The waiting list is at the beginning.
Mechanically, there is no flaw of Power Source. This flaw isn't very disabling; all it requires you to do in combat is to teleport, which is not much of a sacrifice. Outside of combat, it isn't a flaw at all. Further, it adds unnecessary complication to the game, since you have to keep track of rounds active. Compared to Slow, where it takes an extra half action to do all of your powers, the Power Source flaw only requires you to use one half action every ten rounds, assuming you weren't going to T-Port anyway.
Flavorwise, nothing prevents you from claiming that you have to teleport to activate your powers, but that disadvantage isn't really worth any points.