<![CDATA[Steel decarbonization is a global priority due to its high energy use and emissions. In Thailand, this challenge is shaped by reliance on scrap-based EAF systems, where emissions depend on carbon-intensive electricity and limited scrap availability and quality. This study evaluates the environmental competitiveness and decarbonization potential of hydrogen-based direct reduced iron (H₂-DRI) integrated with electric arc furnace (EAF) steelmaking under Thailand-specific conditions. A cradle-to-gate life cycle assessment was conducted to compare 100% scrap-based EAF with four H₂-DRI-EAF scenarios (25%, 50%, 75%, and 100% DRI) using grey, blue, and green hydrogen. The ReCiPe 2016 method was applied to evaluate global warming and endpoint impacts on human health, ecosystem quality, and resource scarcity. Results showed that the baseline scrap-based EAF has the lowest environmental burden. Among hydrogen pathways, blue hydrogen achieves the greatest climate benefits, reaching 552 kg CO₂-eq/t, while grey hydrogen exhibits the highest impacts across all categories. Green hydrogen does not outperform the baseline under current conditions due to upstream burdens. Furthermore, endpoint contribution analysis revealed the overall emissions profile, highlighting trade-offs between climate change and other midpoint impact categories. Results suggest that Thailand should pursue a dual-pathway steel decarbonization strategy that combines optimized scrap-based EAF production with the gradual deployment of hydrogen-based DRI-EAF to address future constraints in scrap availability and quality. Compared with conventional natural gas-based DRI-EAF, blue and green hydrogen pathways achieved greenhouse gas reductions of 58.7% and 37.6%, respectively, highlighting their potential to support Thailand’s long-term climate and industrial development objectives.]]>
