Season two episode Morality Bites led Fans to believe Phoebe's third power was supposed to be electrokinesis oder the ability to generate electricity. Although it has never been confimed it is often assumed that in that alternate future Phoebe shown in Morality Bites received the power of electrokinesis. However it is also theorized that the ability she used to kill Cal Greene with was actually an advancement of her empathy power, i.e. passing on harming emotions through the medium of electricity. This would explain why she snuck up on him and aimed for the brain rather than just throwing a bolt of electricity at him as anyone else would with the power of electokinesis. It also exaplins why Leo kept telling the Charmed – Zauberhafte Hexen Ones in the future that Phoebe's power, singular, can kill now. At the time of Morality Bites she only had premonitions, therefore probably being the power they were referring to hinting that the power she used to kill Cal Green with had developed from her power of premonition and as we know her empathy power developed from her premonition power which means an advanced version of her empathy power that allowed her to kill with electricity (for the reason above) would technically mean that her first power could kill in the future. Since the part of "Morality Bites" that showcased her alternate future's power took place in 2009 (three years after the series' end) it is very probable that her Empathy power advances into the lethal power we saw her kill Cal Green with, that is if she ever regains her empathy powers.
Third Power
In season six she developed the power of empathy. Being an empath allows Phoebe to channel others' feelings. Since powers are tied with emotions and Phoebe can feel others' emotions, it eventually became possible for her to tap into their powers. It was possible that an advanced empathy power meant Phoebe could channel the powers of someone else in a larger radius. After gaining her empathy power, Phoebe became much Mehr powerful and could vanquish many demons with ease Von reflecting their own attacks back at them magically.
