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, which is 4,739,085.6 BTU or 1.388MWh of energy.
Of course, not every lightning strike is the same; some are weak, and some are much, much stronger, but we can take that average number for continuing our approximation.
In the article, “How Much Would it Cost to Replace All Energy Sources with Solar?,” we already calculated that the world’s energy requirement for the entire year in 2030 will be 212,970TWh or about 727 quadrillion BTU.
So let’s calculate whether we could power the world on lightning strikes.
The website blitzortung.org *1 tracks lightning and thunderstorms in real time, and here are 3 recent days from the archive:
19/06/2016 (320,000 strikes),
18/06/2016 (365,000 strikes),
17/06/2016 (390,000 strikes) *2
The average here is around 350,000 strikes per day. 365 days * 350,000 = 127,750,000
But, we need to take into consideration that blitzortung.org does not have a network of sensors covering the entire planet (especially not over the oceans), so I will use other sources National Oceanic and Atmospheric Administration and Wikipedia, *3 *4 which says that there are 44 lightning strikes each second, so we can calculate that there are:
365 days * 24 hours * 3600 seconds * 44 strikes = 1,387,584,000 lightning strikes a year.
212,970TWh (total energy needs) /1.388MWh (single lightning bolt) = 153,436,590,000
1,387,584,000 / 153,436,590,000 = 0.9%
The total number of lightning strikes accounts for only 0.9% of our total energy needs.
As we can see, lightning bolts are not an energy source that can satisfy our energy needs, even with the 50% increase projected, because of global warming *6. It will still not become significantly more interesting.
Additionally, there are a few technical obstacles that make this type of energy unattractive for energy investment, regardless of its powerful appearance.
First, it is very difficult to predict where a lightning bolt is going to hit and it even more difficult for any device to withstand the huge surges of energy created by each strike. Even if we could to that, it is even harder to store that energy to use it later.
And, even if we somehow managed to overcome the problems of collecting, storing, and converting the energy from lightning to make it useful, we would still only harness a small fraction of the lightning strike power.
Being fascinated by idea of taming lightning, scientists invented several approaches to do that, out of which maybe the oldest one known is Benjamin Franklin's kite experiment. *8
In a more advanced approach, scientists have tried using lasers to ionize a column of gas that guides lightning *7. The approach has yielded interesting results, which probably cannot be used for harvesting energy, but this could prove a viable solution for protecting our buildings and equipment from sudden lightning strikes.
Regarding harvesting, there are some approaches that are not tested and exist as theoretical ideas. I will try to write about them, as soon as I get some experimental data showing any positive results.