An integrated assessment model for cost-effective long-term decarbonization pathways in China's iron and steel industry

Decarbonization in the iron and steel industry is critical for climate action and sustainable development. Existing research on cost-effective decarbonization technologies is limited, often overlooking optimal multi-technology strategies that balance decarbonization and economic feasibility. We developed an integrated assessment model to optimize long-term decarbonization strategies by evaluating low-carbon technologies based on decarbonization costs, penetration rates, payback times, service life, and benefit-cost ratio. The model aims to identify optimal dynamic development pathways for a series of decarbonization technologies up to 2035, minimizing both costs and carbon emissions through scenarios prioritizing emissions or costs. Under optimal pathways, the aggregate technology decarbonization potential and dynamic trends in industry CO2 emission intensity and costs were analyzed. We examined the impacts of changes in key input parameters, leading to variable multi-technology dynamic development pathways. Our findings indicate that decarbonization costs for BF-BOF (Blast furnace-basic oxygen furnace) and EAF (Electric arc furnace) technologies range from −-0.5 to 0.4 yuan/kgCO2 and -0.3 to −0.02 yuan/kgCO2, demonstrating high economic viability under higher carbon prices. Optimal development pathways suggest significant annual changes within BF-BOF and EAF routes, classifying technologies by cumulative decarbonization potential into advanced, moderate, and conservative categories. Future CO2 emission intensities decrease more significantly in the EAF route, indicating a higher decarbonization capacity, while total costs increased annually due to rising emission costs and declining energy costs. The optimal multi-technology dynamic development pathways are influenced by production routes, carbon prices, and energy supply modes, with cleaner energy reducing the need for aggressive decarbonization technology adoption.