Can We Harvest Lightning for Energy?

[miggidy]

What about instead of building a structure to dissipate static electricity, to instead run a weather balloon (or blimp) with a long line attached to the ground. Could that perhaps serve as a cheaper alternative to capturing the static in the clouds?

From an electrical engineering perspective, the hardest part about capturing the energy in a lightning strike is indeed its very swiftness. You're probably aware that batteries must be charged very slowly; all batteries have some unavoidable series resistance, and trying to pump tens of thousands of amperes of current through even a tiny resistance will still generate an enormous amount of heat -- enough to essentially fry the battery.

If you really wanted to capture the energy in lightning, you wouldn't want wait until a bolt occurs -- that's just too much current in too short a period of time. Instead, you could conceivably build a tall vertical structure which is capable of continually neutralizing static charge between cloud and ground. This structure could move the same amount of charge as in a lightning bolt, but spread over a much longer period of time. A current of tens of hundreds of amperes is quite easy to deal with, and could be used to charge ultracapacitors, spin up flywheels, etc.

Building such a tower would be an engineering feat, however, and it's not clear to me (I'd need to do some calculations) that the economic value of the energy that could reasonably be captured this way would justify the cost of the structures.

- Warren

 

[taylaron]

im concerned that the amount of surface area a single wire exposed to the air is not nearly enough to capture a reasonable amount of electricity. to my understanding, you need a significant amount of surface area. by then, you've made a serious kite.
-that doesn't keep lightning from striking your blimpthough; unless you like fried blimp on a string 5,000ft above your head.
*good thought.

perhaps the same idea with a wire going to space (able to support its own weight) with a weight on the far end; so you would have a wire being supported by centrifugal force going through the atmosphere.
-then attach heavy-duty streamers miles long in the cloudy region to increase surface area to gather static charge. -still a kite though...

 

[lareth]

This is from a person with no experience at all, buyt I was thinking about this, and I could't sleep thinking about it. here's what my tired brain came up with;

If it was absolutely necessary to harvest lightning, or the electricity currents creating lighting, without thinking of the profit from it at first, how would it be if you divided the source of energy until the amps went down so much it could give out a little bit of charge to a single small capacitor or battery.

Lets say one has a huge metal rod, wide and thick, of some material which wouldn't fry easily. Then divide that by 2, and so on and so on until we'd have a thousand, or 100 000 (I don't know, I'm just making up numbers here) small batteries, with fast filling cababilities.

How would that work? Would it make any difference?

Or having a rod like that to harness the energy in multiple ways until the current would fall below enough to use in what we have now, and could be used instantaniously to light up towns or what not?

It would need something to ease the spikes of current in healthy ways, which do probably exist, but I no nothing about that. Think of all the bulbs popping when a lightning would hit the harvester..

 

[3.14pi]

This is a very good idea although will it be worth the money?

 

[Mech_Engineer]

1.21 jigawatts?!

[PLAIN]http://pneumaticaddict.files.wordpress.com/2008/12/doc_brown-full-1.jpg

 

[taylaron]

This is from a person with no experience at all, buyt I was thinking about this, and I could't sleep thinking about it. here's what my tired brain came up with;

If it was absolutely necessary to harvest lightning, or the electricity currents creating lighting, without thinking of the profit from it at first, how would it be if you divided the source of energy until the amps went down so much it could give out a little bit of charge to a single small capacitor or battery.

Lets say one has a huge metal rod, wide and thick, of some material which wouldn't fry easily. Then divide that by 2, and so on and so on until we'd have a thousand, or 100 000 (I don't know, I'm just making up numbers here) small batteries, with fast filling cababilities.

How would that work? Would it make any difference?

Or having a rod like that to harness the energy in multiple ways until the current would fall below enough to use in what we have now, and could be used instantaniously to light up towns or what not?

It would need something to ease the spikes of current in healthy ways, which do probably exist, but I no nothing about that. Think of all the bulbs popping when a lightning would hit the harvester..

Your Idea is certainly an option, although there are several impracticalities facing development. First of all, an average lightning strike is about 10,000 - 20,000 amps and lasts perhaps 20 milliseconds according to Mark Stenhoff.

Although tying a lightning rod into a parallel circuit with say, 100,000 500mAh capacitors on each end lead is a bit impractical the greatest barrier is the avalible charging time. The capacitors used would need to be able to charge in ~20 milliseconds and hold half a coulomb of electricity.

Well! I guess you need to stick one of these suckers somewhere there is a LOT of lightning! The lightning rod would need to be immense to get the frequency of strikes needed for a reasonable profit. Investors would want to see a near immediate profit from their money, not perhaps 5-10 charging cycles a year... Compare that to the cost of electricity and simply charging them at home. But of course, if you want to be green and use this method, the capacitors need to be used/ discharged very quickly or the charge will dissipate. Time time time!

-Tay