Naked Science Forum
Non Life Sciences => Technology => Topic started by: syhprum on 30/07/2018 21:29:04
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I was recently caught in a massive thunder storm in Germany and saw massive bolts of lightning carrying tens of thousands of amps blasting down from clouds a few km high.
apart from being pleased they were not too close my mind turned to how much power was involved I understand the voltage runs to hundreds of MV so the peak power must be very large
Are there any figures published as to what it may be.
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The following link calculates it at around 10 billion watts: https://www.windpowerengineering.com/business-news-projects/how-much-power-in-a-bolt-of-lightning/:
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I wrote this article - "How do lightning and thunderstorms work (https://www.thenakedscientists.com/articles/features/how-do-thunderstorms-work)" - about 10 years ago as part of a myth-conception debunk on the possibility of powering a town with lightning strikes. It contains the relevant statistics that you are searching for; a quick re-check suggests that they are accurate and still valid.
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The article by Paul Dvorak refers to the voltage as 100 KV surely this is a misprint for 100MV.
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The article by Paul Dvorak refers to the voltage as 100 KV surely this is a misprint for 100MV.
Interesting catch. There is also this statement from this Wiki article: https://en.wikipedia.org/wiki/Harvesting_lightning_energy
A single bolt of lightning carries a relatively large amount of energy (approximately 5 billion joules or about the energy stored in 145 litres of petrol). However, this energy is concentrated in a small location and is passed during an extremely short period of time (microseconds); therefore, extremely high electrical power is involved. 5 billion joules over 10 microseconds is equal to 5×1014 (or 500 trillion) watts.
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The article by Paul Dvorak refers to the voltage as 100 KV surely this is a misprint for 100MV.
It's definitely wrong. The spark coil in a car is running at about 30 kV. Lightning potential is millions of volts...
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Quote from: syhprum on Today at 07:27:55
The article by Paul Dvorak refers to the voltage as 100 KV surely this is a misprint for 100MV.
It's definitely wrong. The spark coil in a car is running at about 30 kV. Lightning potential is millions of volts...
A lightning bolt can deliver 10,000 Amps for 10-20 μS.
The breakdown voltage of air is about 1MV per meter (and a little less in the rain).
- You may conclude from this that a cloud 1km high simultaneously has a voltage of 1GV and a current of 10kA.
However, when the lightning has ionised the air, the voltage drop across the plasma path is very low.
So there are two phases to the lightning stroke:
- Establishing the path from cloud to ground, where trailers reach out, leaving an ionised trail behind them; most of the 1MV/meter occurs in these trailers. But the current is very low in this phase
- Once an ionised conductive path is established, the current is very high, but the voltage drop in the main lightning bolt is fairly low.
Much of the energy dissipated by the lightning bolt must be distributed through a large volume of the cloud that is being discharged.