The hydrogen life cycle assessment methodology: an overlooked puzzle piece in harmonizing hydrogen certification and trade

The hydrogen certification market faces intricate challenges that are intertwined and interdependent. This research paper employs the metaphor of fitting puzzle pieces together to delve into the complexities of the market. It highlights the central puzzle piece that often goes unnoticed: the life cycle assessment (LCA) methodology. The lack of compatibility in LCA methodologies across certifications creates significant hurdles in achieving harmonization of crucial aspects such as governance, hydrogen categorization, emissions threshold determination, segmented certification due to various hydrogen end-uses, and chain-of-custody tracking systems that catches the interest of research so far. To address this oversight, the paper adopts a structured approach to accomplish its objectives. Firstly, it thoroughly investigates the existing life cycle methodologies employed in global hydrogen schemes, treating them as distinct puzzle pieces. This analysis delves into key components of these methodologies, including eligible sources and pathways, functional unit determination, system boundary definition, cut-off rules, allocation choices, and impact assessment. By examining the differences and variations in these methodologies, the paper elucidates their intricate interplay with policymaking and segmented international goals. Moreover, the research tackles the challenges arising from LCA methodology misalignment in the hydrogen market, drawing parallels with the difficulty of fitting mismatched puzzle pieces together. It explores potential strategies to overcome these challenges by drawing insights from existing certification models in other sectors, such as advocating for internationally recognized standards, designing mutual recognition agreements, creating product category rules and comparability factors, and promoting convergence through market demand. Graphical abstract