sehari@iastate.edu (Sehari Babak) (06/05/91)
Recently, there were much talk about way to reduce the energy consumption. This not only saves money, but eventually saves life as well. Having this in mind, I am curious that haw much energy would we save. If we gold plate all Al wires that is used for transportation of the energy? Let us assume we have one mile of wire. It would probably costs around say $1000 to $2000 to gold plate this wire. Now depending on the current that passes through this wire, we might save $2000 to $4000 in the first year alone. This saving might increase even further, if the oil prices goes up again, which is a very likely possibility due to declining oil reserves of the world. Has any research been conducted in this way of saving energy.
jshapiro@mcs213a.cs.umr.edu (Jeff Shapiro) (06/05/91)
In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: >Recently, there were much talk about way to reduce the energy consumption. >This not only saves money, but eventually saves life as well. > >Having this in mind, I am curious that haw much energy would we save. If >we gold plate all Al wires that is used for transportation of the energy? [Stuff deleted] I don't have my CRC handy but I'm pretty sure that gold is only used for electrical contacts because it is pretty much inert. I think both copper and aluminum have better resistivities than gold. Anybody have any numbers? Jeff Shapiro jshapiro@cs.umr.edu
haynes@felix.ucsc.edu (99700000) (06/05/91)
One table I have shows the resistivity of gold is 1.4 greater than copper,
and aluminum is 1.6 greater. Silver is .94 relative to copper. The
reason gold is used on electrical contacts is that it doesn't form an
insulating tarnish film.
--
haynes@cats.ucsc.edu
haynes@ucsccats.bitnet
"Any clod can have the facts, but having opinions is an Art."
Charles McCabe, San Francisco Chronicleshirriff@sprite.berkeley.edu (Ken Shirriff) (06/05/91)
In article <16640@darkstar.ucsc.edu> haynes@felix.ucsc.edu (99700000) writes: >One table I have shows the resistivity of gold is 1.4 greater than copper, >and aluminum is 1.6 greater. I think this discussion of resistivity is missing the point; what matters is resistivity relative to cost. If material A costs 10 times as much as material B but has half the resistivity, you're probably better off making cables out of B that are twice as thick than using cables of A. (Assuming the material cost is the only significant cost.) In any case, I don't see what the sense of gold-plating the wires would be; that sounds like rec.audio voodoo. Ken Shirriff shirriff@sprite.Berkeley.EDU
wreck@fmsrl7.UUCP (Ron Carter) (06/05/91)
In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: >... I am curious that haw much energy would we save. If >we gold plate all Al wires that is used for transportation of the energy? > >Has any research been conducted in this way of saving energy. Conduct your own research. It's easy! 1.) Compute the amount of gold a dollar will buy. (It's about $350 for 1 Troy ounce, or 1/14 lb). 2.) Compute the amount of aluminum a dollar will buy. (Scrap is selling for around $1/lb; new might be $2.) 3.) Compute the diameter of a meter-long gold wire containing your $1 of gold. 4.) Compute the diameter of a meter-long aluminum wire containing your $1 of aluminum. 5.) Using values for impedance of metals (available in the CRC Handbook of Chemistry and Physics), compute the resistance of the two meter-long wires. The wire with the lower resistance would deliver power with smaller losses for the same cost, and is the energy-saving winner. So. What answer did you come up with?
