Capacitor to store lightning?

Discussion in 'General Science & Technology' started by cato, Sep 21, 2004.

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  1. cato

    cato less hate, more science

    Hi, this is my first real science thread on SF so go easy on me. :)
    I was thinking about how one might go about storing the power you get from a lightning bolt, and I came up with this idea.

    One could make the “dielectric”(insulator) material between the plates of the capacitor out of some gaseous or liquid substance. This would give the plates the ability to move (like an accordion), and thus, if you wanted to prevent arcing during the initial charge you could have the plates a bit farther apart. Moreover, because the plates can move you would be able to adjust the distance of the plates to get the maximus amount of capacitance without arcing. If you had a predictable amount of voltage you would not need this but I don’t think lightning is very predictable. :)

    So.
    1. Would this be a viable way to store lightning?
    2. What would make the best insulator/dielectric? Some liquid insulator, a noble gas, or just a vacuum? (I am leaning towards vacuum)
    3. If you have a better idea let me know, I welcome knowledge.
     
  2. dixonmassey

    dixonmassey Valued Senior Member

    If you cannot predict the charge deposited by lightning, how can you adjust your wonder capacitor? Once arcing in a capacitor began, it's too late to adjust anything. Usually, lightnings last for less than 1 sec. Why would you want to store lightning? Despite impressive voltages, power of a lightning isn't that great.
     
  3. dixonmassey

    dixonmassey Valued Senior Member

    Also, capacitors are very lousy vessels for energy storage (low energy density=huge sizes of capacitors to store practically significant amounts of energy). That's why cars, submarines.... have chemical batteries for the energy storage instead of capacitors.
     
  4. philocrazy

    philocrazy Banned

    are you serious?????????
    it would blow the hell out of your capacitor
     
  5. cato

    cato less hate, more science

    Ok.
    1. I said go easy on me =]
    2. You would start them out farther apart than you know you'll need needed, but after the lightning strikes, "less than 1 sec" you would have the plates adjusted via computer to get them as close as possible without arcing, thus improving the capacitance.
    3. I don’t really have a reason to store lightning; it is just a concept for discussion and thought.
    4. I know chemical batteries are better at storing energy, but how do you store a lightning bolt directly into a battery? The chemical reaction would not be a happy one. Moreover, if you could store it in a capacitor, you could use that to charge a battery. If you have an idea of how to store it directly into a battery then, by all mean, enlighten me. (That is the reason for this post)
    that is the reason I am discussing possible designs for capacitors that could stand up to that.

    p.s. I am not trying to prove my theory correct. I am merely interested in people’s thoughts on ways of storing that much juice.
     
  6. weed_eater_guy

    weed_eater_guy It ain't broke, don't fix it!

    your talking about storing all the electron discharge from a single bolt of lightening, which if you tapped it out slowly would make a good amount of power for a town for a month or so. Unfortunately, current capacitor technologies would require that your capacitor be roughly the size of Wyoming or something, several miles high. But that's with storing raw electrons, but if you somehow could instantaneously take that energy and convert it to a chemical energy in a battery, you might be able to fit that battery into a rather large facility, but there's no way we can make a battery charge instantaneously like that, so BLAM, the giant battery explodes or melts or something. Maybe have the bolt power some wierd process in a machine that craps out nuclear fuel or something... in a nice, compact, sweet little bundle of ludicrous amounts of energy... That'd be some REAL money there
     
  7. dixonmassey

    dixonmassey Valued Senior Member

    Well, size of your capacitor must be humongous = lots of inertia=even computer will not be able to beat 2nd Newton's law in less than 1 sec.

    Secondly, imagine lightning as a discharge between two gigantic atmospheric capacitor plates. Size of the lightning will be an estimate of a capacitor size (without dielectric) you'll need to store lightning energy. Dielectrics, multiple plates will decrease that size but still, it should be huge.

    If one wants to use capacitors to charge anything in controllable way, one must use resistors to adjust time constant (=RC). Humongous capacitor=humongous resistor=lion's share of power will be dissipated in a resistor.
     
  8. cato

    cato less hate, more science

    True. My theory was not really well thought out. Basically I was just trying to think of ways to capture the energy of a lightning bolt to start my thread out with more than just saying "how could one capture lightning". Perhaps oscillating it into the electrical grid, somehow, without blowing up everyone’s televisions that is =]

    Do you have an idea of what might work?
     
  9. Hideki Matsumoto

    Hideki Matsumoto ñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅB

    NOpe! a lightning bolt has WAY too much voltage to be completely stored. Waste of effort!
    Instead of storing lightning why don't you make some! Ask me. I can show you some easy ways to make lightning bolts!
     
  10. cato

    cato less hate, more science

    nah, thats ok. I was just trying to think of a way to store/use lightning bolts. what kind of a devise could use that super high voltage? A rail gun perhaps?(probably arc to much) perhaps redirect it to a enemies position in a war zone via a laser(*makes air quotes like doctor evil*)
     
  11. Nasor

    Nasor Valued Senior Member

    I'm not sure there's enough energy in lightning for it to be worthwhile.
     
  12. cato

    cato less hate, more science

    "A lightning discharge is incredibly powerful--up to 30 million volts at 100,000 amperes--but is of very short duration; hence lightning cannot be harnessed or used." (Zim Burnett)

    Not enought energy??? it has alot of energy, you just need to think of something that only requires a second or 2 of that very high energy. however, thats the purpse of this thread.

