Can any unit be given energy?
Yes, any unit in the game (so far as I know) can be given an energy status bar. I believe all energy starts out at 50, and raises to 200 until upgraded, if there is an upgrade available for that unit/building. Hero units will usually end up starting with full amounts of energy, and upgraded to 250. Some people have had problems with SCUnit if they give a unit energy and permanent cloak, the energy either does not appear or begins to drain. This may be a problem with StarCraft and nothing we can fix.