Optimising Solid Oxide Cells for Co-electrolysis Operation: Key Findings and Implications

Research by the Graz University of Technology has made significant progress in optimising the performance of Solid Oxide Electrolysis (SOE) systems, which are crucial for the production of hydrogen and syngas through the co-electrolysis of steam and CO2. The study employed a Design of Experiments (DoE) approach to investigate the effects of various operating parameters, such as current density, temperature, inlet gas composition, and flow rate, on the stack efficiency and behaviour of an industrial-scale electrolyte-supported SOE stack. The results showed that current density has a significant effect on the stack voltage, which is temperature-dependent, but has a minimal effect on the composition of the product gases. By optimising the operating conditions, the researchers were able to reduce the electrical power requirement by more than 7% without compromising the product gas composition or production rate. These findings have important implications for scaling up SOE technology for large-scale applications in clean hydrogen and syngas production, potentially improving energy efficiency and reducing operating costs in industrial settings.

Key Takeaways:

• The research used a Design of Experiments (DoE) approach to investigate the performance of an industrial-scale SOE stack during co-electrolysis.
• The study varied key parameters, including current density, temperature, inlet gas composition, and flow rate, to assess their effects on stack efficiency and behaviour.
• The results showed that current density has a significant effect on the stack voltage, which is temperature-dependent, but has a minimal effect on the composition of the product gases.
• By optimising the operating conditions, the researchers were able to reduce the electrical power requirement by more than 7% without compromising the product gas composition or production rate.
• The findings have important implications for scaling up SOE technology for large-scale applications in clean hydrogen and syngas production.
• The research concluded that optimising SOE stack performance can improve energy efficiency and reduce operating costs in industrial settings.
• Felix Muetter, a researcher from the Graz University of Technology, noted that the study provides valuable insights into optimising SOE stack performance.

Statistics:

• The researchers optimised the operating conditions to reduce the electrical power requirement by more than 7%.
• The study used advanced techniques such as electrochemical impedance spectroscopy (EIS), distribution of relaxation times (DRT), and spatial temperature profiling to investigate internal processes such as diffusion and polarisation losses.
• The research concluded that scaling up SOE technology can improve energy efficiency by reducing the electrical power requirement.

Sources:

• Optimising Solid Oxide Cells for Co-electrolysis Operation: Parameter Interactions and Efficiency Gains At Industrial Scale. Applied Energy, 2025;396.
• Elsevier Sci Ltd, 125 London Wall, London, England. (Elsevier - www.elsevier.com; Applied Energy - www.journals.elsevier.com/applied-energy/)
• Felix Muetter, Graz University of Technology, Institute of Thermal Engineering, Inffeldgasse 25-B, A-8010 Graz, Austria.
• Christoph Hochenauer, Vanja Subotic, Pavle Boskoski, and Stefan Megel, co-authors of the research paper.