowing the phone companies coils on their end and causing havoc with our digital phone system. Finally one day I was re-wiring the phone system and got zapped. Voltmeter showed 60V, not sure of amerage but it smarted. Idiots who installed the 12kV line didn't bond the shield so we had a current inducted into the 100pr.
So, yes power can be run underground but you better encase it and know what you're doing or hire someone who does.
Reminds me of this thread
The Backhoe, The Internet's Natural Enemy
Always carry a length of fiber-optic cable in your pocket. Should you be shipwrecked and find yourself stranded on a desert island, bury the cable in the sand. A few hours later, a guy driving a backhoe will be along to dig it up. Ask him to rescue you.
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Out in the air the water drips off and broken cables are easier to get to.
Companies like this rarely ever build infrastructure unless they can get an enormous government grant for it they can milk mercilessly while providing something that doesn't work or barely works - so are unlikely to be involved anyway.As weird as it may sound, quite a number of small towns here, in Ukraine have their powergrids (mostly) underground. It is so because in the 90s it was not uncommon for every piece of cable/wiring to get stolen sortly after being installed. So, back in day it used to be financially effective. Now with crime rates down it, probably, would not be worth the price, thought. But it stays as it was.
"Long term it still costs more."
I'd say that's debatable. My power bills were more in Denver than an hour north. In Fort Collins, Colorado, a study found that the quality of life was higher because the skyline lacked the unsightly transmission lines. I can say, being here, that it is a benefit to creating an overall, less-clustered atmosphere (I like to see the mountains when the pollution isn't in the way). The plan to bury lines was started before the town started growing, so various infrastructure was already well established to handle a growing population, e.g., roads, schools, etc. The cost of labor, materials and fuel was also cheaper when they started the program over a decade ago. They continue to add more buried lines to new neighborhoods and are still burying exposed lines in the back of older neighborhoods to this day. I'd like to note that our city handles water and electric, not a privately-held utility, like our gas company, Xcel.
Sure, our town is in a budget crunch. Well, more like we have a six million dollar deficit, but there's other reasons for that. I've often wondered why places like Florida don't bury their lines as they suffer so many storm-related disruptions. That's got to take a bigger hit on the economy, but when you think that every person has to start over to some extent, they will spend their insurance money on a new PS2 as much as a new house (unless the insurance company goes broke trying to settle claims). The Miami Herald has an article about the debate to bury or not to bury:
http://www.miami.com/mld/miamiherald/12502044.htm
The long-term cost of maintaining the conduit may be offset by increased services the government can give in the event of crisis because they don't have to bear the cost of repair and/or the cost of lost productivity when responding with reduced public services. I admit that the environment here is completely different than Florida. I would imagine, because it is dry here, we don't have to worry too much about drainage/plant related problems with our conduits, but ICBW... I also notice that our utility crews seem very well-prepared and, at least, look like they're working!
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I presume that the Germans, because of the constraints of their language's syntax at the end of which their sentences most of their verbs must put, cultural constraints that ahead they must think required are.
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Why this is modded +5 informative shows how bad the average person's logic is. Unless you pegged my sarcasm meter (which is possible) it seems more plausible that keeping the nations government stably powered is a more significant factor than the placement of the lines.
Power has gone out at least once a year for the past five years to my (Downtown San Francisco) neighborhood. Due to underground power lines. A couple months ago an underground substation exploded and burned the hell out of a woman walking on the sidewalk. A couple years ago directly in front of my apartment a short underground ignited flammable (sewer) gases which blew the manhole covers 40 feet in the air (And the power out for the whole day). No one was hurt, but one of the covers did go most of the way through a car.
My UPS gets a good work out.
Why does this discussion suddenly demand an anti-european outburst? Is it wrong to point out Europe's good experience with underground powerlines?
You yanks can have as lousy an infrastructure as you please. The rest of the world doesn't care how poorly you arrange your society. In fact, the US neglect of it's infrastructure gives the rest of us a competitive advantage (and even more so in the future).
However, the original post talked about power outages from thunderstorms, which -- excuse me -- is a HUGE problem in the US. I have lived in your country for several years, and been on numerous visits, and my experience is that power outages happen frequently in the US, whereas in Europe, it is a rare event. I remember one ice-storm in New Haven that brought down all the city's powerlines and it took weeks to repair. What you have to ask (and the original poster does) is whether the electricity companies across the country are scooping the profits from consumers without making investments that will ensure/improve the supply for the future. The electricity company does not pay the economic losses of thousands of other companies due to power outages.
So why not leave your flag-waving patriotism behind for a few moments and relate to the actual problems?
Germany has 1/3 the people of the USA crammed into a space 1/27th the space.
That might suggest that a single US utility consumer might be paying for a bit more infrastructure.
It is not the full 9x factor that the numbers imply since you can localize your sources, but it is a SIGNIFICANTLY larger distance that must be covered to convey the same service.
This is true of highways.
I find it absolutely amazing that our prices are even in the same ball park as those of Europe on goods and services that are impacted by population density. In most cases in the US it is cheaper even if you do not take government subsidies into consideration.
Ok, train travel is MUCH cheaper in Europe, but electricity, water, septic, garbage, postal, trucking, auto and air are all cheaper in the US.
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