A hydrogen generation system is disclosed that has a vaporization section receiving and vaporizing fuel along with water and passing the vapor to a reformer catalyst section heated by a combustor section which generates reformate gas and is fueled by off-gas from a H.sub.2 purification unit along with a combustion air source. The off-gas outlet feeds the combustor section in the reformer assembly to heat the catalyst section and the vaporization section. An H.sub.2 storage unit connected to the H.sub.2 purification unit pure H.sub.2 outlet receives the pure H.sub.2. The storage unit has an outlet selectively connectable to the reformer assembly process inlet during startup without the need for a spark igniter. The startup process includes generating heat in the combustor section of the reformer assembly by passing H.sub.2 from the H.sub.2 storage unit through the vaporization section, the reformer catalyst section, the H.sub.2 purification unit and through the off-gas connection to the combustor section, then introducing water and fuel through the vaporization section and reformer catalyst section to generate reformate gas when the system is warmed, passing the reformate gas through the H.sub.2 purification unit to the off-gas connection to the combustor section, and establishing a back pressure on the reformer catalyst section and vaporizer section to decrease the hydrogen flow from the H.sub.2 storage unit until the system is fully sustainable without addition of H.sub.2 from the H.sub.2 storage unit.