Technological pathways for cost-effective steel decarbonization

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 (CO₂) emissions by 7.8 Gt and 7.2 Gt at average costs of -US$8.5 tCO₂^-1 and US$0.3 tCO₂^-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 CO₂ reductions at costs of US$7-15 tCO₂^-1 in Chinese plants and US$26-75 tCO₂^-1 in plants across Japan, Korea and Europe. After 2040, green-hydrogen-based steelmaking is estimated to contribute an additional 0.3 Gt of CO₂ abatement in European plants at costs of US$27-44 tCO₂^-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.