Decarbonizing hard-to-abate sectors: CO₂ emission characteristics and mitigation pathways for steel, aluminum, and cement in China

Abstract

The steel, aluminum, and cement industries are among the most energy- and carbon-intensive sectors globally. Systematically identifying their carbon emission characteristics and key mitigation pathways is critical for achieving industrial low-carbon transitions. However, existing studies lack comprehensive comparative analyses of product-level CO₂ emissions and their driving factors across different technological routes, making decarbonization pathways for these high-emission industries unclear. This study adopts a material flow analysis approach to evaluate the unit product CO₂ emissions of six typical manufacturing processes in China's steel, aluminum, and cement industries. Results show that CO₂ emissions for crude steel production under the Blast furnace-basic oxygen furnace, hydrogen-based direct reduction iron, and Scrap-based electric arc furnace routes are 1891.92, 1198.66, and 759.24 kgCO₂/t-s respectively, while those for primary and secondary aluminum are 16,648.21 and 612.04 kgCO₂/t-al, respectively. Cement production emits 623.5 kgCO₂/t-c. In addition, scenario analysis indicates that by 2060, compared to 2023 levels, combined mitigation strategies could reduce China's emissions by 70%–90%. The steel industry should prioritize the development of hydrogen-based metallurgy and electric arc furnace technologies, the aluminum industry should accelerate the use of green electricity and increase the share of secondary aluminum, and the cement industry should strengthen the deployment of CCUS for achieving carbon neutrality.