digex@world.std.com (doug e humphrey) (06/05/91)
For your calculations, scrap aluminum, good bulk scrap and not a bunch of crushed cans that need a lot more processing, sells for 40 to 50 cents per pound; I am pretty sure that the finished product, in shape to make waire, or even already drawn as wire, will cost way under $2.00 per pound. Doug
henry@zoo.toronto.edu (Henry Spencer) (06/05/91)
In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: >Having this in mind, I am curious that haw much energy would we save. If >we gold plate all Al wires that is used for transportation of the energy? Uh, what makes you think gold plating will save energy? The only effect of a thin layer of gold plating on the surface, aside from making the cables pretty :-), will be to make them a bit more corrosion-resistant. Corrosion is not normally a serious problem anyway. To improve the conductivity of the cables, you're going to have to replace the bulk material, not just add a plated surface. P.S. Silver would be a better choice than gold for bulk conductivity. -- "We're thinking about upgrading from | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 to SunOS 3.5." | henry@zoo.toronto.edu utzoo!henry
dclaar@hpcuhe.cup.hp.com (Doug Claar) (06/05/91)
Gold plating wires might work, but there are already cable theft problems with the current materials. I don't see how you could keep people from stealing the cable. --Doug Claar dclaar@cup.hp.com
touch@gradient.cis.upenn.edu (Joseph D. Touch) (06/06/91)
In article <1991Jun5.163512.1314@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: >>Having this in mind, I am curious that haw much energy would we save. If >>we gold plate all Al wires that is used for transportation of the energy? > >Uh, what makes you think gold plating will save energy? > >To improve the conductivity of the cables, you're going to have to replace >the bulk material, not just add a plated surface. Are you sure? I thought AC travelled on the surface of the wire, not in the bulk, or is this just a very high frequency phenomenon? In that case, plating would help a bit - in fact, you could use the plating without the interior bulk (ala waveguides). Joe Touch University of Pennsylvania Dept of Computer and Information Science touch@cis.upenn.edu
tonya@hpldsla.sid.hp.com (Tony Arnerich) (06/06/91)
> Recently, there were much talk about way to reduce the energy consumption. > This not only saves money, but eventually saves life as well. > Having this in mind, I am curious that haw much energy would we save. If > we gold plate all Al wires that is used for transportation of the energy? > Let us assume we have one mile of wire. It would probably costs around say > $1000 to $2000 to gold plate this wire. Penny-wise and dollar foolish. How are you going to get the gold onto the wire?
simnet@ssc-vax.UUCP (Mark R Poulson) (06/06/91)
In article <43275@fmsrl7.UUCP>, wreck@fmsrl7.UUCP (Ron Carter) writes: > In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: > >... I am curious that haw much energy would we save. If > >we gold plate all Al wires that is used for transportation of the energy? Do you want to plate the wires or make them solid gold? Plating is only going to help where the cable is terminated. Solid gold conductors would be quite expensive. Note that power lines are rather large cable carrying tens (or is it hundreds?) of amperes and gold ones couldn't be a much smaller gauge. If you think that because the current is AC (so most of the current is carried on the outside of the cable) you should notice that 60Hz AC is not too effected by the skin effect so current flows throughout all of the cable. Resistance in terminations could be overcome by making much larger terminations out of cheap aluminum instead of small expensive gold ones. I think you would save more money by using larger diameter aluminum cable (or parallel cables of the size used now) to give a lower resistive loss. Mark
wb8foz@mthvax.cs.miami.edu (David Lesher) (06/06/91)
There's a story lurking about this topic. During WWII, some guys in a place named Oak Ridge needed some copper. It seems as if they wanted to play with electromagnets for some reason. ;-} Trouble was, LOTS of folks needed copper for other things, too. So the boffins got to thinking, and one with some special papers went one state away to a place called Ft. Knox - where he had an appointment with a big cheeze. After examining his guest's papers (that declared him to worthy of trust and confidence AND engaged in vital war-work) the cheeze asked: BC And what can we do for you, Dr. Boffin? DB We need to borrow some silver. BC Well, we don't usually loan out silver, but you appear to be very important. How much do you need? DB Oh, about 8 tons or so.... Guess the big cheeze got chest pains for some reason :_] But they got it all back! -- A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu & no one will talk to a host that's close............(305) 255-RTFM Unless the host (that isn't close)......................pob 570-335 is busy, hung or dead....................................33257-0335
ssave@ole.UUCP (Shailendra Save) (06/06/91)
From article <1991Jun5.163512.1314@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): > > Uh, what makes you think gold plating will save energy? The only effect > of a thin layer of gold plating on the surface, aside from making the cables > pretty :-), will be to make them a bit more corrosion-resistant. Corrosion > is not normally a serious problem anyway. There is something known as the skin effect, due to which, the higher the frequence, the closer to the skin the current travels. This is one of the reasons why the cables are never solid, but a bundle of thinner wires. The other reason is of course to have some tensile strength. With this knowledge, I would think that the bulk would not matter so much as the "skins" of the individual wires. So we would have to just coat the outermost wires with gold(so that they don't corrode) but coat all the inner wires with silver (since they are not in contact with external factors) so as to reduce resistivity to current through it. Just my 2.76 yen worth (today's rate). Someone please verify the skin effect stuff. Shailendra ssave@caen.engin.umich.edu sumax!ole.uucp!ssave
IO80900@MAINE.MAINE.EDU (06/06/91)
If I'm not mistaken, at room temps., silver is the best conductor, followed (somewhat closely) by copper, then gold, then aluminum. -C@G C.A. Gagnon IO80900@MAINE.BITNET io80900@maine.maine.edu But then again, what do I know...
