As often as you like during your turn (before your attack), move a Energy card attached to 1 of your Pokémon to another of your Pokémon. This power can't be used if Venusaur ex is affected by a Special Condition.
This card seems to be heavily based on Base SetVenusaur, with their Energy Trans powers functioning mostly identically, and a similarly costly-yet-powerful Solarbeam attack.
Incidentally, of the three final evolutions of Kanto starters made into Pokémon-ex in EX FireRed & LeafGreen, this is the only one whose power and attack bear the same names as their Base Set counterparts.