1. Joined
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    13 Mar '09 19:512 edits
    http://www.claverton-energy.com/green-grid-article-in-new-scientist-by-david-strahan-the-oil-drum-on-hvdc-supergrids.html

    This explains how a continent-wide dc electric grid can allow us to generate all our electric energy from renewable energy ( this can be done within perhaps 30 years according to one conservative estimate mentioned in the original article I read although it doesn’t specifically say that in this shortened version of the original article) and without it costing too much. Whether the stupid politicians would actually make this happen or simply do nothing as usual is another matter entirely.
  2. Subscribersonhouse
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    13 Mar '09 20:112 edits
    Originally posted by Andrew Hamilton
    http://www.claverton-energy.com/green-grid-article-in-new-scientist-by-david-strahan-the-oil-drum-on-hvdc-supergrids.html

    This explains how a continent-wide dc electric grid can allow us to generate all our electric energy from renewable energy ( this can be done within perhaps 30 years according to one conservative estimate mentioned in the origi ...[text shortened]... icians would actually make this happen or simply do nothing as usual is another matter entirely.
    One thing I like about the idea of DC grids is less radio interference and it would be presumably more efficient for the simple reason: a 5000 Km 50 or 60 Hz transmission line starts to look more like an antenna.
    To transmit RF with a frequency of 1000 hz requires an antenna only about 150 Km long, if it is a dipole, it would radiate a high percentage of that energy. So 100Hz would only need a dipole of 1500 Km. So you need to do something to prevent that electricity from just radiating away. so 50 Hz would radiate if it were a dipole of 3000 Km, not an impossible length. So you would have to do some engineering to prevent it from radiating. One way is to use transmission line technique where you have two conductors spaced a certain distance apart, but not sure how effective that technique is considering you have to have wires charged up at several hundred thousand volts, and keep them far enough apart to prevent arcing and at the same time make an effective RF suppression system. DC would stop any such nonsense from the beginning, since there is no changing currents so no radiation, well at least during steady current drain times. I guess if there were jumps and falls in demand, some of that energy could escape as radiation but it would for sure be less than any 50 or 60 Hz line. The absolute best way, now way too expensive, is to do it with superconductors, that way you could have buried cable because the voltage would approach zero and the current would be huge so you could have a simple coax cable with proper cooling, whatever that would take, maybe none if they solve the riddle of room temperature superconductors. That would change the whole concept of power transmission, all those towers would disappear, AC AND DC.
  3. Germany
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    13 Mar '09 20:37
    No room temperature superconductors available (yet?) though...
  4. Subscribersonhouse
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    13 Mar '09 21:41
    Originally posted by KazetNagorra
    No room temperature superconductors available (yet?) though...
    It's the holy grail of physics.
  5. Germany
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    14 Mar '09 09:58
    Originally posted by sonhouse
    It's the holy grail of physics.
    Maybe. Even if one is found, it will probably be expensive to make, so copper wires will probably be around for a while.
  6. Subscribersonhouse
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    14 Mar '09 14:19
    Originally posted by KazetNagorra
    Maybe. Even if one is found, it will probably be expensive to make, so copper wires will probably be around for a while.
    Pretty good bet, that. What comes out of the labs and what comes out of commercial production are often two different things, also years after the lab results.
  7. Joined
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    15 Mar '09 21:532 edits
    Originally posted by sonhouse
    It's the holy grail of physics.
    shouldn’t that be “It's the holy grail of superconductor research”?
    I assume that the “holy grail of physics” is the unification of all the known laws of physics into one single law? (I could be wrong -“holy grail" is ill-defined)
  8. Subscribersonhouse
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    16 Mar '09 00:043 edits
    Originally posted by Andrew Hamilton
    shouldn’t that be “It's the holy grail of superconductor research”?
    I assume that the “holy grail of physics” is the unification of all the known laws of physics into one single law? (I could be wrong -“holy grail" is ill-defined)
    Well, maybe the holy grail of APPLIED physics then. Unification would be a bit more fundamental for sure. The thing is about unification, we have no idea what kind of new technologies that would lead to, probably something we can't even imagine right now, but room temp supercoductors? That would change everything in all aspects of electronics, heating and cooling, transportation, space travel (especially when we get to the point where we can make a working space elevator), computers, mobile devices, MRI's, levitating trains, energy transport, energy storage, radio communications(imagine superconducting antenna's, the Q would be in the millions so the same range of radio's of all kinds could be done with maybe 100 times less energy and reduced bandwidth, the antenna itself being a bandwidth pre-selector, imagine what that would do for radio astronomy), the list goes on and on what RTS's would do.
  9. Cape Town
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    16 Mar '09 09:04
    Originally posted by KazetNagorra
    Maybe. Even if one is found, it will probably be expensive to make, so copper wires will probably be around for a while.
    I believe carbon nanotubes have a conductivity up to 1000 times greater than copper. Now we just need to get the price down.
  10. Germany
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    16 Mar '09 09:15
    Originally posted by twhitehead
    I believe carbon nanotubes have a conductivity up to 1000 times greater than copper. Now we just need to get the price down.
    I think it's cheaper to make nitrogen cooled superconductor wiring than a grid of carbon nanotubes...
  11. Joined
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    16 Mar '09 19:09
    Originally posted by sonhouse
    Well, maybe the holy grail of APPLIED physics then. Unification would be a bit more fundamental for sure. The thing is about unification, we have no idea what kind of new technologies that would lead to, probably something we can't even imagine right now, but room temp supercoductors? That would change everything in all aspects of electronics, heating and c ...[text shortened]... agine what that would do for radio astronomy), the list goes on and on what RTS's would do.
    Point taken 🙂
  12. Subscribersonhouse
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    22 Mar '09 14:23
    Originally posted by twhitehead
    I believe carbon nanotubes have a conductivity up to 1000 times greater than copper. Now we just need to get the price down.
    Reference?
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    22 Mar '09 15:552 edits
    Originally posted by sonhouse
    Reference?
    I got just this one:

