Co-production of steel and chemicals to mitigate hard-to-abate carbon emissions

Hard-to-abate sectors emitted ~30% of global CO2 emissions in 2018. As the world’s largest producer of chemicals and steel, China’s mitigation efforts in these sectors are crucial. Here we examine the greenhouse gas mitigation and costs of co-producing steel and chemicals in China by extracting H2 and CO from steelmaking off-gas for chemical production and using a customized optimization model with a life-cycle assessment. Without carbon pricing, co-production reduces greenhouse gas emissions by 36 MtCO2eq yr−1 (−7%) and costs by 1.5 billion CNY per year (−1%) relative to independent production. A carbon price of 350 CNY per tCO2 enhances emissions and cost reductions to 113 MtCO2eq yr−1 (−22%) and 25.5 billion CNY per year (−10%), respectively. Furthermore, 60% of total emissions and cost reductions can be achieved via 24% of connections, ~50% of which are in Hebei, Henan, Shanxi and Shandong provinces. This study demonstrates the cost-effectiveness of using co-production to mitigate these hard-to-abate emissions and the importance of targeting critical connections to obtain the majority of reductions. Achieving a net-zero future requires that hard-to-abate sectors be addressed. Co-production offers an opportunity to mitigate chemical and steel sector emissions by extracting H2 and CO from steelmaking off-gas and using them for chemical syntheses. The authors examine carbon mitigation and costs of co-producing chemicals and steel in China.