High Temperature Electrolysis at EIFER, Main Achievements at Cell and Stack Level

The European Institute for Energy Research is working on the application of the solid oxide cell technology for high temperature electrolysis with the aim to produce hydrogen and syngas. Since 2004, numerous tests of single cells and stacks with 5 to 25 cells have been conducted. Test durations were rather long, ranging from 1000 to 9000 hours, with current densities between 0.4 and 1 A/cm2. A summary of the experimental results is presented with a focus on the observation of cell and stack degradation. Long term operation of cells with 45 cm2 active area under a high current density of 1 A/cm2 indicates an extrapolated cell lifetime of at least 20 000 h. Cell integration into short stacks shows additional constraints such as non-homogeneous cell behavior, electrical contacting resistances of the cell interconnects which are more critical under operation at high current density, and increased degradation rates.Techno-economical analysis have been realized in parallel to establish the hydrogen production cost by high temperature electrolysis as function of the electrolyser environment (availability of an external heat source, electricity source, hydrogen compression stages.). Finally, the hydrogen production costs using high temperature electrolysis are discussed and the high temperature electrolysis is positioned on the roadmap of development and deployment of the electrolysis technologies for hydrogen and syngas production.