Disclosed is a method for producing a metal borohydride and/or H2, including: A. producing a metal borohydride in a synthesis process, in which H2 is a reactant and the reaction further takes metal hydroxide and boron oxide or further takes metal boron oxide; B. producing H2 in a chemical reaction process, in which metal borohydride produced in step A and H2O are reactants, the amount of H2 produced in step B being larger than the amount of H2 required as a reactant in step A for the same amounts of metal borohydride as a reactant and a reaction product in steps B and A, respectively; and C. providing H2 produced in step C to step A, and repeating steps A, B and C. Part of the metal borohydride and/or H2 is withdrawn while leaving an amount of metal borohydride and H2, respectively, so as to allow repeating steps A-C.