IIIIIt's very complicated power explanation time!
I'll simplify it real short for you, basically it's soul magic that allows him to do pretty much anything short of bending reality. Current energy was bestowed upon him by his master Nolan Kairo, the strongest (and only) modern Current user apart from Colt.
Current lets him do many things like enhancing his physical abilities far beyond what should be possible, nearly godlike strength, agility, reflexes, nigh-immortality that includes fast passive regeneration, various kinds of energy attacks and temporary constructs made entirely from said energy.