Galvanic Discharge

If a spell or ability with one or more targets states that you "may pay" some amount of energy , and each permanent that it targets has become an illegal target, the spell or ability won't resolve. You can't pay any energy even if you want to.

Some spells and abilities that give you energy may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't get any energy .

Energy counters aren't mana. They don't go away as steps, phases, and turns end, and effects that add mana "of any type" can't give you energy counters.