Techno-Economic Evaluation of Islanded Electrolysis-Based Ammonia Production: A Western Australia Case Study

Abstract

Green ammonia is a promising energy and hydrogen carrier and a potential building block in a future, sustainable energy and raw material system. However, the production process requires a high amount of renewable energy. Since potential sites are most often located in remote areas with insufficient grid connection, islanded concepts based on intermittent renewable power generation are receiving a lot of attention. For such concepts, the part-load behavior of the applied electrolysis technology is of major importance for cost-effective operation. Within this study, a techno-economic evaluation of an islanded electrolysis-based ammonia production for a Western Australian location is performed. A special focus is laid on different part-load scenarios accompanied by a comparison of different electrolysis technologies. For this purpose, an extensive process simulation integrating electrochemical cell models as well as considerations of different turn-down capabilities is presented. The results indicate a superior efficiency of solid oxide electrolysis (SOEL) with up to ηprocess = 64.3% in full load operation compared to ammonia production based on proton exchange membrane electrolysis (PEMEL) only achieving ηprocess = 56.0%. Even in scenarios with high shares of part-load operation, SOEL allows for an efficiency of ηprocess = 63.3%. From the subsequent economic modeling considering development of electrolyzer equipment costs and stack lifetime for future scenarios, net production costs (NPC) for islanded ammonia production were derived. With NPC = 1084 US$/ (Formula presented.) for application of PEMEL and NPC = 1191 US$/ (Formula presented.) for solid oxide electrolysis, islanded green ammonia production was found to be economical feasible in the mid-term, highlighting the resilience regarding production cost and high planning reliability compared to conventional ammonia production.