Sustainability assessment of advanced calcium looping solutions for the decarbonization of the iron and steel industry

Achieving the 1.5°C climate target by 2050 requires urgent action in the steelmaking sector, as it contributes by about 7% to global CO 2 emissions. With Electric Arc Furnace (EAF) routes representing 30% of global production, their decarbonization is critical to sector-wide emission reductions. The current study evaluates the environmental implications of an EAF equipped with a Calcium Looping (CaL) based carbon capture unit via Life Cycle Assessment (LCA) methodology. The environmental analysis follows a cradle-to-gate approach and it is conducted using the ReCiPe 2016 assessment method. Four distinct CaL configurations featuring variations such as intermediate solid storage and/or calcium hydroxide, Ca(OH) 2 , injection were investigated, each assessed under two alternative CO 2 transportation scenarios: T1 – onshore pipeline followed by offshore shipping, and T2 – onshore truck transportation followed by offshore shipping. The findings suggest more than 63% Global Warming Potential (GWP) reduction in the advanced CaL configurations as against standard strategies, primarily due to Ca(OH) 2 injection (i.e., enhanced CO 2 capture efficiency) and CO 2 purification unit (CPU) vent gas recirculation. However, these improvements are offset by higher impacts in Fossil Depletion Potential (FDP), Mineral Depletion Potential (MDP), Photochemical Oxidant Formation Potential ecosystem (POFP ecosystem ), Photochemical Oxidant Formation Potential human health (POFP human-health ), Stratospheric Ozone Depletion Potential (ODP), and Terrestrial Ecotoxicity Potential (TETP). Of the two CO 2 transportation pathways, T1 and T2 show similar values in five indicators (i.e., Freshwater Ecotoxicity Potential – FETP, Freshwater Eutrophication Potential – FEP, Human Toxicity Potential cancer – HTP cancer , MDP, and HTP non-cancer ), yet T1 outperforms T2 in terms of GWP, FDP, POFP ecosystem , POFP human-health , ODP, and TETP. Of all scenarios, the advanced CaL configuration with two intermediate storage tanks coupled with T1 exhibits the best overall environmental performance. A detailed analysis reveals that the CO 2 transportation contributes around 16.8 kg CO2 eq. /t CO2 captured , emphasizing the importance of developing alternative transport strategies to reduce associated emissions.