A bottom-up assessment of recent (2016–20) energy use by the global iron and steel industry constrained to match a top-down (International Energy Agency) assessment

This paper presents the first estimates, at the global scale, of energy use by energy type associated with individual steps in the production of fabricated steel products. Estimates are averaged over the period 2016–20, based on a synthesis of literature regarding energy use for (i) preparation of iron ore; (ii) production of iron in a blast furnace (BF) and as direct reduced iron; (iii) production of refined steel in the basic oxygen furnace or electric arc furnace; (iv) steel casting, hot and cold rolling, and coating; (v) fabrication of intermediate steel products; and (vi) processing of scrap. The International Energy Agency provides separate global energy use for coking, transformation energy use by BF, and by the remainder of the iron and steel industry (rISI) including the remaining BF energy use. With re-allocation of the BF portion of rISI back to BF, and a 9% increase in literature-based estimates of energy intensity across all production steps except coking, bottom-up and IEA estimates of total energy use agree. The resulting mean cumulative energy intensity of fabricated steel products is 24.1 GJ/t. The energy content of the lost iron equals about 10% of the total energy used in producing finished steel products.