Heterogeneous operations and opportunities to reduce CO ₂ emissions in global blast furnace ironmaking

Abstract The blast furnace (BF) process accounts for over 90% of global iron ore-based steel production and remains a major contributor to CO 2 emissions. This study investigates the variability in operations across the global BF fleet and its impact on CO 2 emissions. Using plant-level data from 2011 to 2021, we find that variation in the composition of inputs results in emissions ranging from 1.20 to 2.08 tons of CO 2 per ton of hot metal (tCO 2 tHM −1 ) globally, driven by differences in fuel and reductant consumption. Our estimates suggest global emissions could have been lower by 2.8%—and up to 9.6%—if each furnace operated at its historical or national minimum CO 2 emissions intensity. We use furnace-level data to find even greater variation within and across individual furnaces at the national level, estimating potential for CO 2 emissions reductions of 5.7%–15.5% in the United States. These findings suggest substantial latitude to incentivize plants to reduce CO 2 emissions without new capital investment, by up to an estimated 1.35 billion tons of CO 2 cumulatively across the global BF fleet from 2011–2021. It further underscores the limitations of relying on ‘best available technology’ or country-specific emissions factors in policy and planning efforts.