  A 6-cell solid oxide electrolysis stack was tested under H2O + CO2
co-electrolysis conditions. The cells used in the stack consisted of a
nickel-yttria stabilized zirconia (Ni-YSZ) fuel electrode, YSZ electrolyte and
lanthanum strontium cobaltite-gadolinium doped ceria (LSC-GDC) composite oxygen
electrode. The aim of this study was to investigate the stack durability when
operated under dynamic load conditions simulating a wind energy powered SOEC
stack for synthesis gas production. The degradation of the stack was observed
to be less than 1%/1000 h in terms of area specific resistance during the 1000
hours operation. Detailed electrochemical analysis revealed a constant ohmic
resistance, indicating intact contact in the stack. Only minor degradation was
observed, mainly due to the fuel electrode process. The overall stack voltage
degradation rate was 0.8%/1000 h.
