Current JP is unable to control his powers like he could in the past. As of now he just endlessly absorbs ambient energy from his surroundings, which builds up until he inevitably detonates (seems to happen every 8hrs or so.)
Steel has JP on a strict schedule, where he is regularly Boom Tubed to a moon of Mars, allowed to safely detonate, then returned back to Earth:
*He's done that 68 times so far.
Anyway, I haven't kept up with Shaw, so his abilities/limitations may have changed, but a kablooey from JP seems like it would overload him at the very least.