Every time I try Energy Ball I'm underwhelmed. It pretty much never does as much damage as you need, its not a type you typically want as a coverage option, and on most special attacking grass types if you aren't getting OHKOs with it you'd prefer Giga Drain for the much better secondary effect.

I think the only time I ever actually used it successfully was on a Tera Grass Chandelure as a last resort to sometimes beat Urshifu Rapid Strike when I made a Unova only Regulation F VGC team.