Incinerators with significant veterancy buffs consume the same amount of energy as factory-fresh Incinerators, despite dealing more damage. I tested it with -25% reload: at that point it should consume 375 energy instead of 300.
#Incinerator energy cost doesn't scale with unit XP.
terse iron
vague zinc
Incinerator and Telchine don't get their reload scaling, I think. The sweepfire heatray weapon type is mostly scripted, right now, in the same place as the unit's animations (walking, turning, etc) are.