rlbell@sunee.waterloo.edu (Richard Bell) (06/06/91)
In article <44194@netnews.upenn.edu> touch@gradient.cis.upenn.edu (Joseph D. Touch) writes: >Are you sure? I thought AC travelled on the surface of the wire, not >in the bulk, or is this just a very high frequency phenomenon? In >that case, plating would help a bit - in fact, you could use the >plating without the interior bulk (ala waveguides). > > Joe Touch > University of Pennsylvania > Dept of Computer and Information Science > touch@cis.upenn.edu AC does not use the entire area of the conductor, only the outer two-thirds. The inner third of the bundle is used for sturctural strength only, and is replaced with a steel cable. Because the overhead wire is made up of individual strands, it would be hard to plate the "outer surface".
luns@spocom.guild.org (Luns Tee) (06/06/91)
jshapiro@mcs213a.cs.umr.edu (Jeff Shapiro) writes: > I don't have my CRC handy but I'm pretty sure that gold is only used for > electrical contacts because it is pretty much inert. I think both copper > and aluminum have better resistivities than gold. Gold is third and Aluminum is fifth on the list. Specific resistances (resistance of a wire one foot long, one mil diameter, at 20 deg C) are Silver 9.9 Copper 10.4 Gold 14.7 Chromium 15.6 Aluminum 17.0 Titanium 19.2 Sodium 25.9 Magnesium 26.2 Calcium 27.6 Rhodium 28.2 Tungsten 30.1 Manganese 30.1 Molybdenum 31.9 Zinc 34.6 Iridium 36.7 Potassium 36.7 Nickel 41.7 Cadmium 42.3 Indium 50.3 do I need to go on? :-) Anyway, Aluminum is used instead of copper in power lines because its cheaper. Ontario Hydro says that they've had problems with people stealing copper power lines. =:-O As for Gold (and Chromium) plating, you're right on the money.
luns@spocom.guild.org (Luns Tee) (06/06/91)
shirriff@sprite.berkeley.edu (Ken Shirriff) writes: > I think this discussion of resistivity is missing the point; what matters > is resistivity relative to cost. If material A costs 10 times as > much as material B but has half the resistivity, you're probably > better off making cables out of B that are twice as thick than using cables > of A. (Assuming the material cost is the only significant cost.) > > In any case, I don't see what the sense of gold-plating the wires would > be; that sounds like rec.audio voodoo. There's one point you missed when it comes to RF connectors - the skin effect. At higher frequencies, electrons tend to travel at the surface of a conductor. If that happens to be oxidized copper or aluminum, the benefit of a bit of gold plating would be worth it. Along the length of a conductor though, the insulation is good enough to keep oxygen out.
