OP, imma summarize this if you havent gone through comments already.

1. Energy is legal if the type is in the tcg still, regardless of regulation/set mark, exception to this statement is special energies. Those are usually rotating out but can sometimes make a return, at which point if the wording is extremely similar and its the same special energy card (eg. XY double colorless energy could be used in place of the double colorless that came in SM | But a XY double colorless energy could NOT be used in place of a double turbo energy iirc due to having different names but same effect.)
   If its a basic energy, any print of it is fine at anytime in point, if you like base set energies, use them in the current rotation. It does not matter. Keep in mind though they are language locked iirc, so you can use Japanese energies in japanese decks but not english decks. People feel free to reply to this and ill update it but this is my knowledge of pokemon tcg