why can’t we capture electricity from lightning?


why can’t we capture electricity from lightning?

In: Technology

Lack of predictability. Our issue isn’t the manufacture of power, it’s the extremely regular and consistent manufacture of power.

We can. It’s just not enough energy to be worth it.

The highest density of lightning strikes in the world is found in [central Africa](https://www.zotup.com/en/density-of-lightning-strikes.html), where more than 70 bolts strike each square kilometer each year. That’s equivalent to roughly one strike per city block per year, if we use San Francisco’s downtown street grid (where a square km is about 10 blocks by 7). Let’s be generous and use 100 bolts/km^2 per year, which might be reached by a few isolated and especially lightning-prone spots in central Africa.

Wikipedia [lists a number](https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)) of between 1 and 10 billion joules per lightning bolt.

So the energy we get is, at most, (100 bolts / km^(2)) * (10 billion J / bolt). That’s a trillion joules per year per km^(2), or about 114 million J/hour per km^(2). Or, in more familiar electrical units, about 32 kilowatts for each square km averaged over a year. And that’s if (a) we capture every bolt, (b) every bolt has maximum energy, (c) we capture the resulting electricity perfectly, and (d) we can store it perfectly without loss between strikes. A more reasonable number would be much lower, probably in the low single digit kilowatts at most.

A typical solar panel collects somewhere around 100 to 200 watts per square *meter*, or 100 to 200 *mega*watts per square km, on a sunny day – on the order of a thousand to a hundred thousand times more. They don’t operate at this full power all the time, of course, because of clouds and nighttime. But even in the cloudiest, most polar regions on Earth – the worst possible conditions for them – a solar panel is still more efficient at capturing power than a lightning rod would be.

(There are certainly engineering challenges to doing this, as well. But those could probably be overcome if it turned out to actually be worth it – which it isn’t.)

Lightning wants to get from the sky to the earth, which is right in front of it, and it’s always going to take the path of least resistance. If you want to catch it then you’re going to add resistance, which is just going to make it go yeah screw that route.

Lighting looks dramatic but it is an instantaneous burst of static electricity so not as powerful as it appears. But it is an interesting idea!