elec140@csc.canterbury.ac.nz (06/06/91)
In article <1987@ole.UUCP>, ssave@ole.UUCP (Shailendra Save) writes: > There is something known as the skin effect, due to which, the > higher the frequence, the closer to the skin the current travels. > This is one of the reasons why the cables are never solid, but a > bundle of thinner wires. The other reason is of course to have some > tensile strength. > With this knowledge, I would think that the bulk would not matter > so much as the "skins" of the individual wires. So we would have to > just coat the outermost wires with gold(so that they don't corrode) > but coat all the inner wires with silver (since they are not in > contact with external factors) so as to reduce resistivity to > current through it. > > Just my 2.76 yen worth (today's rate). > > Someone please verify the skin effect stuff. What you say is correct as far as it goes. However the "skin depth" (ie the thickness of the "skin" carrying most of the current) is dependent on frequency. The higher the frequency the thiner the "skin" and you've got problems. However from memory, the skin depth at 50 Hz (yes I'm in that part of the world) is about 10 mm, which equates to a lot of gold !-) ********************************************************* Chris Kaiser Postgrad - Elec Eng Dept Canterbury University Christchurch, NEW ZEALAND E.MAIL: kaiser@elec.canterbury.ac.nz ********************************************************* "When you're fresh out of lawyers You don't know how good it's gonna feel" - Al Stewart, 1988 *********************************************************
johne@hp-vcd.HP.COM (John Eaton) (06/06/91)
<<<< < Let us assume we have one mile of wire. It would probably costs around say < $1000 to $2000 to gold plate this wire. ---------- One mile of one inch cable plated to 10 microinches of gold would consume about 2 cubic inches of the metal. With plating and handling your numbers look low. Perhaps we should try mercury filled power lines. John Eaton !hp-vcd!johne
myers@hpfcdj.HP.COM (Bob Myers) (06/07/91)
>Are you sure? I thought AC travelled on the surface of the wire, not >in the bulk, or is this just a very high frequency phenomenon? In You're referring to the "skin effect," which is dependent both on the frequency in question and the conductive material. In copper at 60 Hz, the skin effect is pretty much negligible. The formula for the skin depth - in millimeters - for copper is depth = 66.1/SQRT(f), with f being the frequency in Hz. For 60Hz, then, we have a skin depth of 8.53 mm, or about 1/3 in. Any practical plating of the wire, even if it were with a material of significantly better conductivity than aluminum (and gold *isn't*) simply wouldn't be worth the effort. Such "plated" wires (although I'm not sure that's how they're manufactured) are in use, however. For example, a type of wire called "copperweld," which has a copper cladding over a steel core, is widely used for antennas and other RF applications; the copper handles the RF energy, while the steel provides strength. A similar construction is used in some power-line cases, with a steel core surrounded by copper or aluminum strands, and for the same reason. A good question, though. Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not Ft. Collins, Colorado | those of my employer or any other myers@fc.hp.com | sentient life-form on this planet.
