Calcium looping for carbon capture in power plants and hard-to-abate industries: Critical review of technical, economic, environmental performance and scalability pathways

Calcium looping (CaL) is a promising high-temperature CO₂-capture technology for power generation and hard-to-abate industries because it combines inexpensive Ca-based sorbents with opportunities for process, material and heat integration. However, substantial uncertainty remains regarding whether favorable laboratory, pilot and modeling results can be translated into reliable commercial deployment. This review applies a structured literature-search and evidence-classification procedure to 245 references, including 174 core CaL studies, and critically integrates technical performance, techno-economic assessment (TEA), life-cycle assessment (LCA), evidence maturity and scale-up constraints across power generation, cement, lime and steel production. Pilot facilities have demonstrated CO₂ capture above 90%, but validation remains concentrated at laboratory to low-MW_th scale, whereas most whole-plant efficiency and cost advantages remain simulation-derived. Optimized configurations report energy penalties of approximately 5–10%, although these values are highly dependent on fuel properties, reference systems, sorbent management and heat-integration assumptions. Deterministic TEAs of conventional coal-based configurations frequently report CO₂ avoidance costs of 20–60 $/t, but broader economic performance is sensitive to plant utilization, capital and financing assumptions, sorbent degradation and downstream CO₂ handling. LCAs generally indicate GWP reductions of approximately 60–80% relative to their respective reference systems, although inconsistent boundaries, background databases, calciner heat sources and allocation methods limit direct comparability. Power and cement currently exhibit the strongest integrated evidence, while dedicated lime validation and steel-sector deployment remain less mature. An operational AHP–TOPSIS framework is therefore proposed to translate technical, economic, environmental and deployment constraints into sector-specific decision criteria. CaL should not be regarded as universally superior to alternative capture technologies; its credible deployment depends on long-duration validation, low-carbon heat, material circularity, shared CO₂ infrastructure and stable, sector-appropriate policy support.