Life Cycle Assessment and Life Cycle Costing of unitized regenerative fuel cell: A systematic review

Unitized Regenerative Fuel Cell (URFC) is considered a promising green hydrogen technology for producing clean energy, but further research is needed to make it attractive for a wide range of sectors and applications. In particular, the environmental and economic implications related to the life cycle of this electrochemical device play a fundamental role in determining its attractiveness and potential for improvement, and Life Cycle Thinking (LCT) assessment methods are considered to be the most effective means to improve knowledge about these implications. In this context, the present article provides a systematic and bibliometric literature review analysis of Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) studies applied to URFCs using proton exchange membrane (PEM) devices. The aim is to evaluate the state-of-the-art of implementations of LCT methods to this electrochemical device in order to highlight good practices and critical issues, referred to both technical and methodological data. A reference sample of 44 scientific articles is extracted from the Web of Science (WoS), Scopus, and ScienceDirect databases and analysed using two computational tools: VOS viewer and Microsoft Excel. This group of publications helped establish the development over the last few decades of some key themes: LCC and LCA studies applied on PEM and URFC, also extending the search to its main components (such as fuel cell and electrolyser) and its original shape (i.e., regenerative fuel cell). The results of the analysis are presented quantitatively and qualitatively. Regarding the technical issues, there is significant variability in environmental and economic impacts, given by the selected system boundaries, the final users, and the fuel used by the systems. Regarding the methodological issues, no consensus emerges on how to model the LCT studies according to functional units, system boundaries, type of data selected, or model environmental externalities. The analysis also highlights the strong need for a higher level of transparency and harmonization of LCAs and LCCs applied on PEM technologies in order to improve the comparability of the results of these assessments.