Using life cycle assessment to evaluate the environmental impacts of four hydrogen production pathways applied to the transport sector

The transition to a zero-emission transport sector is essential for meeting climate targets, with hydrogen emerging as a promising alternative fuel. This study applies a cradle-to-gate Life Cycle Assessment (LCA) to evaluate the environmental impacts of four hydrogen production pathways (Green, Blue, Grey, and Turquoise) across production, compression, transport (pipeline vs. truck), and refuelling. The assessment follows ISO 14040/14044 standards and considers Global Warming Potential (GWP), Acidification (AP), Eutrophication (EP), and Marine Aquatic Ecotoxicity (MAETP). Results show that Green hydrogen has the lowest GWP (0.773 kg CO 2 -eq/kg H 2 ), while Grey hydrogen has the highest (11.6 kg CO 2 -eq/kg H 2 ). Blue hydrogen reduces emissions by 56% via CCS, whereas Turquoise hydrogen shows moderate GWP but the highest ecotoxicity. Pipeline delivery consistently outperforms truck transport. Overall, Green hydrogen is identified as the most sustainable pathway, highlighting the importance of renewable integration and infrastructure development.