# Why can't we capture lighting?
**URL:** https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370
**Category:** Factual Questions
**Created:** [June 28, 2002, 1:02pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370 "2002-06-28T13:02:17Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@DrLiver](https://boards.straightdope.com/u/DrLiver)
#### Post date: [June 28, 2002, 1:02pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/1 "2002-06-28T13:02:17Z")
Is it true that a lightinging has enough electricity to power an entire city for a certain amount of time, if so why is it so difficult to “capture” it and use it.
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### Author:  [@Aro](https://boards.straightdope.com/u/Aro)
#### Post date: [June 28, 2002, 1:06pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/2 "2002-06-28T13:06:40Z")
No one knows where its gonna strike next.
It’s ’ lightning ’ BTW
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### Author:  [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)
#### Post date: [June 28, 2002, 1:12pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/3 "2002-06-28T13:12:16Z")
Aside from that, once you capture it, it’s not lightning any more… It’s a stored potential!
::Geeky rim shot::
_Thank yew… I’ll be here all week!_
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### Author:  [@astro](https://boards.straightdope.com/u/astro)
#### Post date: [June 28, 2002, 1:16pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/4 "2002-06-28T13:16:56Z")
> [@](#):
>
> \*Originally posted by DrLiver \*
> \*\*Is it true that a lightinging has enough electricity to power an entire city for a certain amount of time, if so why is it so difficult to “capture” it and use it. \*\*
Being able to convince lightning to strike a certain point enough times to be useful might be problematic and although lightning has a tremendous amount of power it’s of extremely short duration so the amount of useful power might not be as much as you think. Lastly, building a device capable of absorbing lightning strikes and then storing and releasing them as useful grid power might be a lot more expensive than the relatively limited amount of power capturing lightning strikes (if even feasible) would justify.
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [June 28, 2002, 1:31pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/5 "2002-06-28T13:31:10Z")
> [@](#):
>
> \*Originally posted by Aro \*
> \*\*No one knows where its gonna strike next. \*\*
That’s not really a problem. Look at this photo of [lightning striking the Empire State building](http://www.crh.noaa.gov/mkx/slide-show/tstm/slide53.html). I’ve personally seen lightning strike the John Hancock in Chicago and I’ve seen a timelapse (or composite photo…not sure which) of lightning striking the John Hancock a dozen times in one storm…the building was ringed with lightning bolts. Of course, this is fine for the building as they are made to be lightning rods to ensure the lightning doesn’t strike something we wouldn’t want it to.
Unfortunately capturing that much energy is difficult. Basically you want a capacitor hooked up to your lightning rod to collect energy. A capacitor large enough to store the lightning’s total energy would be HUGE and probably impractical. Even the biggest capacitors made today wouldn’t store enough energy to make it worth the effort to hook them up to a lightning rod to collect whatever energy they can handle. Even if I can guarantee charging the capacitor during every lightning storm lightning storms are infrequent and unpredictable. In the end it is just cheaper to generate the electricity.
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### Author:  [@DrLiver](https://boards.straightdope.com/u/DrLiver)
#### Post date: [June 28, 2002, 1:32pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/6 "2002-06-28T13:32:24Z")
I remember a TV show I saw about the highest buildings and towers in the world; a scientists was saying that some of the highest towers get hit by lightning several thousand times per year; wouldn’t that be enough to justify building a lightning ‘captor’.
And why would it cost that much to build such a machine, couldn’t it work just like a battery charger?
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### Author:  [@Mangetout](https://boards.straightdope.com/u/Mangetout)
#### Post date: [June 28, 2002, 1:34pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/7 "2002-06-28T13:34:11Z")
Since the lightning is sufficiently powerful to break down the insulating layer of air between cloud and earth, how would you stop it just jumping out of the capacitor?
