Integrated assessment of resource-energy-environment nexus in China's iron and steel industry

MESSAGEix model are widely used for forecasting long-term energy consumption and emissions, as well as modelling the possible GHGs mitigations. However, because of the complexity of manufacturing sectors, the MESSAGEix model aggregate detailed technology options and thereby miss linkages across sub-sectors, which leads to energy saving potentials are often not very realistic and cannot be used to design specific policies. Here, we integrate Material/Energy/water Flow Analysis (MEWFA) and nexus approach into the MESSAGEix to estimate resource-energy-environment nexus in China's iron and steel industry. Results show that between 2010 and 2050 energy efficiency measures and route shifting of China's steel industry will decrease raw material input by 14%, energy use by 7%, water consumption by 8%, CO₂ emissions by 7%, NOx emissions by 9%, and SO₂ emissions by 14%, respectively. However, water withdrawal and PM_2.5 emissions will increase by 14% and 20%, respectively. The main reason is that water withdrawal and PM_2.5 emissions in the process of BF-BOF are over 4 times lower than the process scrap-EAF. Therefore, policy makers should consider nexus effects when design integrated policy to achieve multiple targets. Finally, future directions on enhancing the representation of manufacturing sectors in IAMs are given.