    http://en.wikipedia.org/wiki/Carbon_nanotube

    “…In theory, metallic nanotubes can carry an electrical current density of 4×109 A/cm2 which is more than 1,000 times greater than metals such as copper…”

    By accident, I found this while I was searching for the above:
    It is about a form of carbon called “lonsdaleite”

    http://en.wikipedia.org/wiki/Lonsdaleite

    “…the lower hardness of lonsdaleite is chiefly attributed to impurities and imperfections in the naturally occurring material, and a pure sample could be 58% harder than diamond.…”

    I assume that this is only “in theory”?

    Is it just me and the way my dyslexic brain sees things or is the molecular structure of lonsdaleite extremely visually confusing? :

    http://en.wikipedia.org/wiki/File:Lonsdaleite_structure.PNG

    Does anyone else find this visually confusing?
  14. Subscribersonhouse
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    23 Mar '09 00:29
    Originally posted by Andrew Hamilton
    I got just this one:

    http://en.wikipedia.org/wiki/Carbon_nanotube

    “…In theory, metallic nanotubes can carry an electrical current density of 4×109 A/cm2 which is more than 1,000 times greater than metals such as copper…”

    By accident, I found this while I was searching for the above:
    It is about a form of carbon called “lonsdaleite”

    http: ...[text shortened]... ipedia.org/wiki/File:Lonsdaleite_structure.PNG

    Does anyone else find this visually confusing?
    If you dig deeper into that link, there are '3d' simulations of the structure which looks like it makes more sense.
  15. Cape Town
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    23 Mar '09 06:22
    Originally posted by Andrew Hamilton
    “…the lower hardness of lonsdaleite is chiefly attributed to impurities and imperfections in the naturally occurring material, and a pure sample could be 58% harder than diamond.…”

    I assume that this is only “in theory”?
    I don't see why it should be only "in theory". There must be some way to create a pure sample and if so it should be as hard as predicted by the theory.
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