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Early on in the cartoon The Legend of Korra, we're shown one of the main characters working at his job. He works in a power plant, where he and his coworkers spend all day using Bending (essentially elemental magic) to conjure up lightning bolts and throw them at some sort of machine, to produce electric power for the city. But as interesting of a concept as it is, actual electrical systems depend on steady, predictable current; surges (such as the kind brought on by a lightning strike) tend to destroy electrical machinery.

Is there any way to make this system practical? Assuming the existence of a world with all the same physical laws as ours, but where elemental magic exists that allows for people to conjure up lightning at will, would it be possible to create such a power plant? And if so, how would it deal with the highly uneven current?

(Yes, this is tagged . Yes, the tag says no magic. The question isn't about the magical side of it, but the physical side.)

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  • $\begingroup$ How about an electric eel-man playing with a couple of diodes? $\endgroup$ – user6760 Aug 17 '15 at 6:23
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Not very realistic.

HowStuffWorks has an interesting article about generating electricity from lightning. There are several problems with harnessing natural lightning:

The logistical problems involved in making it work are significant. First of all, there's the basic fact that thunder storms are sporadic and lighting strikes random; considering that energy demands are steady, dependable energy sources are preferable.

Second, it's not so easy to capture energy delivered in one enormous blast in a split second. It has to be stored and converted to an alternating current, without blowing out the collection system in a single large strike.

Third, the energy contained in a lightning bolt disperses as it travels down to Earth, so a tower would only capture a small fraction of the bolt's potential. In the end, barring the development of a technology that could capture the energy from lightning before it strikes, it's probably best to focus on other, more earthly sources of energy.

The first point should be irrelevant here because the lightning can be activated at precise intervals. The third is unimportant because there should be no dispersal (I assume that this scenario takes place on short ranges). It's the second that is an issue. Capturing 5 billion joules in one second isn't easy. Perhaps if this is on a smaller scale, it could be plausible.

With better technology (i.e. capacitors for energy storage), this could happen, but it would take a lot of improvements. In the meantime, there's a chance that you could take advantage of atmospheric effects, such as this proposal using water vapor. I don't think that the manmade bolts would have the same sort of effect, though, because the environments are different. Perhaps you could try harnessing the thermoelectric effect, or use the lightning bolt to turn water into steam, turning a turbine.

Indirect energy capture is probably the best option here.

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    $\begingroup$ Actually, there is another problem, which this answer almost (but not quite) says doesn't even exist. Electricity demand isn't steady. Assuming the power generated is constant, if users need more current then voltage is going to drop. Real world power plants respond to this by increasing their power output as demand rises, and decreasing their output as demand lowers, thereby maintaining a stable voltage. IMO, any explanation for how the scheme described by the OP might be scientifically plausible would need to explain how the people involved respond to changing electricity demands. $\endgroup$ – a CVn Aug 16 '15 at 18:28
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    $\begingroup$ @MichaelKjörling Ah, I can add in something about that. I was more concerned with a drought of electricity in times of large power need, not the reverse (which wouldn't be as big a problem, though adjustments would have to be made). Given, though, that the intervals of lightning can be controlled (I think . . . ?) then the amount of strikes could be increased or decreased in response to this need, solving the problem. $\endgroup$ – HDE 226868 Aug 16 '15 at 18:31
  • $\begingroup$ Another problem is that while magic lightning bolts may be a free source of charge, without a place to discharge, there is no voltage. Every time charge is allowed to flow the ground (earth and electrical) will rise closer and closer to the same potential as the lightning bolt storage plate. $\endgroup$ – Samuel Aug 17 '15 at 22:53
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    $\begingroup$ So you're saying water benders would be a better power source? $\endgroup$ – T.E.D. Mar 23 '17 at 16:16
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So long as the electricity can be captured, yes, it could be feasible. The unevenness of the current could be addressed the way we do it in the real world. For example, using the energy from the bolts to power pumps that move water up to a reservoir. The water in that reservoir then powers conventional hydro-electric generators for steady and adjustable power generation. You can get upwards 80% efficiency with such a storage system. Though perhaps it would be even more efficient to use magic to move the water directly.

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