Life-cycle cost (LCC) applied to hydrogen technologies: a review

Purpose: The aim of this research is to carry out a literature review on the use of life-cycle cost (LCC) approaches for hydrogen technologies, by analysing its evolution over a decade (2012-2021). Methods: The SCOPUS database has been used to select relevant literature on the subject. After adoption of inclusion/exclusion criteria, a total of 67 papers were selected for our review. Then, we analysed these studies in terms of hydrogen technologies (fuel cells, electrolysers, hydrogen storage approach, etc.) covered by the LCC approaches. In addition, we also performed an analysis of the LCC features -- type of LCC (conventional, environmental, social), integration with LCA/S-LCA, guidelines followed, system boundaries (cradle-to-farm gate, cradle-to-consumer, cradle-to-grave, cradle-to-cradle), functional units, financial tools (NPV, BEP, etc.), type of costs included, and life span -- to provide a comprehensive view of LCC studies applied to hydrogen technologies. We also discussed and interpreted the most significant findings. Results and discussion: Our main results can be summarised as follows: (i) the number of LCC studies for application to hydrogen technologies has increased in the decade 2012-2021; (ii) China is the leading country for number of publications on the subject (15 papers), even if the most prolific author and institution are Iranians; (iii) a large number of studies performed LCC analysis including fuel cells and/or electrolysers based on proton exchange membranes; (iv) the most widely used LCC approach is a cradle-to-consumer (37 papers); (vi) almost all the studies on LCC of hydrogen technologies included initial, operation and maintenance costs; while other costs -- replacement, external, end-of-life -- are included in a limited number of papers; (vii) the net present value (NPV) is the most used financial tool. Conclusions: LCC analysis for application to hydrogen technologies has gained interest in recent years. However, the number of studies that explicitly follow LCC or LCA guidelines is very limited (only 7). The life-cycle cost analyses performed are quite incomplete in terms of costs included in the life-cycle stages. Besides, there is a lack of information and uniformity in the use of functional units and financial tools.