Technoeconomic analysis of low-emission steelmaking using hydrogen thermal plasma

Hydrogen thermal plasma has been identified as a possible breakthrough pathway for low-CO2-emission steelmaking, but it remains unclear whether it can be economically competitive with other low-emission alternatives. This study develops a static mass and energy flow model of three plasma-based steelmaking processes, and investigates the performance required to be economically competitive with the more established hydrogen direct reduction – electric arc furnace (HDR-EAF) pathway. The technoeconomic analysis in this paper finds that in some scenarios, plasma processes are cheaper than HDR-EAF steelmaking when using medium-grade ore (59 wt% Fe), primarily due to lower capex and flux requirements. A novel two-stage plasma-BOF pathway achieves the lowest levelised cost of steel in most scenarios. However, when using high-grade ore (65 wt% Fe), HDR-EAF steelmaking achieves a levelised cost of 667 USD/tLS, which is cheaper than single-stage plasma steelmaking at 677 USD/tLS. This finding is sensitive to several assumptions, particularly the plasma smelter efficiency. A minimum plasma-smelter thermal efficiency of 82% is required for cost parity with HDR-EAF steelmaking for medium-grade ore. Partial prereduction of the ore to wüstite via direct reduction provides cost savings when plasma-smelter efficiency is low.