Hydrogen storage is a critical issue of hydrogen energy system in terms of safety and economics. Chemical hydrides are an attractive hydrogen storage method due to their potential of achieving high volumetric and gravimetric storage densities. Among chemical hydrides, sodium borohydride (NaBH₄) is given a big attention, due to its 10.8% theoretical hydrogen storage capacity. Hydrogen, which can be released by sodium borohydride hydrolysis reaction onsite, can be used in a proton exchange membrane fuel cell (PEMFC) at anode. On the other hand, sodium borohydride solution can be used directly in a direct borohydride fuel cell (DBFC) at anode.

Like the other chemical hydrides, sodium borohydride is an expensive material, constituting a major obstacle to commercialization of sodium borohydride as a hydrogen storage method. This paper aims to give an approximate process cost of a NaBH₄-H₂ system by taking into account both the energy and raw material costs, starting with, sodium borohydride production till recycling of it. In this paper, two different methods to synthesize sodium borohydride are analyzed and their effects on total cost are compared. It is found that the usage of Bayer process to synthesize sodium borohydride makes the overall sodium borohydride - hydrogen system cost higher than the total cost of the alternative process which starts with the production of sodium borohydride from borax decahydrate.