10 000 h Solid Oxide Electrolyser Stack Operation

10 000 h operation of a solid oxide electrolyser stack for highly efficient hydrogen production

A high temperature solid oxide electrolysis stack has been operated for 10 000 hours at 700 °C and -0.5 or -0.6 A/cm^2, showing a good durability. Within the FCH-JU project ADEL (ADvanced ELectrolyser for Hydrogen Production with Renewable Energy Sources, www.adel-energy.eu) with 13 partners, this durability test on a SOLIDpower stack has been performed by EIFER. The test was started at the end of the project ADEL. The short stack (6 cells, 300 cm^2 active area) was initially operated at 700°C, -0.6A/cm^2, 50% steam conversion. After 3200 h, the stack experienced an accidental water supply interruption, which degraded the stack. The test was then continued at -0.5 A/cm^2, 42% steam conversion and a partial performance-recovery was observed. During the subsequent 6000 h operation the stack showed no significant degradation, while the average operating voltages of all repeating units were in the range of 1.26-1.29 V. Thanks to this relatively low operating voltage in comparison to low temperature water electrolysers (typical operating voltage: 1.7-2.1 V), solid oxide electrolysers are the most efficient electrolyser technology available with electricity to hydrogen conversion efficiencies in the range of 85 to 95% (refers to the higher heating value of hydrogen).

Voltage evolution of all repeating units (RUs) in the SOLIDpower stack during the durability testing performed by EIFER.

Contact: Qingxi Fu Annabelle Brisse