Operational Framework for Large-Scale Power-to-X Plants Fed by Renewable Energies Incorporating BESS and Electrolyzer Degradation

Abstract

In this study, a large-scale power-to-X (PtX) plant powered by renewable energy (RE) sources for hydrogen (H2) production is modeled with hourly time resolution. The model integrates photovoltaic (PV), wind, and battery energy storage system (BESS) plants to ensure stable and reliable electrolyzer (ELY) operation under variable RE generation conditions. A new degradation model for lithium iron phosphate (LFP) batteries that incorporates both cycling and calendar aging mechanisms is proposed. The model is specifically tailored to high-power industrial BESS containers using real-world data from manufacturers. This model improves the accuracy of BESS lifecycle evaluation over the entire operational period of the project. In addition, an ELY degradation model is incorporated into the PtX operational framework. Sensitivity analysis of RE plant sizing shows that the plants must be oversized to minimize the levelized cost of H2 (LCOH), which can result in a substantial amount of curtailed RE power. The study further examines various BESS operating philosophies and grid connection modes to assess their effects on system performance, component lifecycles, and the LCOH. The results indicate that adopting different BESS operating philosophies can reduce the LCOH by 1.60% and 1.28% in on-grid and off-grid modes, respectively. The findings offer valuable insights and a simulation framework for the techno-economic feasibility, scheduling, operation, and long-term planning of large-scale PtX projects.