Life cycle assessment of a newly designed thermochemical cycle and traditional steam methane reforming process for hydrogen production using coherent criteria

Methodological inconsistencies affect the accuracy and reliability of life-cycle assessment results of hydrogen production and mislead their interpretation. To avoid such consequences, the present work aims to employ newly developed and more coherent life cycle indicators to assess the environmental impacts of renewable hydrogen production. Two case studies are, in this regard, chosen to conduct a comparative assessment between the improved Sulfur–Iodine (S-I) thermochemical cycle and conventional steam methane reforming (SMR). A life cycle assessment (LCA) methodological framework is developed for the first time by coupling the LCA capabilities of the OpenLCA with the process simulation results from the Aspen Plus and thermal management results from the MATLAB. The environmental profile of both hydrogen production systems is assessed using a well-established set of life cycle performance indicators, based on the methodologies, namely: (1) carbon footprint via IPCC, (2) acidification footprint via CML, (3) non-renewable energy footprint via VDI, and (4) non-renewable exergy footprint via VDI. The results show that the predicted carbon footprint of the improved S–I cycle is 1422.71 g CO 2 eq./kg H 2 , whereas the conventional SMR hydrogen production process is associated with a significantly higher carbon footprint of 2642.72 g CO 2 eq./kg H 2 . Furthermore, the S–I cycle has an acidification footprint of 16.18 g SO 2 -eq/kg H 2 , a non-renewable energy footprint of 62.96 MJ eq/kg H 2 , and a non-renewable exergy footprint of 62.09 MJ eq/kg H 2 which is 63.89 %, 12.43 %, and 13.77 % less compared to the conventional SMR process. The environmental performance shows that the improved S–I configuration caused 46.16 % less carbon footprint than the conventional SMR process. • LCA of the novel improved sulfur-iodine thermochemical cycle is conducted. • Results are compared with the conventional steam methane reforming process. • A harmonized LCA approach integrates openLCA, Aspen Plus, and MATLAB. • The developed cycle exhibits a carbon footprint of 1422.71 g CO 2 eq./kg H 2 , 46.16 % lower than SMR. • Acidification footprint is reduced by 63.89 % compared to the steam methane reforming method.