Adaptive pathways for low-carbon steel: From waste utilization to policy-driven transitions

This study investigates the decarbonization of steel production by integrating advanced technologies and regional policy mechanisms, targeting the significant carbon footprint of the sector. We apply an integrated Water-Energy-Material-Hydrogen Nexus (WEMH) framework to analyze three steel production pathways—Blast Furnace–Basic Oxygen Furnace (BF–BOF), Midrex Direct Reduced Iron (DRI)–Electric Arc Furnace (EAF), and HYLIII DRI–EAF—under the constraints of water, energy, and carbon emissions. Results show that a 60 % reduction in CO 2 emissions can be achieved with the DRI process combined with syngas and carbon capture, utilization, and storage (CCUS), while HYLIII and retrofitted BF–BOF processes achieve emission reductions of 64 % and 74 %, respectively. Furthermore, a 50 % freshwater cap significantly reduces water withdrawals, with desalination systems supplying 29.8 10 6 m 3 /yr for Midrex, 16.4 10 6 m 3 /yr for HYLIII, and 1.6 10 6 m 3 /yr for BF–BOF. Under a $/tCO 2 carbon tax, the Midrex capacity in coastal regions increases from 111 000 tonnes to 3.78 million tonnes annually, while gas-fired power in arid areas, such as Kerman, drops by 85 %. Waste gasification displaces 31 % of the hydrogen produced via steam reforming, and 49 % of coke use in BF–BOF is replaced with waste-derived syngas, resulting in a 65 % reduction in system-wide CO 2 emissions. These findings highlight the need for tailored, region-specific strategies to achieve low-carbon steel production while ensuring economic and environmental sustainability.