Assessing the Hydrogen Supply Chain from an Eco-Design Perspective: Challenges and Opportunities for Sustainability

Hydrogen (H2) is widely regarded as a key energy vector for the transition to a low-carbon energy economy, yet its production, storage, and distribution remain associated with significant environmental burdens. This review analyses the entire low-emission H2 value chain from an eco-design perspective, synthesising recent life cycle assessment (LCA) literature on water-splitting technologies (electrolysis, thermochemical cycles, and photocatalysis), biomass-based thermochemical and biological routes, and the emerging exploitation of natural (geological) hydrogen. Environmental performance is benchmarked against conventional steam methane reforming and coal gasification across multiple indicators, including global warming potential (GWP), terrestrial acidification, water scarcity, mineral resource scarcity, and human toxicity. The results demonstrate that no single pathway is universally sustainable. Electrolysis remains strongly dependent on the electricity grid mix, while biomass gasification coupled with carbon capture and storage (CCS) achieves deep carbon mitigation but exacerbates acidification concerns. Furthermore, photocatalysis and biological routes show theoretically low carbon footprints but remain severely constrained by low technology readiness levels (TRLs). Downstream, physical compression showed lower life cycle burdens than chemical carriers, and pipeline networks outperformed other transportation modes, in the studies reviewed; both findings are conditional on the distance, scale, pressure and utilisation assumptions adopted. Finally, the integrated economic overview reveals that environmental hotspots correlate directly to financial penalties, ultimately dictating the levelised cost of hydrogen (LCOH). This review consolidates critical technological gaps, highlights the necessity for harmonised LCA boundaries, multi-indicator reporting, and primary industrial data, and proposes strategic research directions to enable a truly sustainable H2 economy where eco-design choices are matched to localised energy, water, and material realities.