On a related note, power distribution in the South

To follow up on a discussion we held just after the Hurricanes, but which has slipped my memory as to when, there is a press release from Florida Power and Light, talking about the need to harden the power distribution system.  This is fairly relevant since the loss of power to refineries played a part in the length of time that they were off-line.

But apropos our discussion I thought I would just add a little quote:

Investing in Underground Conversions - FPL is committed to increasing its underground facilities. More than 37 percent of its current system is already underground. FPL will further its commitment by offering to invest 25 percent of the cost of converting overhead lines to underground for local government-sponsored conversions. By this action FPL is encouraging local governments to take the necessary steps to invest in conversion.

In addition, FPL will enhance existing efforts with local governments to strongly encourage ordinances requiring developers to provide underground electrical service for all new subdivisions, developments and projects. Furthermore, FPL will support legislation that would require similar action statewide. The company will also support efforts by municipalities to obtain federal or state funding to assist in underground conversions.

Undergrounding of distribution lines is much more expensive as a first cost than overhead lines.  However, underground lines have lower maintenace life cycle costs and are less prone to wind and weather damage.

The hurricances have shifted the economics towards undergrounding.

Here in California. undergrounding fees are built into the electric rates.  Each communitity then has an annual allocation of funds which they can build up for big projects.  They local government pays a big chunk of the total project costs but is aided by the fund.

For new development, many communities will zone it for underground utilities during the construction phase so that the costs are built into the price of the land.

I've heard a lot of complaining about overhead wires and transmission lines.  Sure, they are nicer but SOMEBODY has to pay 10X as much for that niceness.  

Does anyone know why the electric company started putting wires up above ground in the first place? It seems like it would be so much more expensive, given all the required maintainance, and cost of high power towers and wood and on and on. Burying them along pre-determined right of ways, seems like the logical choice. Just run it along side the existing Nat Gas, and Oil pipes that criss-cross the country???

Any thoughts

Robert NW ohio

I am not an engineer, but it would seem to me that the techonology for water tight, corrosion free conduit did not develop before the build out of the electrical grid before WWII. A WAG - As the the acronym list has it.
Electricity started in cities, like New York. They were running power to multistory buildings, so going above ground was the easiest.  No need to dig up the streets.

The overhead electrical lines were not expensive.  They didn't need to be protected like underground lines would have.  It was a rat's nest, with bare wires running everywhere.  There was at least one gruesome incident where someone who touched a wire was electrocuted.  His body hung above the streets, caught in the tangled wires for hours.  Rescuers were unable to get him down for fear of being electrocuted themselves.

Edison first started centralized generation and distribution of electricity from his Pearl Street Station in lower Manhattan, New York City.

He was definitely bootstrapping his operation with venture capital from J.P. Morgan (one of his first customers, on Wall Street.)

Overhead was cheaper and easier although he had underground too since his system was low voltage DC but it used a lot of copper.  Nikola Tesla dug ditches for Edison for a while.

One problem is that underground New York was owned by the Astors.  Putting stuff on the surface was one thing but burying wires required paying another set of landlords!

When Westinghouse came up with alternating current, its big technical advantage was high voltage which meant longer transmission and much less copper use.  Voltage far outran undergrounding technologies.  To this day underground transmission technology lags overhead.  For example, I know of no 1,000,000 volt underground line while such voltages overhead are commonplace.

It has long been a US policy preference for cheap energy and cheap electricity.  Overhead is so much cheaper than undergrounding.

Way back then work hours were cheap, copper was expensive, wooden poles were cheap, and porcelean were probably not that expensive and electrical power were a miracle, it did not have to look neat.

The first power cables I know about were insulated with oil filled paper made water tight with an extruded layer of lead and then protected with a wrapping of jute rope and steel bands. This is a robust technology that still is used for some cables. But it must have been expensive compared with the same ammount of copper or less in free air with some porcelean, steel and poles.

Did you realy electrifie after you built the pipelines??? Should it not have been the other way around?

The heating in the wires is fairly high - think of a resistor  many miles long, at say 400 KV (the UK transmission voltage I think). This is why it is inefficient to have power stations too far away from population or industrial centres where the power would be consumed.
Low and medium voltage underground conduit are a "solved" problem at reasonable cost.  High voltage is not.

I am aware of the cost to run 600 MW just over one km out (in a tunnel) from an underground hydroelectric power station and it cost over a million.  In another case, drilling under the Mississippi River for a HV line cost several million.

Putting most high voltage lines underground is just price prohibitive.  Induced current on the surface would cause problems as well.

Oil refinery power requirements typically require high voltage connections.

I never thought about the induction problems but you're certainly right!  We need to convert our HV systems to DC like the Scandinavians.  That would solve the induction problem though I'm not sure what method they use to step the voltage down.  500KV dc to 20 kV dc converters tend to be more expensive than transformers - though with current price of copper that may be changing.
There is no DC grid in scandinavia. There are multiple high voltage DC interconnects where grids need to be connected together across longer distances across water. And there are DC intreconnects (across water) with unsyncronized grids. And former Asea now the Swedish/Swiss ABB were a pioneer for this technology and still is one of the best companies for HVDC eqipment.

The step up and step down is made in transformers as AC.

There might be a small start of a kind of HVDC grid within in Sweden since a fairly long 400 kV AC line intended to add redundance to southern Sweden might get built as HVDC. I think this would be a good idea for technology demonstration but a bad idea for added redundacy per $ since a traditional 400 kV AC line easily and fairly cheaply can be connected to older lines crossing it between the endpoints giving extra redundancy. On the other hand it would be built with newer technology making it possible for it to convert active power to reactive power wich southern Sweden need more of.

