Low-cost hydrogen production: Techno-economic analysis of high-temperature porous electrode membraneless electrolysis

Alkaline water electrolysis is a mature technology for large-scale hydrogen production that uses a membrane or a diaphragm to stop gas crossover. However, this membrane, introduces high ohmic resistance, limiting the cell operating conditions, while being relatively expensive. Membraneless electrolysis is a relatively new technology in which the membrane is removed, and gas separation is achieved by active or passive fluidic forces. In this study, by leveraging the potential advantages of membraneless technology including high-temperature and high-pressure operation, a techno-economic analysis is performed to evaluate the thermal and economic performance of a hydrogen production plant based on the flow-through porous electrode membraneless technology. A mathematical model was developed by considering the cell electrochemistry, fluid mechanics of porous electrodes, the thermodynamics of hydrogen system, and the economics of the plant's life cycle. A sensitivity analysis was carried out to estimate the levelised cost of hydrogen, LCOH, under different scenarios and provide a detailed assessment of the performance of this technology. It was observed that a membraneless technology operating at its peak has the potential to reduce the LCOH by some 36% in comparison with a conventional alkaline electrolyser cell. It was also shown that the proposed membraneless electrolyser can potentially produce hydrogen with an overall energy efficiency of up to 82.3% while delivering a purity of 99%. In future assessed scenarios, namely 2030 and 2050, it was also predicted that the LCOH of this technology can reach 2.56 and 1.18 $/kg, respectively.