A method (100) of optimizing at least a part of a hydrogen, H 2 , production plant (300), and a system comprising the at least a part of the hydrogen production plant, are provided. The method comprises obtaining a first set of data (110) associated with component categories (120a-c) comprising component category type(s) (130a-c). The first set of data comprises a first and a second subset (150, 160) associated with a capital expenditure, and am operational expenditure, respectively, of each component category type. The method further comprises obtaining a second set of data (180) and a third set of data (190) associated with a cost of electrical power and ancillary service(s), respectively, and determining (200) the at least a part of the hydrogen production plant by a combination of the component category type(s) based on optimization criterion(s) (250) as a function of the first, second and third set of data.