Cost and life cycle analysis for deep CO2 emissions reduction of steelmaking: Blast furnace-basic oxygen furnace and electric arc furnace technologies

Abstract

Iron and steel manufacturing is the largest contributor to CO2 emissions among heavy industries worldwide. This is mostly due to the use of coal in blast furnace-basic oxygen furnace (BF-BOF) process for virgin (primary) steel production. The electricity generation mix used in the electric arc furnace (EAF) process to recycle scrap steel also contributes to the CO2 emission associated with secondary steel production. To decarbonize iron and steel sector, we investigated decarbonization options for BF-BOF and EAF processes, including energy efficiency, carbon capture and storage, and the use of clean energy sources, in various BF-BOF and EAF process configurations. For each decarbonization approach, we evaluated the CO2 reduction potential via life cycle analysis (LCA) and estimated the associated cost through techno-economic analysis (TEA). A typical U.S. BF-BOF for virgin steel production has a cradle-to-gate (CTG) CO2 emissions of 1,990 kg/MT steel with a levelized cost of steel (LCOS) of $439/MT steel, while a typical U.S. EAF process for secondary steel production in the United States has a CTG CO2 emissions of 270 kg/MT steel with a LCOS of $365/MT steel. Combining renewable energy sources and carbon capture, BF-BOF CTG CO2 emissions can be reduced to 16 kg/MT steel, and EAF configurations can achieve similar deep reductions to reach 25 kg/MT steel. The corresponding LCOS with these decarbonization levels is estimated to increase to $542/MT steel and $348/MT steel, respectively. The estimated CO2 avoidance costs vary from -$90/MT CO2 to $646/MT CO2, depending on the various decarbonization technologies and energy prices.