Analysis of self-sustaining recuperative solid oxide electrolysis systems

The generation of hydrogen through electrolysis possesses several advantages such as high efficiency, low pollution and decentralized fueling methods. In this paper, we show through modeling and simulation that the efficiency of hydrogen production can be further increased by operating the solid oxide electrolysis cell (SOEC) at the optimum combination of operating conditions. Specifically, the analysis of a recuperative SOEC that utilizes the thermal energy from the exhaust gases has revealed that operating the electrolysis cell above the thermoneutral voltage increased the efficiency of hydrogen production. We also found that the exit temperature of the gas streams depended on the operating voltage and steam utilization simultaneously. The effects of various operating parameters such as voltage, steam utilization, area specific resistance (ASR), the size of the heat exchangers, and the number of cells were analyzed in the system.