Biomass as a Source of Renewable Carbon for Iron and Steelmaking

Fossil fuel-based carbon is widely used in iron and steelmaking, and transitioning to renewable carbon sourced from biomass is viewed as a promising strategy to minimize the greenhouse gas emissions associated with steel production. This study employs life cycle assessment methodology to quantify the greenhouse gas footprint from charcoal production derived from biomass and explores its potential to reduce emissions in various steelmaking routes, including integrated, mini-mill/EAF, and direct smelting processes. The findings suggest that integrating biomass charcoal can significantly lower the carbon footprint, achieving reductions of 0.69–1.21 t CO2e/t steel (31–57%) without by-product credits and up to 1.61 t CO2e/t steel (74%) when such credits are included for the integrated method. For the mini-mill/EAF and direct smelting paths, reductions range from 0.028–1.70 t CO2e/t steel, alongside major variations in the effectiveness of by-product credits based on the pyrolysis process and feedstock composition. The study also evaluates potential biomass plantation areas for sustainable charcoal production, highlighting the feasibility of using charcoal in place of coal or coke in global steelmaking. Nevertheless, issues such as transportation costs pose challenges to the widespread adoption of charcoal in this sector.