It is only a bit more exothermic, about 20% more (again from my rusty enthalpy calculations). The downside of course is making the peroxide in the first place.

It is only a bit more exothermic, about 20% more (again from my rusty enthalpy calculations). The downside of course is making the peroxide in the first place. Also, peroxide is relatively safe (compared to gaseous hydrogen) to handle up to ~150C.