Assessment of midterm CO₂ emissions reduction potential in the iron and steel industry: a case of Japan

An up-to-date techno-economic assessment was conducted on CO₂ emissions reduction potential in the Japanese iron and steel industry for 2030. The following mitigation measures were investigated: (i) maximized installation of best available technologies (BAT scenario), (ii) increased use of coke substitutes in blast furnaces, and (iii) increased use of obsolete steel scrap. For measure (iii), this study assessed the obsolete scrap use in the integrated steelmaking (BF-BOF) route, rather than increasing steel production from the electric arc furnace (EAF) route. CO₂ capture and storage (CCS) was not considered due to large deployment uncertainty. The results showed that 20 Mt–CO₂ of emissions reductions, equivalent to 12% of the industry's total emissions in 2010, can be achieved in 2030 compared with a frozen technology scenario. More than 9 Mt–CO₂ reduction was attributable to the enhanced use of obsolete scrap in the BF-BOF route. Consequently, the industry's emissions reduce by about 7 Mt–CO₂ or 4% below 2010 levels. Almost all domestically recovered obsolete scrap can be fully consumed solely by increasing the scrap use in basic oxygen furnaces (BOF). Moreover, the increase in average copper concentration in the BF-BOF steel due to the increased obsolete scrap use was found unlikely to limit the production of high-quality steel products. In comparison with a scenario that only considered measure (i) and assuming a 15% real interest rate, CO₂ mitigation cost curves for 2030 showed that the CO₂ mitigation costs were below US$₂₀₁₀ 20/t-CO₂ for measure (ii) and around US$₂₀₁₀ 110/t-CO₂ for measure (iii). Compared to the marginal abatement costs calculated for 2030 to reduce Japan's GHG emissions by 20%–25% from 1990 levels (about US$₂₀₁₀ 67–640/t-CO₂) reported in the literature, all three measures may become economically viable. The increased use of obsolete scrap in the BF-BOF route can become an interesting option for Japanese steelmakers to stimulate the steel scrap market and achieve economical global CO₂ emissions reductions while maintaining international competitiveness in the midterm future.