This work reports on the estimated performance of double layer electrolyte cells consisting of one gadolinia doped ceria (GCO) supporting layer covered by one yttria stabilized zirconia (YSZ) electron blocking layer. The latter might be located either on the cell cathode or anode side. Cell characterization includes estimates of the open circuit oxygen permeability and voltage deviation form pure Nernstian behaviour, and on the open circuit and shorted circuit electrolyte/electrolyte interfacial oxygen partial pressures. These parameters were estimated based on materials electrical properties (ionic, n-type and p-type conductivities), assumed layers thickness (50-200 mu m for GCO and 10(-3) to 10 mu m for YSZ) and cell operating temperatures (800 and 1000 degrees C), at constant oxygen partial pressure boundary conditions (0.21 and 10(-20) atm). The electron blocking characteristics of YSZ layers is demonstrated for both cell configurations, and possible advantages of both concepts are discussed.