Comparative optimization study of three novel integrated hydrogen production systems with SOEC, PEM, and alkaline electrolyzer

The present research conducts a comparative analysis and techno-economic optimization of three novel integrated energy systems for producing hydrogen, power, and desalinated water. These systems consist of heliostat field collectors, photovoltaic panels, a Rankine cycle, an organic Rankine cycle (ORC), and multi-effects water desalination systems. The main difference between the three proposed systems is the electrolyzer type. Three electrolyzer types are utilized: solid oxide electrolyzer cell (SOEC), polymer electrolyte membrane electrolyzer (PEM), and alkaline electrolyzer. This research aims to compare these three types of electrolyzers in an integrated system to analyze their performance from both exergy and economic viewpoint at their optimum conditions. Parametric studies on system exergy efficiency and hydrogen production rate were also conducted. The results demonstrate that in the exergy-economic optimum conditions, the exergy efficiency of the combined solid oxide system, polymer exchange membrane system, and Alkaline system are 13.15%, 13.04%, and 12.41%, respectively. As SOEC works at high temperatures, both thermal and electrical energy cooperate to produce hydrogen. Therefore, the maximum hydrogen production rate and system exergy efficiency happen in the integrated SOEC system. Although the SOEC system has the most significant cost rate of 0.9372 $/s, the most expensive hydrogen cost belongs to the PEM system with a charge of 3.54 $/kg, and the cheapest one is produced in the alkaline system at 2.94 $/kg.