Lifespan evaluation and benchmarking of novel high temperature electrolysis stack prototypes scalable for industrialization

As demonstration of SOEC technology scales up beyond the MW, successful economic exploitation remains hindered by the small size and low durability of stacks, driving up manufacturing and maintenance costs, respectively. In an attempt to address these issues, Sunfire SE has developed a new generation of electrolyte-supported stacks based on a novel architecture. In this work, a 25-cell variant reached 11 kh of operation, while a 60-cell variant was operated for 9 kh. Comparing the results with that of the former stack generation highlights lower beginning-of-life temperature, ASR T-ref and temperature evolution rate leading to increased extrapolated lifetimes, in spite of higher current densities. Furthermore, to compare stack data acquired in different conditions, this work introduces a stack “usefulness factor” based on lifetime nominal production in thermoneutral conditions. With 3.2 ton H 2 per 30-layer stack, it increased by a ratio of 3.5 compared to the previous generation and should constitute a cornerstone in technology cost reduction.