The Sub Energy is an alien energy source that first appeared in Ben 10 vs. the Negative 10 (Part 1) it said to be 20 times stronger than the Sun, it's also said to have the energy to destroy an entire continent. Originally it was given to the Plumbers sometime in the past by grateful aliens they helped but it was deemed too dangerous to use and locked up. Driscoll managed to take it in and equip it to his Power Suit, he was able to use its energy to empower himself but Ben as Upchuck manged to rip it off and used it as an attack aimed at the sky and destroying the president's faces at Mt. Rushmore.
The Sub Energy can also be seen in Ben 10 Alien Force the video game and Vilgax Attacks.