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [June 28, 2002, 1:41pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/8 "2002-06-28T13:41:18Z")
> [@](#):
>
> \*Originally posted by Mangetout \*
> \*\*Since the lightning is sufficiently powerful to break down the insulating layer of air between cloud and earth, how would you stop it just jumping out of the capacitor? \*\*
You’d likely hook up multiple capacitors…each one taking whatever it can handle (which would not be enough to leap out of the capacitor till you wanted it to). Any excess energy your capacitor bank can’t handle you’d just dump into the ground.
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [June 28, 2002, 1:55pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/9 "2002-06-28T13:55:32Z")
> [@](#):
>
> \*Originally posted by DrLiver \*
> \*\*…a scientists was saying that some of the highest towers get hit by lightning several thousand times per year; wouldn’t that be enough to justify building a lightning ‘captor’.
>
> And why would it cost that much to build such a machine, couldn’t it work just like a battery charger? \*\*
It’s probably more expensive than you think. It’s not just the capacitors but the whole setup. IANAElectrical Engineer but I imagine your cabaling would have to be pretty serious. A lighting strike will provide a LOT of power in a very short period of time. You’d also have to build dozens of capacitor farms to collect energy all over the place. If I only had one hooked-up to the John Hancock building in Chicago I might get my capacitors charged up a few times during the summer so I still have to build power plants to supply all the energy chicago needs through half the year when lightning rarely if ever occurs in Chicago. Add in maintenance and such and the economics just don’t pan out. If it did I’m sure someone would have done it by now.
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### Author:  [@AndrewL](https://boards.straightdope.com/u/AndrewL)
#### Post date: [June 28, 2002, 2:14pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/10 "2002-06-28T14:14:21Z")
I _am_ an electrical engineer…
And I can second what’s been said. A lightning stroke represents a huge amount of energy in a tiny amount of time. Your capturing/charging device would have to be rated for the peak power level of the lighting strike, which is huge. If you want to actually use the energy in the lightning strike for any useful purpose, you’ll have to store it and play it out slowly. So, you’ve got less than a second of time to charge your power storage device. A capacitor is the only power storage device which can charge that quickly. Problem is capacitors suck at storing large amounts of power - their power density and cost-per-energy-stored is very poor compared with a battery or chemical fuel source. Furthermore, you’ll have to replace the capacitor bank periodically - they don’t last forever, especially with the violent charge cycles you’ll be subjecting them too. It’s just not cost-effective to gather energy this way.
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### Author:  [@Aro](https://boards.straightdope.com/u/Aro)
#### Post date: [June 28, 2002, 2:20pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/11 "2002-06-28T14:20:14Z")
**AndrewL,**
Would it be feasible then that is may become cost effective to collect energy from lightning if the cost of fossil fuels increased drastically? Is the science fully there, is it only money that makes it impractical?
Whack - I was being _ironical_
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### Author:  [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)
#### Post date: [June 28, 2002, 2:21pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/12 "2002-06-28T14:21:12Z")
On one of my ships, while I was in the NAv, we had an interesting piece of equipment… Essentially a huge-ass power supply filter. It contained some 0.5 farad caps (yes… 0.5), which were as big around as my thigh, and as long as my leg.
That’s only the smallest fraction of the size of the equipment you’d need to grab lightning.
To have a realistic chance, you’d need a capacitor, or bank of capacitors, several hundered times larger than the one I described above, possibly thousands of times larger. You’d need all the associated electronics; inverters, breakers, buss works, controllers, etc. to support this plant, and you’d have to place it close to the point of strike to ensure you capture the jolt before it went and did one of those weird and wonderful things lightning is capable of, such as jumping right out of your nice prepared conductors and finding it’s own way to earth.
