A suggested methodological framework to enhance comparability and reliability for life cycle assessment of CO2 adsorption in energy-intensive industries

Among the various CO2 capture technologies, adsorption capture appears to be an emerging and promising technology characterised by operational flexibility, low pollutant emissions, and low energy consumption. It is expected to be crucial in carbon capture and storage systems. Whilst Life Cycle Assessment (LCA) has emerged as the consensus methodology for evaluating the environmental impacts of this technology, methodological heterogeneity in LCA applications has limited the comparability and credibility of research findings. This study systematically reviews 31 LCA studies published between 2006 and 2025, examining methodological commonalities and differences across four aspects: goal and scope definition, inventory analysis, impact assessment and interpretation. Current LCA methodological standards and guidelines were used as benchmarks to analyse the challenges and opportunities in CO2 adsorption LCA methodology and to propose a methodological framework. The findings reveal that commonalities (e.g., functional unit) and differences (e.g., system boundary, life cycle stages and process stage alignments) exist among LCA methodologies. Moreover, compared to existing standards and guidelines, current methodological applications demonstrate notable gaps (e.g., the lack of data quality evaluation and the classification of significance levels). Consequently, we propose a hierarchical improvement framework comprising three levels based on required additional effort levels- minor, moderate, and major efforts. This framework aims to systematically enhance the comparability and reliability of LCA studies. This work contributes to establishing common LCA application protocols and provides methodological guidance for future environmental assessments of CO2 adsorption technologies.