Steel — Structural / Sheet Metal
Materials High Confidence
Carbon Cost Index Score
2 kgCO₂e / per kg
Per kg
2 kgCO₂e / kg
Methodology v1.0 · Last reviewed 2026-04-08
Scope Breakdown
| Scope | kgCO₂e | % of Total | Distribution |
|---|---|---|---|
| Scope 1 | 1.5 | 75% | |
| Scope 2 | 0.3 | 15% | |
| Scope 3 | 0.2 | 10% | |
| Total | 2 | 100% |
Emission Hotspots
| Emission Hotspot | Scope | Est. % of Total |
|---|---|---|
| Blast furnace iron-making (coke reduction of iron ore) | S1 | 55% |
| Basic oxygen furnace steelmaking and casting | S1 | 18% |
| Hot and cold rolling (reheating furnace, mill drives) | S2 | 12% |
| Iron ore and coal mining, beneficiation, and transport | S3 | 10% |
| Ancillary inputs (fluxes, refractories, alloys) | S3 | 5% |
Manufacturing Geography
- Region
- China (primary), EU, India, Japan, USA
- Grid Intensity
- 565 gCO2e/kWh (IEA 2024, China)
Material Composition Assumptions
The default reference product is 1 kg of hot-rolled structural steel or sheet metal produced via the blast furnace–basic oxygen furnace (BF-BOF) route, the dominant global production method (~70% of world output):
- Iron ore: Approximately 1.4 kg of iron ore (hematite or magnetite) per kg of crude steel, pelletized or sintered before charging to the blast furnace.
- Metallurgical coke: Approximately 0.35-0.45 kg of coke per kg of crude steel, produced from coking coal. Coke serves as both the reducing agent and fuel in the blast furnace.
- Limestone flux: Approximately 0.05-0.1 kg per kg of steel for slag formation and impurity removal.
- Alloying elements: For structural steel (e.g., A36, S275), small additions of manganese (~1.0%) and silicon (~0.3%). Sheet metal may include zinc coating (galvanized) adding ~0.02 kg/kg.
The BF-BOF route is inherently carbon-intensive because it relies on the chemical reduction of iron oxide by carbon (coke), producing CO2 as a fundamental process emission — not merely an energy-related emission.
Manufacturing Geography
Steel is produced globally with strong regional concentration:
- China: ~55% of global production, predominantly BF-BOF. Major steel regions include Hebei, Jiangsu, and Shandong provinces.
- India: ~6% of global production, growing rapidly. Mix of BF-BOF and DRI-EAF.
- EU: ~7% of global production. Mix of BF-BOF (ArcelorMittal, Tata Steel) and EAF (scrap-based mini-mills).
- USA: ~5% of global production. Heavily EAF-based (~70% of US steel is EAF).
- Grid intensity (China): 565 gCO2e/kWh (IEA 2024). Default for the global average product.
- Rationale: Scope 1 process emissions from coke combustion in the blast furnace dominate the total footprint. Grid intensity primarily affects the rolling and finishing stages and is a secondary factor.
Regional Variation
| Production Route / Region | Estimated Score (per kg) | Adjustment vs Default |
|---|---|---|
| China BF-BOF (default) | 2.0 kgCO2e | Baseline |
| EU BF-BOF | 1.8 kgCO2e | -10% (cleaner grid, higher efficiency) |
| India BF-BOF | 2.5 kgCO2e | +25% (less efficient plants, coal-heavy) |
| USA EAF (scrap-based) | 0.5 kgCO2e | -75% (scrap displaces ore+coke) |
| Sweden (HYBRIT / H2-DRI) | 0.4 kgCO2e | -80% (hydrogen replaces coke) |
Note: The BF-BOF vs. EAF route distinction is far more important than grid intensity. EAF steel from scrap is approximately 75% lower carbon than BF-BOF virgin steel.
Provenance Override Guidance
A supplier may override the default CCI score by submitting:
- Environmental Product Declaration (EPD) per EN 15804 for the specific steel product (hot-rolled coil, cold-rolled sheet, structural section).
- Production route data: BF-BOF vs. EAF vs. DRI-EAF. EAF with high scrap content dramatically reduces emissions.
- Mill-level CO2 intensity: Many steel companies now publish site-level carbon intensity (e.g., ArcelorMittal, SSAB, Nucor).
- ResponsibleSteel certification: Site-level certification covering GHG emissions performance.
- Green steel certification: Products made via hydrogen-based direct reduction (H2-DRI) or CCS-equipped routes.
Methodology Notes
- CCI score of 2 kgCO2e/kg represents the global average for BF-BOF hot-rolled steel, consistent with World Steel Association LCI data (2.0-2.3 kgCO2e/kg) and IEA benchmarks (~2.0 tCO2/t).
- Scope breakdown: Scope 1 dominates at 75% (1.5 kgCO2e/kg) — almost uniquely high among product categories — because the blast furnace chemical reduction of iron ore by carbon is an inherent process emission. Scope 2 is 15% (0.3 kgCO2e/kg) from rolling mill electricity. Scope 3 is 10% (0.2 kgCO2e/kg) from upstream mining and transport.
- Confidence: High because steel has the most extensive LCA and EPD dataset of any industrial material, with World Steel Association providing standardized global LCI data.
- Functional unit: 1 kg of hot-rolled structural steel or sheet, cradle to gate.
- End-of-life credit: Steel is highly recyclable (~85% global recycling rate). End-of-life recycling credits are excluded from the cradle-to-gate score per the cut-off allocation approach.
Related Concepts
Related Categories
Sources
- World Steel Association (2023) — Life Cycle Inventory Study — 2023 Data Release. Reports global average BOF steel at 2.0-2.3 kgCO2e/kg of hot-rolled coil, and EAF steel at 0.4-0.7 kgCO2e/kg depending on grid and scrap input.
- Hasanbeigi et al. (2014) — Comparison of carbon dioxide emissions intensity of steel production in China, Germany, Mexico, and the United States. Resources, Conservation and Recycling, 83, 47-60. Reports Chinese BF-BOF route at ~2.2 tCO2/t crude steel.
- IEA (2022) — Iron and Steel Technology Roadmap. Reports global average steel production emissions of ~1.8 tCO2/t steel, with BF-BOF route at ~2.0 tCO2/t and scrap-EAF at ~0.4 tCO2/t.
- EPD International (Various) — Environmental Product Declarations for hot-rolled and cold-rolled steel from ArcelorMittal, Tata Steel, SSAB. BOF route GWP typically 1.8-2.4 kgCO2e/kg.
- GHG Protocol (2014) — Scope 3 Calculation Guidance. Emission factors for purchased steel and metal materials.