Techno-economic assessment of green hydrogen production via two-step thermochemical water splitting using microwave

This study evaluates a two-step thermochemical water-splitting method for green hydrogen production and considers the economic feasibility of technically available designs under harsh hydrogen production conditions. As layouts of hydrogen production, two thermochemical water-splitting systems are evaluated in this study. One system is the process via high temperature from solar concentration power systems. The other system uses microwaves for thermochemical water splitting under low temperatures from advanced nuclear power plants. As part of the hydrogen production system, possible solid-solid and fluid-fluid heat recuperators of printed circuit heat exchanger (PCHE) are proposed and evaluated through the effectiveness-number of transfer units (epsilon-NTU) method and logarithmic mean temperature difference (LMTD) method. The required heat transfer area and volume are calculated according to the operating conditions and considered in the economic assessment of the hydrogen production system. Optimum geometries of the PCHE are proposed considering the cost analysis. The Levelized cost of hydrogen (LCOH) and system efficiency are calculated for the conventional system with solar power and system-using microwave with HTGR. The importance of heat recuperation systems is confirmed in that they account for approximately 10-20% of the cost for both system layouts. To evaluate the technology development level to achieve the ultimate target, LCOH according to various cost factors is evaluated and further research areas essential for commercialization are represented.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.