So: We can build a system that occupies large volumes of industrial space in the high-rent districts of major cities, or way the hell out on top of mountains (where you’re most likely to get reliable strikes), that will cost _serious_ bucks, and likely be used about 5% (or less) of the time…
Yeah, we could do it, but… _why?_
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [June 28, 2002, 2:25pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/13 "2002-06-28T14:25:29Z")
Building a capacitor (or any other energy storage device) “big enough” is _not_ the problem. The problem is how to deal with a super high voltage. Designing a system to safely and efficiently harness energy from millions of volts is not a trivial thing…
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### Author:  [@Seraphim](https://boards.straightdope.com/u/Seraphim)
#### Post date: [June 28, 2002, 2:36pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/14 "2002-06-28T14:36:38Z")
IAEE too, and like Andrew said power collection would present a problem with such quick bursts of energy.
I finally googled up a [site](http://www.weatherwise.org/qr/qry.lightningpower.html) that lays out the straight dope. The main problems are (1) lightning doesn’t have as much energy as you think and (2) cost prohibitive to harnest it.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [June 28, 2002, 2:38pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/15 "2002-06-28T14:38:23Z")
> [@](#):
>
> \*Originally posted by Crafter\_Man \*
> \*\*Building a capacitor (or any other energy storage device) “big enough” is _not_ the problem. The problem is how to deal with a super high voltage. Designing a system to safely and efficiently harness energy from millions of volts is not a trivial thing… \*\*
Let me also add that “designing a system to safely and efficiently harness energy from millions of volts _over a few miliseconds_ is not a trivial thing…”
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### Author:  [@Squink](https://boards.straightdope.com/u/Squink)
#### Post date: [June 28, 2002, 2:39pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/16 "2002-06-28T14:39:53Z")
> [@](#):
>
> The energy of an average 3 mile-long lightning strike is one billion to ten billion joules. To keep a 100-watt light bulb going for one second, one hundred joules of energy will be used. With one billion joules, the light bulb will be lit for 116 days.
[http://van.hep.uiuc.edu/van/qa/section/Electricity\_and\_Magnets/Making\_Electricity/20011108073726.htm](http://van.hep.uiuc.edu/van/qa/section/Electricity_and_Magnets/Making_Electricity/20011108073726.htm)
> [@](#):
>
> if all the energy associated with a bolt of lightning could be captured and used, it would keep my house going for somewhere between half a month and five and a half months .
[http://www.weatherwise.org/qr/qry.lightningpower.html](http://www.weatherwise.org/qr/qry.lightningpower.html)
[How many slices of bread could you toast in a lightning strike ?](http://www.sciencenet.org.uk/database/Physics/9609/p00461d.html)
About 160,000 !
Here are some maps of [lightning bolt flash density](http://www.lightningsafety.com/nlsi_info/lightningmaps/worldlightning.html) NW Arizona looks like a good place to build a lightning powered city.
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### Author:  [@DrLiver](https://boards.straightdope.com/u/DrLiver)
#### Post date: [June 28, 2002, 2:47pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/17 "2002-06-28T14:47:13Z")
Thanks a lot guys,
So I guess my billion dollar lightning power company plans are out of question.
oh well…maybe I’ll find something else…
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [June 28, 2002, 3:53pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/18 "2002-06-28T15:53:03Z")
> [@](#):
>
> \*Originally posted by Squink \*
> \*\*NW Arizona looks like a good place to build a lightning powered city. \*\*
Actually in the US Florida would be your place of choice for a lightning powered city. Florida has WAY more lightning strikes than any other state in the US.
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### Author:  [@rabbit](https://boards.straightdope.com/u/rabbit)
#### Post date: [June 28, 2002, 4:44pm UTC](https://boards.straightdope.com/t/why-cant-we-capture-lighting/116370/19 "2002-06-28T16:44:58Z")
FWIW I remember reading about a couple plans (strictly “drawing board” stuff) to harness the power of lightning. Basically they would hook up lightning rods on skyscrapers to huge rotating discs (storing the energy as kinetic). The rotating disc being the size of a football field and nothing existing that could handle the centrifugal forces being some of the limitations of the idea.
Looking for cites now, but this was WAAAAY back in the late 80’s early 90’s (read it in either Popular Science or Popular Mechanics).