rwa@cs.athabascau.ca (Ross Alexander) (06/07/91)
touch@gradient.cis.upenn.edu (Joseph D. Touch) writes: >In article <1991Jun5.163512.1314@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >>To improve the conductivity of the cables, you're going to have to replace >>the bulk material, not just add a plated surface. >Are you sure? I thought AC travelled on the surface of the wire, not >in the bulk, or is this just a very high frequency phenomenon? Skin effect is a function of frequency. At DC, it's nil. It doesn't get particularly important until you're up around 100 MHz. Qualification of last statement: yes, I know all the lofer phreaks wind their stuff from Litz wire and they're only at 160 KHz or so. But I'm speaking of the really high-power domain, like kilowatts. At lower powers, does it really matter much that a % or two of the power is heating the cable? Not to me, for one. Also: a quick look in the Rubber Bible reveals that silver is significantly better than gold as a bulk conductor. Of course, silver is much more suspect to corrosion, but you can cure that with a coat of varnish. It's fairly common practise to silver-plate VHF and UHF cavities, but only the military bother to do this at HF. -- Ross Alexander rwa@cs.athabascau.ca (403) 675 6311 ve6pdq `You were s'posed to laugh!' -- Zippy
elec140@csc.canterbury.ac.nz (06/07/91)
In article <2470021@hp-vcd.HP.COM>, johne@hp-vcd.HP.COM (John Eaton) writes: > Perhaps we should try mercury filled power lines. > > > John Eaton > !hp-vcd!johne Now there's an idea! Substitute phone lines for power lines and sell it to AT&T for millions! You wouldn't need to send dc power down the phone lines then, you could pump the mercury down one line and back up the other, and use the flow to drive a turbine at the subscribers end! Of course you'd have to have a non-continuous flow at the sub's end, otherwise their phone line would be permanently shorted. A minor technical difficultly :-) ********************************************************* Chris Kaiser Postgrad - Elec Eng Dept Canterbury University Christchurch, NEW ZEALAND E.MAIL: kaiser@elec.canterbury.ac.nz ********************************************************* "When you're fresh out of lawyers You don't know how good it's gonna feel" - Al Stewart, 1988 *********************************************************
wlsmith@valve.heart.rri.uwo.ca (Wayne L. Smith) (06/07/91)
In article <7Fs532w164w@spocom.guild.org> luns@spocom.guild.org (Luns Tee) writes: > Anyway, Aluminum is used instead of copper in power lines because its >cheaper. Ontario Hydro says that they've had problems with people >stealing copper power lines. =:-O I've heard stories of people tying copper lines to the back of their pick-ups and driving down country roads, ripping the lines off the poles.
dave@seas.gwu.edu (Dave Owczarek) (06/07/91)
In article <7Fs532w164w@spocom.guild.org> luns@spocom.guild.org (Luns Tee) writes: > > Anyway, Aluminum is used instead of copper in power lines because its >cheaper. Ontario Hydro says that they've had problems with people >stealing copper power lines. =:-O > Today's Washington Post reports that an asteroid has been found orbiting the Sun at a distance of about 20 million miles from Earth (closest point). It apparently contains 10000 tons of gold and 100000 tons of platinum, as well as 10 billion tons of iron and 1 billion tons of nickel. Its estimated worth was put at around 1 trillion dollars. Lets haul it in and make gold power lines out of it. :^) -Dave -- ---------------------------------------------------------------------------- Dave Owczarek, Operations Team dave@seas.gwu.edu or uunet!seas.gwu.edu!dave The George Washington University Engineering Computing Facility, Wash. D.C. ----------------------------------------------------------------------------
gary@ke4zv.UUCP (Gary Coffman) (06/08/91)
In article <1987@ole.UUCP> ssave@ole.UUCP (Shailendra Save) writes: > > Someone please verify the skin effect stuff. Skin effect is of negligable effect at power line frequencies, bulk conductivity still rules. If you raise the frequency to take advantage of skin effect, you start to run into radiation losses as the length of the conductors becomes an appreciable fraction of a wavelength. For typical spans, most of the electrical energy would be lost to radiation across only one span at less than 2 Mhz. 300/Mhz defines the wavelength in meters for a given frequency. Long distance transmission today uses DC at ultra high voltage to minimize the amount of current the conductor is required to carry for a given amount of power. Power loss is proportional to I^2*R, so the lower the current, the lower the loss for a given conductor. Use of DC rather than AC eliminates radiation losses over the long spans of long distance power lines. Gary
sirakide@motcid.UUCP (Dean Sirakides) (06/08/91)
wlsmith@valve.heart.rri.uwo.ca (Wayne L. Smith) writes: >In article <7Fs532w164w@spocom.guild.org> luns@spocom.guild.org (Luns Tee) writes: >> Anyway, Aluminum is used instead of copper in power lines because its >>cheaper. Ontario Hydro says that they've had problems with people >>stealing copper power lines. =:-O >I've heard stories of people tying copper lines to the back of their pick-ups >and driving down country roads, ripping the lines off the poles. Of course there are the failed attempts: A couple a weeks ago in Chicago the charred remains of a man were found between two transformers on top of a ComEd pole. The man was wearing dish washing gloves and holding a hack saw (I think if I were going to steal copper I'd go after the plumbing :) Dean.
