Well, this is technically possible, and I had similar thoughts: use special batteries as input and outcome lightning-charged batteries that used as a fuel by the same building ⚡️🔋
But I'm afraid, this will break the simplistic idea of the mod: you have a huge accumulator with a rod that captures and stores electricity. You place it and forget about it. Instead, with batteries or any other energy-item, you will be able to collect and even transfer it, which doesn't seem quite realistic...
Anyway, I added this to the ToDo-list
. At the moment, I'm focused on a couple of other mods (Titans and new special one), after finishing 1st stable version of them I plan to come back to the Lightnings, and maybe I'll try experiment with this idea.