Can lightning be used as a source of energy? Is it possible to use lightning or thunder as a source of energy, with the help of dielectric breakdown and splitting?
 A: It is possible, but as far developing a lightning harvester, it's impossible.
First lightning has incredibly high power, roughly 5 GigaJoules over 10 MicroSeconds, comes to about 500 TerraWatts...thats a lot of power. And to be able to harvest it in any inductor, or step it down would be really difficult. There are alot of reasons for this, but it boils down the the fact that the Voltage of a lightning bolt varies a lot.
So what we can do is use the lightning for some raw energy which we then use to turn turbines, sort of like Coal or Nuclear at a very high level. But this is made almost impossible since we cannot predict where storms will be, and seeding storms is very expensive itself.
Moreover, much of the energy in a lightning bolt goes towards the ionization of its path, so by the time it gets to earth, there just is not all that much energy left, since as soon as we lose the potential required to generate the bolt (around 10 MicroSeconds), the conducting path just disappears.
There is actually a lot we still don't understand about lightning, trying to harvest energy from it is among many research topics currently out there, however we are not on he verge of building lightning powered cities quite yet.
A: The answer to you're question is both yes and no.(As of per 21st January 2021 - No(atleast for large-scale))
From attracting the lightning to converting it to useful energy it's just too expensive.
One may think that attracting a lightning is a child's play. And, infact yes, it is. Just erect a few metal rods and it's done. But to make it safe it will take a lot more complex machinery.
One of the main challenge to harvest lightning is the amount of energy it possesses. It is said that a lightning bolt carries almost $10^6J$ to $10^9J$. That is a lot of energy. And saying that doesn't mean that all lightning bolts have that amount of energy. They carry varying amounts of  energy. And that's released in a verrry short period of time(a few microseconds).
Next, we can't predict where the lightning's gonna strike (Hmm, maybe you can but they can't be used to predict individual flashes) . And, again one may think just build the structure somewhere near a place which gets a lot  of thunderbolts every year. But if you check the probability of lightnings at different places, you'll find that places near the tropics and mountains have got the highest probability of lightnings and constructing something like this over there is a waste of money.
And then comes the next problem- the charge of lightning. You never know whether a lightning is positive or negative. So, you have to make some other kind of adjustments to make sure you don't mix those up.
You can read this nice article by the MIT School of Engineering.
