Abstract
Steel production accounts for approximately 6% of global greenhouse gas (GHG) emissions, making the deep decarbonization of this sector a critical priority. As global expectations for transparent environmental reporting rise (e.g., the EU's Carbon Border Adjustment Mechanism, CBAM), there's a growing need for consistent and comparable environmental data in steel production. Environmental Product Declarations (EPDs) provide a standardized approach to communicate cradle-to-gate Life Cycle Assessment (LCA) results, while LCA itself offers a comprehensive framework to evaluate multiple impact categories and pinpoint potential environmental trade-offs among different steelmaking pathways.
This study establishes an LCA-based benchmark of the most used primary steelmaking pathways, including Blast Furnace–Basic Oxygen Furnace (BF–BOF), Direct Reduced Iron–Electric Arc Furnace (DRI–EAF), and coal-based rotary kiln pathways. We further evaluate decarbonized variants: BF–BOF with carbon capture and storage (CCS), DRI–EAF with CCS, biomass-enabled DRI–EAF with CCS (BECCS), and hydrogen-based DRI (H₂–DRI). To reflect Canadian production contexts, key LCI parameters such as transportation, distances, transportation modes, scrap shares, and energy mixes are user-adjustable within the LCA benchmarking tool. Where an inventory gap exists, mass and energy requirements are estimated using thermodynamic simulation informed by the FactSage database.
Results indicate that, for conventional routes, more than 70% of total GHG emissions and aggregated environmental impacts concentrate in the ironmaking stage across all routes. CCS applied to BF–BOF achieves substantial GHG reductions relative to the conventional baseline; however, shifting to DRI-based ironmaking enables even greater climate benefits. These gains must be weighed against resource constraints and system-level effects: BECCS requires sustained, large-scale biomass supply chains that may strain forestry systems, while H2-DRI in regions like Québec implies significant additional electricity demand. Meeting this demand represents a large attribution of the land use and associated ecological footprints of existing hydroelectric installations. By providing harmonized and transparent LCA results for current and emerging steelmaking routes, this benchmark supports industry and policymakers in identifying low-emission production options, informing EPD development, and evaluating decarbonization strategies.