A hydrogen generator includes a cartridge including a plurality of thermal conductors each having an outer wall assembled together to form a housing. A plurality of fuel pellets provided on the plurality of thermal conductors. Each fuel pellet has a hydrogen-containing reactant that will react to release hydrogen gas when heated. The hydrogen generator also includes a compartment configured to removably contain the cartridge. The hydrogen generator further includes a plurality of heating elements disposed in the compartment such that each heating element is in thermal communication with one of the thermal conductors when the cartridge is disposed within the compartment to generate heat to selectively heat one or more fuel pellets to initiate a reaction to produce hydrogen gas.