TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The hydrogen maintained in the reservoir is purified hydrogen product and is withdrawn from the reservoir at different rates during over time. The hydrogen is withdrawn from the reservoir at varying rates for generating electricity in a fuel cell. The hydrogen is withdrawn from the reservoir on an episodic basis for other purposes, and the capacity of the reservoir is sufficient to supply hydrogen to meet peak demands. A transition period exists during the changing of the rate of hydrogen generation from the first rate to the second rate, and the capacity of the reservoir is less than 2 times that equivalent to the incremental amount of purified hydrogen product that would have been produced during the transition period at the second rate less that which would have been produced during the transition period at the first rate. The reformate is subjected to carbon monoxide-reducing conditions prior to the pressure swing adsorption. The second rate of hydrogen generation is nil or at least 20 % of the first rate of hydrogen generation. The reforming is maintained within a predetermined temperature at the first rate of hydrogen generation and at the second rate of hydrogen generation by adjusting the amount of combustion providing heat for reforming. The combustion comprises the combustion of the purge stream and combustion of hydrocarbon-containing feed. The reforming is either steam reforming and the combustion provides heat through indirect heat exchange (preferably autothermal reforming) or comprises a partial oxidation of hydrocarbon-containing feed fed to the reforming and oxygen-containing gas is also fed to the reforming. The volume ratio of hydrocarbon-containing feed to oxygen-containing gas is adjusted to maintain the reforming within the predetermine temperature. The rate of hydrocarbon-containing feed to the reforming is the primary variable changed when changing the rate of hydrogen generation and the rate of oxygen-containing gas or hydrocarbon-containing fuel for the combustion is adjusted to maintain the reformer within the predetermined temperature, and the rate of production of purified hydrogen product stream is that produced at the given hydrocarbon-containing feed rate. The combustion of the purge is used to preheat the hydrocarbon-containing feed or oxygen- containing gas for the reforming. The reformate is provided at a pressure suitable for pressure swing adsorption by compressing the hydrocarbon-containing feed or oxygen-containing gas for reforming. The carbon monoxide-reducing conditions involves subjecting the reformate to water gas shift conditions including the presence of a water gas shift catalyst and in the presence of water to react carbon monoxide with water to produce a shift effluent containing at least about 0.1 vol.% carbon monoxide (dry basis), cooling the shift effluent to a temperature below 100 degreesC and removing condensed water from it. A reservoir of hydrogen generated by the reforming is maintained. A purge gas is used during the purge cycle of the pressure swing adsorber. The adsorber has at least four cycling beds such that at least one of which is undertaking adsorption, another of which is being purged, another of which is being re-pressurized and another of which is providing purge gas to the bed being purged. The bed being re-pressurized comprises a reservoir for hydrogen from the reforming.