Energy-saving and emission-reduction technology selection and CO2 emission reduction potential of China’s iron and steel industry under energy substitution policy

The carbonisation of energy structures is a principal reason for the high carbon levels of carbon dioxide (CO2) emissions in the steel industry. The implementation of an energy substitution policy in the Chinese steel industry has important practical significance for this industry in terms of reducing CO2 emissions. Based on this, this paper divides 20 types of energy-saving and emission-reduction (ESER) technologies into 4 categories: coal-saving technology, electricity-saving technology, comprehensive energy-saving technology, and linkage technology according to the energy-saving effect of different technology on energy varieties. Considering the energy substitution constraints on energy structures within the steel industry, we construct a bottom-up optimisation model based on a scenario analysis to analyse the emission reductions under 3 different scenarios: the baseline scenario (BAU), policy scenario (PS), and strengthened policy scenario (SPS). Results show that the emission reduction of coal-saving technology and comprehensive energy-saving technology in 2030 is 102 million tons CO2 (MtCO2) and 129 MtCO2, respectively, in the PS, and 116 MtCO2 and 130 MtCO2, respectively, in the SPS. Compared with these types of technology, electricity-saving technology is maintained at the level of the BAU. Linkage technology is developed in the latter period of the SPS. The emission reduction of linkage technology in the SPS in 2030 will be 4.1 MtCO2. During the period of 2015–2020, priority should be given to the development of thin slab continuous casting technology in comprehensive energy-saving technology and the development of blast furnace thick phase high efficiency coal injection technology in coal-saving technology. During the period 2020–2030, priority should be given to the development of thick layer sintering technology, hot delivery & hot charging technology of continuous casting slab, online treatment technology in comprehensive energy-saving technology and low temperature rolling technology, converter ‘negative energy steelmaking’ technology, and double preheating technology for hot stove of blast furnace in coal-saving technology.