SOC Systems Research Highlights at DLR

Kurzfassung

Within the DLR Institute of Engineering Thermodynamics, the Electrochemical High Temperature Processes group addresses SOC system challenges related to experimental validation and large-scale integration under realistic boundary conditions. Research activities span both SOFC and SOEC operation modes and include process system concept development, experimental investigations at stack and module level, transient system simulations, and the integration of SOC modules into full process system demonstrators. The test infrastructure spans from a pressurized stack-level rig to atmospheric and pressurized module demonstrators. Early-stage system layouts are developed in the Python-based steady-state framework CELESTE, while experimental campaigns are supported by the transient Modelica framework TEMPEST, enabling rapid development of operating and control strategies during system testing. Both tools will be released as opensource at the time of the conference. This contribution provides an overview of recent DLR SOC systems research highlights utilizing this toolchain: For SOEC applications, research focuses on the integration of steam and co-electrolysis into power-to-X pathways. System-level studies compared steam electrolysis and coelectrolysis routes for methane, ammonia, and Fischer–Tropsch synthesis, assessing how both operating temperature and pressure influence system efficiency, heat-integration potential, and methane formation. These studies are directly linked to pressurized stacklevel experiments, where methane recirculation in a pressurized co-SOEC–FT configuration was investigated as a process-intensification approach. Progressing toward module validation, pressurized steam electrolysis has been operated up to 20 bar in a dedicated 15 kWel module test rig under both direct-current and pulsed operation. For SOFC systems, activities address integration challenges in drivetrain applications, particularly in maritime and aviation contexts. The DLR-coordinated Nautilus project explored LNG-fueled SOFC-battery systems as low-emission alternatives to combustion engines on seagoing vessels. A module-level experiment demonstrated SOFC-battery coupling using a higher-level energy management system (EMS) to achieve load-following operation. Building on these results, a land-based system demonstrator combining a 60 kWel SOFC system with a 40 kWh Li-ion battery was operated using cruise-ship-derived load profiles, accompanied by comprehensive CO2 and non-CO2 emission measurements across all operating states. The presentation will highlight overall progress in these two system-oriented research pillars and discuss both the demonstrated system maturity and remaining challenges toward industrial deployment.