    "hence lightning cannot be harnessed or used"(this is what I am trying to solve, even if that is just redirecting of the lightning)
     
  13. weed_eater_guy

    weed_eater_guy It ain't broke, don't fix it!

    maybe in the future we could develop some kind of super-capacitor, using quantum physics or something to compres mass amounts of voltage instantly into small, building-sized power cells. Or maybe even phase the energy into another dimension or something crazy. the energy in a lightning bolt is all but ignorable, so i think as we become more and more advanced, man might start to seriously concider using this energy as we become more able to seriously harvest it. but as for right now, those bolts of pure energy are just part of a beautiful display on a stormy night...
     
  14. Pete

    Pete It's not rocket surgery

    It seems to me that lightning comes from a big capacitor to begin with (cloud-air-ground), so what you really want is a way to tap the energy in those huge natural capacitors before they arc out in a lightning strike.

    It's much more predictable that way, too... the biggest hassle in making an efficient lightning catcher would be getting it under enough lightning bolts a year to make it worth while.
     
  15. cato

    cato less hate, more science

    how good of a conductor would a laser produced ion beam make? Could you use that to slowly "tap" the power out of a cloud as it builds? it would have a lot of resistance, but maybe enough energy to keep ionizing the air, and thus keeping an area free of lightning(for whatever reason, fire hazard maybe)
     
  16. MRC_Hans

    MRC_Hans Skeptic

    As Pete says, the thing to do is trying to tap it before it discharges. Find a way to hoist a wire to about 10 miles, and you could tab some energy.

    The power of a lightning bolt is indeed enormous, but the energy is rather moderate, only a few kilowatt-hours. This is because the duration is so short, only a few micro-seconds. It seems to be longer, but that is due to two things: The flash persists on our retina for a considerable fraction of a second. Each lightning bolt is actually a series of very short discharges.

    As for your variable condenser (which would need a dielectricum that could withstand a voltage capable of arching many miles :eek: ), the idea of varying it could overcome the next problem you would have, if you actually managed to capture a lightning strike: How to use a charge of half a billion volts :eek: . By increasing the capacitance, since the charge energy in unchanged, you would lower the voltage, ideally to something more useful.

    Hans
     
  17. RadialEngineMan

    RadialEngineMan New Member

    Amazing how little is known about lightning, as demonstrated here in this thread.

    A careful reading of Ben Franklins famous experiment showed that lightning was electricity- and without a lightning bolt!

    He used the charging of the atmosphere to collect energy to charge his Leyden Jar- a crude battery/capacitor.

    No reason this method couldn't be done on a large scale.

    In a strike: Mention is made here in this thread of the need for a resistor: not so, a charging coil (reluctance) could be used to limit the surge of the high amount of electricity. Such a coil could also have the added advantage of acting like a transformer- transforming high voltage/low amperes to low voltage/high amperes. It has the advantage of eliminating the need for a variable capacitor.

    So sure, these things would have to be huge, but not the size of the "State of Montana"!

    The TV Discovery Channel had several programs showing lightning and it's effects. They used rockets trailing wires to channel the lightning to a target. This could be done as a form of control. A ionized path created by a laser might also work.

    To my mind, there are several possibilities of obtaining electricity other than the crude means we now use to make it. One is a way to tap the ionosphere- it contains a tremendous "Difference of Potential" as a result of solar cosmic activity.
    Could it be tapped with a ionized path?
     
  18. Nasor

    Nasor Valued Senior Member

    How many joules of capturable electrical energy are in the average lightening strike? I doubt it's enough to be worthwhile.
     
  19. Lava

    Lava Let discovery flow

    Part of a lightning strike can be stored by any EHT condensor. I remember reading a story about someone long ago who used a metal ball to store it, but made the mistake of going too near the ball one day: he was killed instantly by a bolt to the head form the thing.

    But to store the whole voltage of the strike you'd need a cap a mile high, as lighting is breakdown of air inuslation from sky to earth.

    What can you do with the power? I tried to work out how to harness and use strikes to heat a pool, by simply conducting them through the water; but the power captured was inadequate.

    The standard method to cause and capture a strike is to fire a small rocket with a copper wire tail.

    This sort of thing was played with a long time ago, look for a book covering leccy in the 1700s, in the days before electrical wire.


    Lava
     
  20. RadialEngineMan

    RadialEngineMan New Member

    Amazingly, there are 2 different types of lightning, (actually 3, if you count "Sprites" somewhat recently discovered). The type mentioned by Nasor is probably negatively charged and has a short duration measured in just a few Milliseconds, but the 2nd type which is positively charged has a burn duration measured in tens of Milliseconds and is extremely distractive.

    To capture such energy and put it to use, I would envision a massive inductor, which when struck with a bolt, would be able to transform the massive flow of energy and lower the charge with a secondary coil, or, using a movable core, like a solenoid, convert it to mechanical energy that could be stored.

    One way of using lightning is for experimentation, as we are not capable of creating such high voltages for examination of the distractive effects. Using lightning directly would be a real advantage.

    Concerning "Sprites": I believe these are created when the lower ionosphere "arcs over" to negatively charged lightning in high clouds. The ionosphere holds hundreds of thousands of volts caused by charging from the Suns cosmic particle bombardment. If we could just tap that........
     
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