In the past, Pokémon hasn't really made any effort to create effects that fit their attacks' names. On Shaymin-EX LTR, Synthesis, rather than healing, searches for Grass Energy. Warlord-EX's High Breaching puts it to sleep. Vicinity ROS's Me First can't be used on your first turn, but most likely will be used on your second turn.
EMP refers to numerous things, but I assume the one you mean is an electromagnetic pulse. According to Wikipedia, it's a burst of electromagnetic energy that is disruptive to electronics in the area. While Trainer cards could be viewed as the electronic equipment of a Pokémon game, and disrupting them could be like an electromagnetic pulse, Energy cards could also be viewed as such. By discarding them, you're slowing down your opponent, which could be seen as a disturbance to the electronic equipment.
As for the power level, it really depends on the Energy acceleration in Reggie's format. 4 Energy for 100 isn't great, and the secondary effect really doesn't matter against, say, Blastoise or Bronzong. But if Reggie has nothing like that in his format, the effect could be good and balanced for 4 Energy.
However, Reggie, you might want to change the Pokédex entry on Raichu.
EMP refers to numerous things, but I assume the one you mean is an electromagnetic pulse. According to Wikipedia, it's a burst of electromagnetic energy that is disruptive to electronics in the area. While Trainer cards could be viewed as the electronic equipment of a Pokémon game, and disrupting them could be like an electromagnetic pulse, Energy cards could also be viewed as such. By discarding them, you're slowing down your opponent, which could be seen as a disturbance to the electronic equipment.
As for the power level, it really depends on the Energy acceleration in Reggie's format. 4 Energy for 100 isn't great, and the secondary effect really doesn't matter against, say, Blastoise or Bronzong. But if Reggie has nothing like that in his format, the effect could be good and balanced for 4 Energy.
However, Reggie, you might want to change the Pokédex entry on Raichu.