A power supply system according to the present embodiment is a control apparatus for a power supply system that includes a hydrogen power generator adapted to generate hydrogen using electric power supplied from a power generator and supply a load with electric power generated using the generated hydrogen, and a storage battery configured to be quicker in control response than the hydrogen power generator and adapted to get charged and discharged to offset excess and deficiency of the electric power supplied to the load from the power generator, the control apparatus including: an acquiring unit adapted to acquire information about remaining energy in the storage battery; and a controller adapted to control the hydrogen power generator so as to start generating electric power when it is expected, based on the information, that the remaining energy in the storage battery reaches a first threshold within a predetermined time.