Multi-dimensional assessment of decarbonization technologies and pathways in China's iron and steel industry: An energy-process chain perspective

China's iron and steel industry, significant for national economic development, is notable for high energy consumption and carbon emissions. To balance industry growth with carbon neutrality goals, it is crucial to analyze emissions throughout production processes. This study begins with an industry overview, followed by an analysis of the ‘Energy-Material-Carbon Nexus’ (EMC Nexus) in steel production. Referencing the National Key Low-Carbon Technology Promotion Catalogue and considering hydrogen replacement and process substitution technologies, 52 potential energy-saving and emission-reduction technologies are identified. By integrating these technologies with production steps, a comprehensive carbon reduction model is established under the framework of the energy-process chain, providing standardized methods for calculating abatement potential and abatement costs. Subsequently, employing the Analytic Hierarchy Process (AHP), the feasibility of each technology is ranked based on five dimensions: policy support, technological complexity, abatement cost, abatement potential and payback period. Finally, based on the Marginal Abatement Cost Function, this study proposes a method for fitting the cost curve of carbon abatement. To analyze the medium and long-term trends in carbon reduction potential and comprehensive ranking of energy-saving and emission-reduction technologies in China's steel production, empirical analysis is conducted for four target years: 2030, 2040, 2050, and 2060. The results demonstrate significant abatement potential in China's iron and steel industry. Taking the target year 2030 as an example, the average unit abatement cost is 287.29 ¥/ton, with an annual abatement potential of 3.755 million ton, accounting for 18.1 % of the industry's total emissions. Using the proposed multi-dimensional approach for comprehensive evaluation of energy-saving and emission-reduction technologies, comparative analysis of ranking results across different target years confirms the substantial carbon abatement potential of Scrap-based electric arc furnace steelmaking technology and two hydrogen-based technologies in the medium and long-term. Furthermore, the fitted relationship between total abatement costs and abatement volumes under different target years for China's iron and steel industry provides mathematical tools for macro policy-making and industry-level carbon simulation. While the proposed research methodology demonstrates general applicability, some conclusions are dependent on scenario parameter settings and questionnaire implementation in the empirical analysis. This study aims to provide valuable insights for the design and implementation of decarbonization processes in China's iron and steel industry.