The limit for AC thru cables is the parallell capacitance. Basically when the cable gets too long all the current fed into it charges and discharges this capacitance and no power is left to deliver in the other end.

If one would build a complete grid from scratch in the near future it might make sence to use +/- 10 kV DC or so to each and every house allowing cables with very little metal and losses and then step down the voltage. This will make more and more sence as power semiconductors are developed further. It has actually been sugested by some innovators in Sweden as an economical way to build a parallell redundant emergency power grid connected to centraliced accumulators and emergency diesels instead of every other company buing their own set that often is too small and badly maintained. On the other hand it would still be sensitive to lightening. And for the apocalypticons, EMP. ;)

Better/cheaper solution is do what Landsvirkun (Icelandic Power Company with aluminum smelters that CANNOT be without power fro more than a few hours (quarter billion to clean out aluminumsickles after they "freeze").

Their overhead HV wires are over 50% steel, rest aluminum.  Highest % in the world.  110 mph winds with 1 inch coated ice on wires.

Here in Oklahoma we have tornados. Well, duh, everyone says. Anyway, my friend timmy has been hit three times but even with the neighborhood in shambles he still has power. Other areas lose electrical power even in a light ice storm. They have above ground power lines from two different power companies OG&E and OEC. It doesn't take a rocket scientist to see that buried cables are better. Don't let anyone tell you that they can't bury the cables, because they can. In the long run it makes more sense. In the short run, it doesn't. Insist that new electric lines are buried, before it's too late.
I live on the Mississippi coast, and so (of course) I lost power during hurricane Katrina.  The power company gave me an option -- they would put in a new pole on my land and new line for free, or I could pay them to put it underground.  As I remember, they wanted about $2000 for this.  I went with the overhead.
Undergrounding isnt a slam dunk winner either.  While it certainly is more attractive from a visual standpoint and more secure from wind/storm damage it does not mean there are drawbacks.  

From a servicing standpoint, overhead lines are far easier to observe, inspect and repair than underground lines.  I discussed this and other pros and cons with a line engineer with SCE.  According to the engineer, his crews prefer servicing and troubleshooting overhead lines because the entire portion is visible.  If there are issues with an undergrounded circuit between transformers or other equipment, they pretty much have to replace the entire segment.  

Longer term, underground equipment and lines do have usable lifespans.  Which means there will come a point in the future where these lines WILL have to be replaced.  How long that lifespan is is dependent on the quality of the equipment and wires as well as how much load those circuits handle.  According to the engineer, early undergrounding equipment lifespans were approximately 30 years, give or take.  Most of what goes underground today will last 50 years or so, provided the electrical load remains at the rated capacity. 50 years is a pretty good length of time but as we know simply putting off a problem (the eventual need to replace the lines) into the future does not mean it will be addressed (or could be addressed) when that time comes. Repair and or replacement of undergrounded lines will almost certainly be more difficult to utility companies than the original undergrounding was (mostly performed by the developers).  

And that assumes that the raw material/specialized equipment is readily available and affordable.  

On a personal note, I lived in a subdivision (in Virginia) that was undergrounded in the early 60's with lines with a 30 year lifespan.  As expected by the late 80's the system was showing its age.  We would lose power every time it would rain more than one inch.  The utility could never locate the problematic section so after a year or so of undependable service they replaced the entire distribution section.

Makes you wonder which method is better in the long term.

    This issue has been discussed extensively in the DC area, where much of the system relies on overhead cables and power has been lost over large areas in recent storms. However, there are some underground cables and there have been problems in actually finding where these cables are - in some cases the records just aren't very good.
Technologies have been developed that solve some of these issues, with some of the same basic ideas (though obviously modified) as have been developed for replacing sewer lines, without requiring surface disruption.
Then you hook up a radio signal generator at one end of the cable and track it with a hand carried reciever and mark the cable run on the ground with spray paint.
This is good in theory, but it is sometimes lacking in practice.  A couple examples:

We were placing a traffic signal pole at an intersection for a 'hurry up' job.  The DOT rep brought the utility companies together on site and said, "We are drilling here (pointing to the ground) Monday with a 48" auger down to 22'.  Is anyone in the way? Yes or No."  An old worker from the local water company said there might be a problem because he didn't remember the water line being where it was marked (in the nearby ditch).  So they dug it up.  The 8" water line made a jog in the middle of the sidestreet but the locate guys didn't pick up on it because of the high water table.  Our pole foundation was actually closer to the locate markers, by 10', than the water line was.

Next: Fiber Optic contractors for the telephone companies are notorious for putting a couple big loops (10+') of fiber at the end of a run.  They just throw it out to the side and bury it.  The locates come along, and miss the big loop to the side and go to the junction box.  I know power would be in conduit, but 'stuff happens'.

The best underground utility locator in the world: a Backhoe.

We're pretty much all underground here for local distribution.  Yes it does cost more, but I don't mind as I can easily do without any "visual pollution" that is not absolutely necessary.  Reliability is a great advantage.

No undergound AC near pipelines please.  It not real great  inducing electrical currents in my pipelines.  Causes hell with corrosion protection.

One trouble with undergound electrical cables is the prarie dogs and other underground rodents that like to munch on the cable coatings.. at least until they bite through to the wire.  Another one is ... ants.  Ants like those warm underground areas around the cables where they connect to substations. They occasionally short them out with thousands of their little bodies.

Aside:  Thomas Edison was undoubtedly a great man, but he didn't "get it" right all the time either, my favorite quote by Thomas Edison, "There's no future in AC."