[mythtv-users] Underground vs. Overhead Utilities

Brian Wood beww at beww.org
Tue Jan 27 23:31:34 UTC 2009


On Tuesday 27 January 2009 15:53:17 R. G. Newbury wrote:
> Brad DerManouelian wrote:
> > On Jan 27, 2009, at 12:20 PM, Brian Wood wrote:
> >> Underground utilities cost a lot more to install and maintain than
> >> overhead
> >> ones. Ask the average person if they are willing to pay more for their
> >> house
> >> to have utilities underground and guess what they will say.
> >>
> >> They can be a bear to maintain, especialy in areas where it snows a
> >> lot. Try
> >> finding one of those little  pedestals in a bunch of snowdrifts.
> >>
> >> Of course in L.A., where it rarely snows, you have to use a torch
> >> (american
> >> meaning) to kill all of the black widows in the pedestal before you can
> >> safely work.
> >
> > Do you have numbers to back that up? I suspect it's expensive to replace
> > down wires and possible more insurance money for workers to climb poles
> > than to dig. I wonder if long-term there is actually cost-savings in
> > burying the wires where people can't easily get to them with cars,
> > kites, lightning, ladders, etc.
>
> I would make a small wager that doing a subdivision, etc. entirely
> underground ends up cheaper and is cheaper to maintain, then having
> electrical etc, on poles.
>
> Water and sewage have to be underground to start, so you have to dig. It
> is not that much more expensive to add pipe for natural gas, electrical,
> cable and telephone. Then you only have watch out for hungry backhoes...
> and worry about broken water-mains.

I have never heard of any place where water, gas and electric were in the same 
tranch. Can you imagine what would happen if a backhoe did hit that 
collection of utilities? i wouldn't want to be anywhere near it.

As was pointed out, the cable itself is more expensive for underground use. In 
most locations high voltage (at least primary, if not secondary) has to be 
isolated from low-voltage stuff like telephone and cable TV by a buffer of 
sand or other method.

A brief check of the internet will show that you would lose your small wager:


http://209.85.173.132/search?q=cache:h2K3uhArWM8J:www.sceg.com/NR/rdonlyres/465E6534-2FFB-4069-BF84-81465AEEF887/0/Undergroundvs.pdf+utility+cost+underground+vs.
+overhead&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a
(watch the wrapping if you want to go to this link)

The cost to place new transmission lines underground is about 8 to 10 times 
the cost to build
overhead lines. The cost to build underground distribution lines is typically 
four to six times
the cost of underground distribution lines

I also found this:
http://www.talgov.com/you/electric/tline_construct.cfm


In many cases there is an expectation that the economic benefits associated 
with underground electric installations are significant enough to offset the 
additional cost of those facilities. Unfortunately, the economic benefits 
associated with underground electric facilities are, in most cases, minimal 
compared to the difference in the cost of installation. 

Then there was this:
http://www.atc-projects.com/TL16.shtml

-- Why doesn't ATC place electric transmission lines underground?
Underground lines are considerably more costly and environmentally invasive 
than overhead lines. For this reason, the state Public Service Commission 
rarely supports or approves underground construction of transmission lines. 
It is ATC's responsibility to consider many factors, including cost and 
environmental impacts, when proposing new electric transmission lines. The 
most affordable industry standard is overhead power lines.

Also, very high primary transmission lines (say, over 300KV) can't be placed 
underground at all under any circumstances:

For higher voltage transmission lines (i.e., 345-kilovolt), undergrounding is 
not an option because at that voltage the lines cannot dissipate heat and 
become capacity bottlenecks on the system, defeating the purpose of building 
them. Less than 1 percent of ATC's 9,100-mile network of transmission lines 
is underground.

Finally, check out:
http://tdworld.com/mag/power_survey_unearths_trends/

Most people in the utility industry understand that underground utilities are 
not generally a "good thing", while most proponents of such service usually 
consider only the visual impact, not the cost and performance.


beww
beww at beww.org


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