Uhh… roughly 30 strikes per minute, over 6 hours would be 10k lightning strikes, at 300 million volts and about a billion joules a pop… If you could convince the thunderstorm to only strike your collection device, and you could store it usefully, uhhh
It’s like… 3000 megawatt hours. A little less than that. Which is pretty substantial. A city in Australia or about a million people would use about half that amount in a day.
Buuuuuuut: that assumes 100% conversation of energy in a lightning bolt to energy in the system, that’s frankly not remotely possible. You’d be lucky to capture 10% usefully.