Hydrogen technologies are becoming key enablers in the transition to a decarbonized energy system. Solid oxide electrolysis cells (SOECs), offering highest efficiencies among electrolyser technologies, are typically considered unsuitable for dynamic grid participation due to perceived thermal constraints. This work challenges that perception by demonstrating the feasibility and potential of SOEC systems to provide grid-relevant ancillary services while enabling their direct integration with renewable energy sources.

The study presents three major advancements. First, we introduce and validate advanced operating strategies enabling dynamic SOEC operation. In particular, pulsed electrolysis—alternating between open-circuit voltage (OCV) and thermoneutral conditions—allows decoupling of electrical loading from the thermal response of the system. Experimental results from a commercial multi-stack SOEC module reveal that by adjusting the on-phase duration, thermal gradients remain within safe limits while maintaining system responsiveness. This demonstrates that transient operation is feasible and now in the same dynamic range as PEMEL without compromising stack integrity.

Second, we explore the capability of SOECs to provide ancillary grid services. Using laboratory-based emulation of Fault Ride Through (FRT) scenarios, we test the module’s real-time response and recovery characteristics. The results confirm that SOEC systems can not only tolerate fast load changes if operated properly, but also support grid stability functions such as frequency and voltage control under defined operating strategies.

Finally, we showcase field data from the H2Mare flagship project, where an SOEC system was deployed offshore on a barge near a wind farm. This setup proves the technology’s robustness and viability in harsh environmental conditions, including marine exposure and motion-induced stress.

This research is based on laboratory and field data from a larger research initiative and industrial collaboration as well as simulation-based assessment of operating strategies and pulsed operation. It represents an original experimental investigation into advanced SOEC operation and its systemic integration potential.