Network modeling of future hydrogen production by combining conventional steam methane reforming and a cascade of waste biogas treatment processes under uncertain demand conditions

Our goal in this study was to design a hydrogen supply network to efficiently produce and manage hydrogen in case future hydrogen demand increases. Sludge from wastewater treatment plants can be converted into biogas using an anaerobic digestion process, and the generated biogas can be transformed into biomethane by amine technology as a biogas upgrading method. A cascade of four-associated technologies (COFAT) is developed in the proposed model as biomethane is converted into hydrogen by employing a biomethane-based steam reforming process. The suggested COFAT system which is not dependent on fossil fuels is integrated with a conventional steam methane reforming process and harnesses large amounts of hydrogen. Hydrogen management is performed using a hydrogen storage tank to meet regional hydrogen demand, and a hydrogen transport network is constructed using pipelines to transfer hydrogen between different regions. A dual-objective two-stage stochastic mixed integer linear program was used as a mathematical model to minimize the costs and downside risk simultaneously, and uncertain hydrogen demand conditions were included. A case study of the Gyeongsang-do province in the Republic of Korea was used in the proposed model, a 24% reduction in the total costs and a reduction of 94 tons of CO2 eq of carbon emission per day were realized for the proposed hydrogen supply network assuming the present hydrogen purchase price of 3.5 US$ per kg. We believe that the results provide reasonable solutions for the construction of a future hydrogen supply network.