In this study, we present the thermodynamic feasibility analysis of a two-step hydrogen chloride cycle for sustainable hydrogen production. Exergy approach in addition to conventional energy approach is utilized to study the performance of the cycle. Here, a solid oxide membrane for the gas phase electrolysis of hydrogen chloride is employed and the temperature change between the cycle steps is eliminated for better thermal management. Moreover, a parametric study is conducted to observe the cycle variation with certain parameters such as operating temperature, current density, and hydrogen production rate. The calculated results show that with the use of the current cycle, one can produce 1 kg/s of hydrogen with the consumption of 335.8 MW electricity and 29.2 MW of thermal energy. Additionally, two different definitions of energy and exergy efficiencies are introduced to investigate the difference between actual and ideal (theoretical) cycle performances. The proposed cycle can be effectively used to produce hydrogen using concentrated solar and nuclear waste heat at high temperatures. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.