Resource efficiency in steelmaking: energy and materials combined

Currently the metrics used to compare plants and to define how well these use resources take the form of energy intensities or yields. Both of these ignore the physical value of material by-products and focus separately on a single resource. A resource efficiency metric is proposed, measured in exergy, as a tool to more holistically compare the efficiency with which industry consumes energy and materials. This metric allows us to integrate four main options to improve resource efficiency, commonly viewed separately, including: the reduction of fuel and material inputs, and the recovery of energy and material by-products. Global worldsteel data for primary steelmaking is used to quantify the resource efficiency of processes and integrated sites. Globally, the primary production route has an average resource efficiency of 23%. This efficiency is double that of the global energy system, 11%, and is close to the most efficient conversion device, the aircraft engine, typically 25% efficient. It is estimated that improving the recovery of energy and material by-products in the steel industry globally, can push the resource efficiency to over 36%.