How many volts are in a lightning strike?

An inquisitive reader recently asked a curious question on Facebook: Does a bolt of lightning provide enough energy to power a town? I don’t know, but there is a way to get a fair estimate. Let’s find out how many volts are in a lightning strike:

how many volts are in a lightning strike

The bolt shows a little of the great complexity in lightning. To capture the energy, put your super-super capacitor right in the strike zone.

From articles in Windpower Engineering & Development, we learn that lightning bolts carry from 5 kA to 200 kA and voltages vary from 40 kV to 120 kV. So if we take some averages, say, 100 kA and 100 kV, this bolt would carry this much power, P:

P = 100×103 A  x 100 x 103 V

= 10,000 x 10VA or Watts

= 1 x 1010 Watts

Recall that 1010  Watts is 10,000,000,000  or 10 billion Watts.

Now assume this energy is released in 1 sec. So the power is:

1010 W-sec. On your electric bill, you’ll see you pay for Watt-hours or Wh. So let’s convert W-sec to Wh:

Pl = 1010 Ws x 1 hr/3600 s

Pl = 1/36 x 108 Wh

= 0.0277 x 108

= 2.7 x 106 Wh or Watt-hour per our average lightning bolt.

But can that power a town?  And if so, for how long?

How much power does a single house consume?  Again we have to play with averages. So let’s assume one house needs 2,000 Watts/hour to keep the frig, furnace, computer, and all things plugged in going. In one day, 24 hours, the house consumes

Ph = 2,000 Watts x 24 hr.

= 48,000 Wh

So if we divide the power draw for the house into the power of a lightning bolt, we’ll have the  number of houses that bolt can power:

N = 2.7 x 106 Wh per bolt / 4.8 x 104 Wh/house

= 0.5625 x 102

= 56 houses/bolt of lightning for one day.  So the answer to the original question is that a big bolt could power a small, 56-house town for a day.

That assumes we can catch all of that average bolt of lightning in a large capacitor. If you assume a capture efficiency, that would add a few more calculations. Still, the original question is intriguing.

If you wish to take this math experiment a step further, consider how often the U.S. is struck with lightning each day. NOAA online says 22 million cloud-to-ground strikes per year.

If any of you EEs would like to comment or correct my assumptions or math, I welcome you to do so.

–Paul Dvorak

Comments

  1. I’m not sure. You might fly a kite in an electrical storm with a wire attached to the capacitor and the other lead to ground. It’s just a concept.

    Paul

  2. is it possible to store lightning energy in a large capacitor??
    ?

  3. John Fowler says:

    Hey Paul or anyone else out there – I need help. I was told that a 1.5 Vdc AA battery contains 15 joules of energy and can produce 300 volts after charging a disposable camera flash capacitor. Is it wrong that I divided the 300 volts by 15 joules and came up with the number 20, then was able to assume that if I had a heart defibrillator, containing 500 joules of energy could produce 10,000 volts? i.e.20 X 500 = 10,000 v. Am I using funny math?

    Also, if a thermoelectric generator was placed into a stationary orbit in space to absorb 2,000 degrees F and use a capacitor to amplify and store that energy, what would the voltage capacity be? Then, if that voltage was stored into a capacitor to multiply the voltage, what would it be?

  4. Good evening.

    I have experimented with high voltage my entire life. You have a great article here, but a bolt of lightning only 40kv to 120kv? That is not accurate at all. On my kitchen table is a device that produces 300kv and the Sparks are only 8 inches long….to put things in perspective. Lightning is known, as a standard, to have a voltage potential of 100million volts. Air’s dielectric breakdown limit is 3.0 million volts per meter. This is a well studied number. The electric field under a storm allows the bolt to penetrate through more air than normal. so, your calculations are slightly underpowered. Replace 120kv with 100million volts.

  5. William says:

    There is elecromagnetic energy all around us. Try placing a grid of copper wires above ground with one end grounded and the other end to a transformer.. You will get volts…

  6. But i didn’t get charles klasky explanation of the bolt storage method he said can anyone give more oil to the hair and if by any chance i need to discuss with you about the bolt stuff can i get your email pls

  7. charles klasky says:

