Tell me more ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.
up vote 1 down vote favorite

According to Wikipedia an average lightning has 1TW, the whole world used 16TW in 2006. (I suppose this means the same as 16TWh in one year?) Sometimes the lightning reaches 100kA. This peak last for 30 microseconds. Does this mean that you get 100TW in 30 microseconds, and this is enough to power a 100 watts lightning bulb for two months, and that if the lightning lasted for about 1/6th of a year, it would have provided enough energy for the whole world?

share|improve this question
1  
According to Doc Brown (en.wikipedia.org/wiki/Back_to_the_Future), the energy contained is at least 1.21 gigawatts ;) – akid Jan 5 '12 at 8:10
1  
@akid: Jiggawatts is a measure of power, not energy. – endolith Jan 5 '12 at 21:27
Right! The linked wikipedia article states 1.2 GW energy though, and I'm not sure if it's actually wrong there or just citing a non-physical statement from the movie. – akid Jan 6 '12 at 9:05
related: Can energy be extracted from clouds?. – David Cary Jun 1 '12 at 16:16
why is everybody stuck to a number given in the sci-fi movie? Has anybody really calculated the energy theoretically or experimentally? – user9588 Jun 1 '12 at 18:03
show 1 more comment

1 Answer

up vote 5 down vote accepted

You are confused about units. Watt is a unit of power (energy/time), Watt-hour is a unit of energy. 16TW is an estimate of the continuous average power usage of the world - which is about 140,000 TWh each year. If the lightning has a peak power of 1TW for 30 microseconds, this corresponds to an energy content of about 8000 Watt-hours.

share|improve this answer
In order to power the world, you would need to collect the energy of around 500,000 lightning strikes each second. – user2963 Jan 3 '12 at 20:40
I understand the units and that, maybe I formulated it poorly... I mean, I suppose Wikipedia meant 1TW with 1kA. Then, when we get to know that there is 100kA in a lightning, there are 100TWh in 30 microseconds. And this means the same as 0.1kWh in 2 months, like the bulb. – Friend of Kim Jan 3 '12 at 20:41
1  
First of all, the current means nothing without a voltage specified. – user2963 Jan 3 '12 at 20:51
Wikipedia says that the peak power is 1TW, for a period of 30 microseconds. Punch this into google: "1 terawatt * 30 microseconds in kilowatt hour". You get about 8KWh. Your bulb will consume about 150 KWh over 2 months of operation. – user2963 Jan 3 '12 at 20:53
1  
@50ndr33, your last comment gives the strong impression that you don't understand the units. The values you're quoting are not consistent with each other. Perhaps you could read up on the definitions of power, current, and energy on Wikipedia or elsewhere, and feel free to ask questions on this site if there are parts that confuse you. – David Zaslavsky♦ Jan 3 '12 at 20:56
show 4 more comments

protected by Qmechanic♦ May 16 at 13:43

This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.

Not the answer you're looking for? Browse other questions tagged or ask your own question.