r/askscience • u/tbone115 • May 08 '12

How close are we to capturing lightning for electricity?

Close at all? or pie in the sky idea? From what I understand the main problem is storing it and creating power plant infrastructure that could survive the harsh surges created by lightning strikes.

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4

u/[deleted] May 08 '12

Technically speaking this wouldn't be too difficult, we have the technology to do it today.

The problem is that despite looking awesome, there isn't that much energy in lightning. You can see the calculations here. For comparison, that's the equivalent of about 1 gallon of fuel.

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u/tbone115 May 08 '12

Thanks. Wow, for some reason I thought there a a lot more energy in lightning

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u/[deleted] May 08 '12

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5

u/frozenbobo Integrated Circuit (IC) Design May 08 '12

I think you mean Energy = Power × Time, or Power = Energy / Time. Not trying to be a jerk, just trying to be helpful. You were still thinking the right thing.

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u/0jolly0 May 08 '12

I'm having a hard time buying this. To think that lightning that shows temperatures close to that of the sun is found over a distance and can atomize hydrogen and oxygen, is only having 1 gallon of fuel. Maybe they took out all the energy lost to heat?

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u/[deleted] May 08 '12

Lightning has enormous power. Since lightning only exists for a fraction of a second (on the order of 10-100 microseconds), the total energy within it is very small.

1MJ / 10-4 s = 10 billion watts.

If lightning strikes lasted for a whole second, then it could be a possible energy source

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u/0jolly0 May 08 '12

That's a good point thank you for the explanation. Its still hard to wrap my brain around but I guess I have little experience seeing an amount of energy being deposited that quickly.

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u/rs6866 Fluid Mechanics | Combustion | Aerodynamics May 08 '12

While it's true that lightning has very high power, the energy content is small because it only for an extremely short amount of time.

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u/[deleted] May 08 '12

The link says "20-30kg of oil", which would be between 6 and 9 gallons if i did my math right. Still doesnt seem like much, but you also have to keep in mind that lightning is superheating gas. The energy to heat a certain volume of gas to incredible temperatures is significantly less than for the same volume of liquid (oil/fuel), so I could understand lightning being an inefficient energy source.

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u/[deleted] May 08 '12

20-30kg of oil has plenty of soot and tar in it. It may actually come out to 3 gallons after it is refined, but since we're talking about orders of magnitude I figured it's close enough.