    One possible way to store the energy from a bolt of lightning might be to use electromagnetism and gravity, one of the oldest kinds of “battery” the thing that powers your old grandfather clock. If the tower that attracted the lightning (and was well insulated from the ground) had a coil that directed that charge to ground, and if it had a heavy solid magnet in the middle of that coil, then the electricity would raise that magnet as the charge went down the down the wire. The same king of brake as you find in a standard elevator would prevent that weight from falling striaght back down again. That potential energy would be stored energy as long as the great bolt can be efffectively shunted to prevent from daining that energy off with it..
    Using the top of the tower as a mast for high flying (Ben Franklin) kites could get that conductor much higher into the storm clouds. Mulitiple directionalble kites could spread the collection area out both vertically and horizontally. That way it could collect more positive ions from the storm cloud.
    This way the charge could be collected gradually. The point is not to force a violent discharge but to collect the energy from the system befoere it happens.
    Of course the number of negative ions in the ground will always be one limiting factor but radio towers already spread out huge wheels of grounding wires to dissipate lightning energy- to prevent damage to the radio equipment, cell phone electronics and more. This is a well understood and a well developed technology. If nothing else I believe this possible technology should be studied to provide -if nothing more – emergency power for areas afflicted by storms. You could even use that energy to pump water.
    There are tens of thousands of towers already erected (from existing high voltage power towers to cell phone towers) that could be potentially retofiited with a system that collects the energy of lightning. I don’t know if this idea is feasible or even possible. I also have no idea how such an extraction of this energy might affect the storms that produce them – possitively or negetively. At any rate if we actually started to develope this technology it would most likely be at a slow enough pace for us to to be able ask and answer those questions long before they become crises events. Please let’s move forward.

  8. kalaiyarasan says:

    if we can find a capacitor to save the lightning power its enough to use allover the world without powercut for next 5 years…………

  9. Although a single strike of lightning does last a mili-second many lightning discharges have multiple discharges called dart leaders.

  10. archaeopteryx says:

    Methinks that strapping an alternator around the equator is a better idea and we will skip the capacitors

  11. > If 10,000,000 watts is Ten Mega-watts, does that make 10,000,000,000 watts Ten “Biga-watts”?

    No, that’s 10 TERROR watts.

    10,000,000,000,000 is 10 DOOM watts, by the way 😉

  12. Hi,

    Just a small technical point – Wh (or W-sec) is a unit of energy, not power.

  13. Hi paul,
    Keith brought up a really good point. He’s actually right about lighting only lasting a milli second. That would actually bring ur calculation to somethin like 2.7 x 10^4 or something. Either way, i think a lighting bolt only has enough energy to power on 1 single lighting bulb, for 3 or 4 months. The amperage just isnt there….

  14. Thanks to all of you for the comments. As you all recognize, this is just a paper experiment to get a handle on the power in a lightning bolt. Although lightning bolt is dangerous, we can conclude, it does not carry much energy. In my calculations, I assumed 100% capture efficiency. That is just not practical. Nonetheless, it was fun to “run the numbers.” –Paul Dvorak

  15. Paul – your calculation for energy used by a house is very good. Most homes in the USA use around 1,000kWh to 2,000kWh per month – that is, about 33 to 66 kWh per day (1kWh = 1,000 Watt-hours). The average cost in the USA for a residential service is around $0.10 per kWh, so the average bill is around $100-$200 per month for energy. Most if not all utilities also have an additional fixed charge (pays for the poles, wires, transformers, breakers, power plants, employee wages, etc.) that is also on the monthly bill.

  16. I didn’t go thru your math, but I did note that you made the assumption that the lightning bolt last for 1 second. Actually, the electrical charge is transferred in a few milliseconds (thousandths of seconds). If you search Wikipedia for “Harvesting Lightning Energy” there is a discussion there that is fairly accurate, I think. A quote from that Wikipedia article: “According to Martin A. Uman, co-director of the Lightning Research Laboratory at the University of Florida and a leading authority on lightning,[6] a single lightning strike, while fast and bright, contains very little energy, and dozens of lightning towers like those used in the system tested by AEHI would be needed to operate five 100-watt light bulbs for the course of a year.” footnote 6 = ^ Uman Receives 2001 Fleming Medal. http://www.agu.org.

    I’m not saying that it can’t be done, or it can’t be done efficiently, but with any current technology, it is not practical. I don’t want to discourage anyone from trying to perfect this technology. What can’t be done is to ignore any laws of physics, which is commonly done by “the average guy” tinkering in his garage/shop, who doesn’t fully understand all the engineering, but tries to design something anyway. Those things usually either work only once, or don’t ever quite work. Close doesn’t always count, you know.

  17. 40 kV to 120 kV?

    Yes, 40,000 to 120,000 V and I would not be surprised if it were more. I picked 100,000V to work with because it’s a round number.
    –Paul Dvorak

  18. Thanks a lot for the calculation.
    Although it’s a good idea to use the energy of lightning bolts, but the major problem is the harvesting method.
    In my opinion, we have still a long way to achieve the technology. Although it is not impossible!

    Danyar:
    You are absolutely right in that capturing a bolt or even part of it requires a mystifying method. But I have to think there are more than a few people who have considered the problem. If it were easy, it would have been done by now.
    –Paul Dvorak

  19. If 10,000,000 watts is Ten Mega-watts, does that make 10,000,000,000 watts Ten “Biga-watts”?

    Max:

    Do you always think big? To you question, yes, 10 Berry Biga-watts.
    –Paul Dvorak

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