NOVELTY - The method comprises performing a first reaction including combining oxygen-containing gas, hydrocarbon and steam and producing a first mixture, where the first mixture contains hydrogen and carbon monoxide, performing a second reaction including combining steam and the first mixture and producing a second mixture, where the second mixture contains hydrogen and carbon dioxide, and performing a third reaction including membrane separation of hydrogen from non-hydrogen ingredients of the second mixture to produce a permeate hydrogen stream and a retentate stream.    USE - The method is useful for chemically processing a hydrocarbon to produce a hydrogen stream (claimed) that is useful as a fuel for a fuel cell, where the hydrocarbon includes methane, ethane, propane, organic waste, gasoline, diesel fuel, oil, coal, methanol and ethanol.    ADVANTAGE - The method ensures efficient and economical production of the hydrogen stream with high purity and safety.    DETAILED DESCRIPTION - The method comprises performing a first reaction including combining oxygen-containing gas, hydrocarbon and steam and producing a first mixture, where the first mixture contains hydrogen and carbon monoxide, performing a second reaction including combining steam and the first mixture and producing a second mixture, where the second mixture contains hydrogen and carbon dioxide, performing a third reaction including membrane separation of hydrogen from non-hydrogen ingredients of the second mixture to produce a permeate hydrogen stream and a retentate stream, performing a fourth reaction including oxidation of the retentate stream for producing hot and pressurized gas, rotating a shaft using heat and pressure of the hot and pressurized gas to drive the shaft using a turbine mounted on the shaft, producing energy and compressed air, where: the energy is produced using the turbine and a generator connected to the turbine; and compressed air is produced using a compressor mounted on the shaft, and maintaining a constant pressure of the permeate hydrogen stream on an ongoing basis at a permeate pressure setpoint using a master controller or computer and five subordinate controllers or computers, where: the subordinate controllers control subordinate setpoints; each subordinate controller independently controls a different one of the subordinate setpoints; a first subordinate setpoint represents a flow rate of the oxygen-containing gas preceding the first reaction; a second the subordinate setpoint the represents a flow rate of the hydrocarbon preceding the first reaction; a third subordinate setpoint represents a flow rate of the steam preceding the first reaction; a fourth subordinate setpoint represents a flow rate of the steam preceding the second reaction; a fifth subordinate setpoint represents a speed of the shaft rotation; use of the master controller and the five subordinate controllers includes accessing control data contained in the master controller; the control data establishes a relationship among the five subordinate setpoints and three optimal output levels of the permeate hydrogen stream; the optimal output levels vary in the relationship on a scale from zero output of the permeate hydrogen stream to maximum output of the permeate hydrogen stream; and each the optimal output level in the relationship has a corresponding group of the five subordinate setpoints. On the ongoing basis, a pressure sensor transmits sensory signals to the master controller, the sensory signals is indicative of the pressure of the permeate hydrogen stream, and the master controller processes the sensory signals in relation to the control data so as to determine the optimal output level resulting in restoring the pressure of the permeate hydrogen stream to the permeate pressure setpoint and so as to determine the group of the five subordinate setpoints that corresponds to the determined the optimal output level.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a fuel cell reformer system.