Abstract
The iron and steel sector is central to national net-zero efforts but remains hard to abate(1,2). Existing decarbonization roadmaps fail to guide technology choices for individual plants, given their heterogeneity and economic constraints(3-5). Here, by integrating two global plant-level datasets and forecasted technology costs, we develop a model to identify the least-cost technology pathway for each plant worldwide in alignment with national carbon-neutrality targets. In the short term (pre-2030), energy efficiency improvements and scrap reuse are the cheapest decarbonization strategies, reducing cumulative global carbon dioxide (CO(2)) emissions by 7.8 Gt and 7.2 Gt at average costs of -US$8.5 tCO(2)(-1) and US$0.3 tCO(2)(-1), respectively. In the long term (after 2030), smelt reduction with carbon capture is expected to become technically mature and economically viable, achieving approximately 6.0 Gt of CO(2) reductions at costs of US$7-15 tCO(2)(-1) in Chinese plants and US$26-75 tCO(2)(-1) in plants across Japan, Korea and Europe. After 2040, green-hydrogen-based steelmaking is estimated to contribute an additional 0.3 Gt of CO(2) abatement in European plants at costs of US$27-44 tCO(2)(-1). This study tailors plant-specific least-cost technology pathways that reconcile stakeholders' economic interests with climate objectives, enabling actionable decarbonization strategies and supporting global net-zero targets.