Harmonized comparison of virgin steel production using biomass with carbon capture and storage for negative emissions

A harmonized method was developed to assess CO₂ mitigation performance and avoidance costs for different steel production routes, including blast furnace with blast oxygen furnace (BOF), direct reduced iron (DRI) production with electric arc furnace (EAF), and Hisarna with BOF. Mass and energy balances were used to evaluate each route's cradle-to-gate CO_2eq emissions. Results indicate that using either CO₂ capture and storage (CCS) or biomass can reduce, but not eliminate, CO_2eq emissions in the iron and steel sector. However, the combination of CCS and biomass (BECCS) can result in CO₂-neutral or even CO₂-negative steelmaking. The results show that implementation of BECCS is possible at an avoidance cost < 100 €/t CO_2eq. BECCS combined with carbon neutral electricity has a CO₂ mitigation potential of 107–139% with CO₂ avoidance costs of 59–157 €/t CO_2eq. Reducing biomass upstream emissions could further improve these results. The Biomass-DRI-EAF-CCS route has the highest CO₂ mitigation potential (146%), while the Biomass-Hisarna-BOF-CCS route has the lowest CO₂ avoidance cost (54 €/t CO_2eq). This study indicates that the developed harmonized methodology can also be applied in other industrial sectors to screen different portfolios of mitigation options.