As part of the Real-SOFC Integrated Project of the European Commission, four SOFC stacks each with 2 planar anode-supported cells were operated for durations of up to 3000 h under varying fuel and electrical load conditions. The variations comprised the external applied current density (0.3 or 0.5 A/cm²) and the fuel gas (hydrogen or methane). All stacks were operated galvanostatically at a temperature of 800 {degree sign}C and a fuel utilization of 40%. A pronounced difference in degradation behaviour was observed between the two stacks operated at 0.5 A/cm² and those operated at 0.3 A/cm². The latter displayed linear behaviour of the voltage with time over the full duration of operation. The degradation rate was always below 1%/kh. From the start, the two stacks operated at 0.5 A/cm² showed an increased degradation rate (> 2%/kh). Post-test characterization of the cathode with respect to chromium poisoning was performed on cells from all four stacks. Segments of the cells were cut by sawing and examined. On the one hand, polished samples for SEM characterization were prepared for microstructural and EDX investigations, and, on the other hand, the cathode was removed and chemically characterized with respect to compositional changes due to the incorporation of species from the surrounding components.