, namely the air electrode (anode) and fuel electrode (cathode) are physically separated by a dense electrolyte which also plays the role of electrical insulator. 
The working temperature of O=SOE can be controlled by stream of air fed to the anode side of the electrolyser. The amount was adjusted to keep the electrolyser working temperature at the level of 740\(^{\circ}\)C. The value was chosen, to make the comparison between H+SOE and O=SOE. In the case of H+SOE, there is no possibility to control the temperature in a easy way. Thus, this O=SOE temperature was set as the same os H+SOE.