Technology

Solid Oxide Electrolyzers (SOEs) constitute an advanced concept enabling Water, or rather, Steam Electrolysis at hhigh temperatures (600°C–900°C), which results in higher efficiencies compared to Alkaline or PEM Electrolyzers [89]. Nevertheless, this concept is not new; pioneering work on Solid Oxide Electrolyte Steam Electrolysis dates back to the end of the 1960s mainly in the United States and Germany. It is also relevant that much of the information available on SOEs has been obtained working with Solid Oxide Fuel Cells (SOFCs) operated in the reverse mode.

Whereas high-temperature Operation reduces the Cell voltages and increases the rate of the Electrochemical Reactions, it implies remarkable challenges as concerns thermal stability of the Materials and sealing issues. Moreover, the Stream leaving the Cathode is a mixture of Hydrogen and Steam that requires further processing which results in significantly higher capital costs of SOEs compared to conventional Liquid Water Electrolysis.^[1]

1. Ursúa, Alfredo et al. “Hydrogen Production From Water Electrolysis: Current Status and Future Trends.” Proceedings of the IEEE 100 (2012): 410-426.