An energy utilization apparatus includes: an endothermic reaction device
for performing dehydrogenation endothermic reaction of an organic
compound; a compression device for pressurizing a first gas containing
hydrogen and a dehydrogenated organic compound, and a non-reacted organic
compound which are produced in the endothermic reaction device; a
distillation device for distilling under pressure the first gas which is
pressurized by the compression device, so as to separate the hydrogen and
the dehydrogenated organic compound from the liquefied non-reacted
organic compound; a vaporization device for vaporizing the liquefied
non-reacted organic compound by pressure-relieving; and an expansion
energy recovery device for obtaining power of the compression device by
using expansion force generated by the vaporization.