Comparative life cycle assessment of decarbonization pathways for cement production in Nepal

• First LCA study on cement decarbonization pathways tailored to Nepal. • Post-combustion carbon capture cut CO 2 by 52% but increased other impacts. • Use of supplementary cementitious materials reduced GWP by up to 40%. • Hydrogen fuel use raised environmental burden due to high power demand. • AHP-based MCDA ranked SCMs pathway as the most sustainable option. Cement production is a major source of greenhouse gas emissions. In Nepal, rapid post-earthquake reconstruction and infrastructure development have significantly increased cement demand. The booming cement sector presents a significant challenge to the country’s net zero pledge by 2045. This study therefore presents the first life cycle assessment (LCA) of cement manufacturing in Nepal − an important step towards understanding the environmental impact of this critical industry. The environmental profile of cement production was assessed through a cradle-to-gate LCA using SimaPro software based on primary data collected from a representative plant. Several production pathways were evaluated including conventional coal-based system, system integrating post combustion carbon capture (PCCC), alternative fuel use, and clinker substitution with supplementary cementitious materials (SCMs). Pyro-processing was identified as the primary emission hotspot, contributing over 91.0 % and 88.0 % of the total global warming potential (GWP) ∼ 880 kg CO 2 eq./ton for ordinary Portland cement (OPC) and ∼ 771 kg CO 2 eq./ton for Portland pozzolana cement (PPC), respectively. PCCC systems achieved up to 52.0 % GWP reduction compared to conventional OPC, albeit with increased resource demands. Sensitivity analysis showed 5 % electricity efficiency improvements had a greater impact on GWP (up to 3.66 %) than coal reductions (up to 0.500 %), particularly in PCCC integrated systems. Uncertainty analysis revealed higher variability in electricity-intensive systems, while coal-based systems were more stable. A multi criteria decision analysis (MCDA) using analytic hierarchy process across 18 environmental indicators identified SCMs based pathway as the most sustainable option (aggregated score: 0.215). These findings provide actionable insights for steering Nepal’s cement industry towards a low carbon future.