lrk@k5qwb.lonestar.org (Lyn R. Kennedy) (06/09/91)
wlsmith@valve.heart.rri.uwo.ca (Wayne L. Smith) writes: > In article <7Fs532w164w@spocom.guild.org> luns@spocom.guild.org (Luns Tee) wr > > Anyway, Aluminum is used instead of copper in power lines because its > >cheaper. Ontario Hydro says that they've had problems with people > >stealing copper power lines. =:-O > > I've heard stories of people tying copper lines to the back of their pick-ups > and driving down country roads, ripping the lines off the poles. We had one in Dallas where two guys climbed a power pole to steal the wire. The enterprise failed when they got to the 7200 volt stuf. One of my friends describes this as 'self policing'. Took a while to recover the bodies. ------------------------------------------------------------------------- lrk@k5qwb.lonestar.org 73, utacfd.utarl.edu!letni!kf5iw!k5qwb!lrk Lyn Kennedy K5QWB @ N5LDD.#NTX.TX.US.NA P.O. Box 5133, Ovilla, TX, USA 75154 -------------- "We have met the enemy and he is us." Pogo --------------
john@qip.UUCP (John Moore) (06/09/91)
In article <2943@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: ]In article <1987@ole.UUCP> ssave@ole.UUCP (Shailendra Save) writes: ]> ]> Someone please verify the skin effect stuff. ] ]Skin effect is of negligable effect at power line frequencies, bulk ]conductivity still rules. If you raise the frequency to take advantage At 60 Hz, the skin depth (where current density is reduced to 1/e of its value at the surface) is .85 centimeters. Thus, for large conductors it would have some effect. ]of skin effect, you start to run into radiation losses as the length of ]the conductors becomes an appreciable fraction of a wavelength. For ]typical spans, most of the electrical energy would be lost to radiation ]across only one span at less than 2 Mhz. 300/Mhz defines the wavelength ]in meters for a given frequency. Where the current flow is balanced in a power line (normal case), the radiation is negligible - the contributions by the conductors cancel each other out. -- John Moore HAM:NJ7E/CAP:T-Bird 381 {ames!ncar!noao!asuvax,mcdphx}!anasaz!john USnail: 7525 Clearwater Pkwy, Scottsdale,AZ 85253 anasaz!john@asuvax.eas.asu.edu Voice: (602) 951-9326 Wishful Thinking: Long palladium, Short Petroleum Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment! Disclaimer: The opinions expressed here are all my fault, and no one elses.
gibbons@csn.org (Hugh Gibbons) (06/11/91)
In article <sehari.676081817@du248-12.cc.iastate.edu> sehari@iastate.edu (Sehari Babak) writes: >Recently, there were much talk about way to reduce the energy consumption. >This not only saves money, but eventually saves life as well. > >Having this in mind, I am curious that haw much energy would we save. If >we gold plate all Al wires that is used for transportation of the energy? > >Let us assume we have one mile of wire. It would probably costs around say >$1000 to $2000 to gold plate this wire. Now depending on the current that >passes through this wire, we might save $2000 to $4000 in the first year >alone. This saving might increase even further, if the oil prices goes up >again, which is a very likely possibility due to declining oil reserves of >the world. > >Has any research been conducted in this way of saving energy. Electricity is transmitted at near-dc (quasi-static) frequencies; under these conditions, the skin depth (depth of penetration of the curent into the wire )is very long, so the wire would have to be essentially solid gold to really get a significant reduction in resistance. By the way, silver is a better conductor. -- -------------------- :-) Hugh Gibbons (-: --------------------