Performance assessment of a 25 kW solid oxide cell module for hydrogen production and power generation

Hydrogen produced via water electrolysis from renewable electricity is considered a key energy carrier to defossilize hard-to-electrify sectors. Solid oxide cells (SOC) based reactors can supply hydrogen not only in electrolysis but also in fuel cell mode, when operating with (synthetic) natural gas or biogas at low conversion (polygeneration mode). However, the scale-up of SOC reactors to the multi-MW scale is still a research topic. Strategies for transient operation depending on electricity intermittency still need to be developed. In this work, a unique testing environment for SOC reactors allows reversible operation, demonstrating the successful switching between electrolysis (−75 kW) and polygeneration (25 kW) modes. Transient and steady state experiments show promising performance, with a net hydrogen production of 53 kg day−1 in SOEL operation with ca. −75 kW power input. The experimental results validate the scaling approach since the reactor shows homogenous temperature profiles.