Integrated Product- and Entity-Level Carbon Accounting Case Study: Steel Production Using Blast Furnace–Basic Oxygen Furnace (April 2026) applies the EFI Foundation (EFIF) ledger-based carbon accounting framework to an illustrative integrated steel plant in East Chicago, Indiana using the blast furnace–basic oxygen furnace (BF-BOF) technology. The ledger-based framework was first described in the October 2025 EFIF report.
The system integrates engineering mass and energy balances with financial accounting principles, tracking carbon stocks and flows—including carbon dioxide (CO2), methane, carbon monoxide, and volatile organic compounds—across supply chain entities from upstream suppliers to downstream customers. Over a one-month period, the facility produces 416,000 tons of steel using iron ore, metallurgical coal, limestone, scrap steel, natural gas, and electricity, with carbon capture and storage (CCS) reducing the pathway’s emissions. The resulting cradle-to-gate product carbon intensity is 1.1 tons of CO2 per ton of steel.
The case study shows how emissions, physical carbon content, inventories, byproducts, and transportation can be recorded in a dual-sided carbon ledger that balances stocks and flows. In the BF-BOF pathway, the system tracks upstream supplier emissions, direct process emissions from coke combustion and basic oxygen furnace operations, and captured emissions.
The case study demonstrates that BF-BOF steel remains far more carbon intensive than alternative steel production pathways such as hydrogen direct reduced iron-electric arc furnace (H2-DRI-EAF), even with CCS. A detailed demonstration of the H2-DRI-EAF pathway can be found in a companion case study. Both case studies show how a transparent, auditable accounting system can support product-level emissions reporting, customer disclosure, and policy or procurement decisions by providing a consistent basis for comparing steel products across supply chains.
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