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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?
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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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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In the Southeast United States fire ants are a big problem. The just love low- and medium-voltage electricity.
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There was an article in the Chicago Reader a couple of weeks ago about pets (and people) getting electrocuted from lines that were buried 40 or more years ago and were now corroding or fraying. It can actually cause wet concrete to basically act like a large shock plate. Not fun. It's also very hard to detect.
Here's a link to the article summary, though you'd have to pay $2 to actually read it.
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.
http://205.243.100.155/frames/longarc.htm#500_kV_S witch
Part of the thing *not* discussed here is that there are huge amounts of the power distro system in DC which *is* underground. The problem that they've run into - and I've had conversations with the people maintaining them - is that maintenance is a nightmare.
Getting to the underground lines is a bear and then making any changes is even worse. In most scenarios, they actually wait for the equipment to fail (eg. ignite and/or blow up) before they can do anything because the alternative is that they take down multiple city blocks for hours...
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Costco gets hassled for paying their employees more than the industry avg, giving them benefits packages above the industry avg and for not charging consumers more on the goods they sell.
Wal*Mart, is quite possibly going to run its suppliers out of existence because of the razor thin profit margins it allows them. Wal Mart also happens to save massive amounts of cash (which go directly to the bottom line) by not providing any meaningful benefits to their employees.
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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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DC Lines are really cool but damn it must costs a lot to procure the 500 MVA rectifier / inverter set up. I think having to buy an inverter is a major black eye for solar power as well (unless you have DC loads).
Long term it still costs more.
Even if you add up the costs over, say, twenty years and find you've spent more under the above ground scenario, it may still cost more if you include "opportunity costs". Suppose I could spent $25M to put in an above ground transmission system in an area, and pay out $25M over twenty years, vs. spending $50M for underground and for sake of argument 0 for maintenance of the same period. It's not a wash, because in the second scenario you have $25M in your pocket you can invest; in the first scenario you miss out on the interest.
There's an even simpler explanation as well. There is no market for power distribution. If you are dissatisfied by the reliability of your electrical grid, you cannot switch to a competitor's grid. The owners of the grid will charge you the cost of running the grid plus as much as they can get away with over that. They have no incentive to take their money and, effectively, bury it in the ground to give you another sigma of reliability. All they have to do is get you enough power so they can charge you, and not get nationalized by a furious public. Which might not be a bad thing, if you compare the interstate highway system to the electrical grid.
The most amazing thing about the electrical grid is that it works at all. And indeed most of the time it works well when compared to, say, Iraq. But although it works in routine cases, it does not work in even moderately exceptional cases, such as peak demand for air conditioning. And it certainly does not work to address problems like the California power crisis of several years ago.
Looking forward two to three decades, the electrical grid is probably the single most important piece of infrastucture to improve if the US is to remain a viable economic power. As oil production drops, and world demand rises, prices will rise. The grid is critical in enabling us to respond by bringing more diverse energy sources on line. The roblem is that many of these sources: wind, solar, tidal, geothermal etc. aren't located where the power must be consumed. And others, such as nuclear, are not politically practical to place neir population centers. And you can't build them overnight. Although we can see a trend of increasing oil prices into the future, when it comes it probably won't be smooth upward ratcheting off prices. It will probably come as a series of shocks (if it hasn't started already).
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