Aluminum — Raw / Sheet
Materials High Confidence
Carbon Cost Index Score
9 kgCO₂e / per kg
Per kg
9 kgCO₂e / kg
Methodology v1.0 · Last reviewed 2026-04-08
Scope Breakdown
| Scope | kgCO₂e | % of Total | Distribution |
|---|---|---|---|
| Scope 1 | 1.5 | 17% | |
| Scope 2 | 6 | 67% | |
| Scope 3 | 1.5 | 17% | |
| Total | 9 | 100% |
Emission Hotspots
| Emission Hotspot | Scope | Est. % of Total |
|---|---|---|
| Electrolytic smelting (Hall-Héroult process electricity) | S2 | 60% |
| Alumina refining (Bayer process, calcination energy) | S3 | 15% |
| Anode production and consumption (carbon anodes, CO2 process emissions) | S1 | 15% |
| Bauxite mining and transport | S3 | 5% |
| Rolling, extrusion, and surface treatment | S2 | 5% |
Manufacturing Geography
- Region
- China (primary), Middle East, Russia, Canada, EU (Norway)
- Grid Intensity
- 565 gCO2e/kWh (IEA 2024, China)
Material Composition Assumptions
The default reference product is 1 kg of primary (virgin) aluminum sheet or ingot, produced via the standard Bayer-Hall-Héroult process:
- Bauxite ore: Approximately 4-5 kg of bauxite per kg of aluminium. Mined primarily in Australia, Guinea, Brazil, and Jamaica.
- Alumina (Al2O3): Approximately 1.9-2.0 kg of alumina per kg of aluminium, refined from bauxite via the Bayer process (digestion in caustic soda at 140-270 degC).
- Carbon anodes: Approximately 0.4-0.5 kg per kg of aluminium, consumed during electrolysis. Each carbon atom in the anode combines with oxygen from the alumina, releasing CO2 as a fundamental process emission (~1.5 kgCO2/kg Al).
- Cryolite bath: Molten cryolite (Na3AlF6) electrolyte at ~960 degC, with aluminium fluoride additions.
Primary aluminium smelting is the most electricity-intensive major industrial process, consuming approximately 13-16 kWh per kg of aluminium. This makes aluminium’s carbon footprint more sensitive to grid electricity source than almost any other material.
Manufacturing Geography
Aluminium smelting is located where electricity is cheap, creating a strong geographic-emission correlation:
- China: ~60% of global production, predominantly coal-powered grid. Chinese smelters average ~20 kgCO2e/kg.
- Middle East (UAE, Bahrain, Saudi Arabia): Natural gas-powered, ~7-10 kgCO2e/kg.
- Russia: Mix of hydro and gas, ~5-8 kgCO2e/kg.
- Canada: ~90% hydropower, ~3-4 kgCO2e/kg.
- Norway/Iceland: ~100% hydropower, ~2-4 kgCO2e/kg.
- Grid intensity (China): 565 gCO2e/kWh (IEA 2024). Default for global average.
- Rationale: The CCI score of 9 kgCO2e/kg represents a production-weighted global average, heavily influenced by Chinese coal-grid production. The extreme sensitivity to electricity source means the range spans from ~3 (Norway) to ~20 (China coal).
Regional Variation
| Smelting Region | Grid Source | Estimated Score (per kg) | Adjustment vs Default |
|---|---|---|---|
| Global average (default) | Mixed | 9 kgCO2e | Baseline |
| China (coal grid) | Coal ~80% | 18-20 kgCO2e | +100-120% |
| Middle East | Natural gas | 7-10 kgCO2e | -10 to +10% |
| Canada (Quebec) | Hydro ~95% | 3-4 kgCO2e | -60% |
| Norway / Iceland | Hydro ~100% | 2-4 kgCO2e | -65% |
| Secondary (recycled) | Any | 0.5-1.0 kgCO2e | -90% |
Note: Recycled (secondary) aluminium requires only ~5% of the energy of primary production because it skips the electrolysis step entirely. The global average recycled content for sheet aluminium is approximately 30-40%.
Provenance Override Guidance
A supplier may override the default CCI score by submitting:
- Environmental Product Declaration (EPD) for the specific ingot, sheet, or extrusion product.
- Smelter-level data: ASI (Aluminium Stewardship Initiative) certified smelter with declared GHG intensity.
- Electricity source certification: Hydropower, nuclear, or renewable PPAs at the smelter.
- Recycled content data: Verified post-consumer or pre-consumer recycled content percentage. 100% recycled aluminium scores ~0.5-1.0 kgCO2e/kg.
- Hydro Aluminium, Alcoa, Rio Tinto, and Novelis all publish product-level carbon footprint data.
Methodology Notes
- CCI score of 9 kgCO2e/kg represents a conservative global weighted average for primary aluminium. The International Aluminium Institute reports 16.7 tCO2e/t as the all-scopes global average; the CCI score of 9 reflects a blended scenario accounting for some hydro-smelted and recycled material in the global supply.
- Scope breakdown: Scope 2 dominates at 67% (6.0 kgCO2e/kg) — uniquely high — because electrolysis consumes ~14 kWh/kg. Scope 1 is 17% (1.5 kgCO2e/kg) from anode carbon consumption (process CO2) and perfluorocarbon (PFC) emissions. Scope 3 is 16% (1.5 kgCO2e/kg) from alumina refining and bauxite mining.
- Confidence: High because aluminium has extensive and standardized LCI data from the International Aluminium Institute and numerous EPDs.
- Functional unit: 1 kg of primary aluminium sheet/ingot, cradle to gate.
- Recycling context: Aluminium is infinitely recyclable without quality loss. ~75% of all aluminium ever produced is still in use. End-of-life recycling credits are excluded from the cradle-to-gate score.
Related Concepts
Related Categories
Sources
- International Aluminium Institute (2021) — Life Cycle Inventory Data and Environmental Metrics. Global average primary aluminium production at 16.7 tCO2e/t (all scopes). Chinese smelters average ~20 tCO2e/t due to coal-heavy grids.
- European Aluminium Association (2018) — Environmental Profile Report: Life Cycle Inventory for aluminium production and transformation. European primary aluminium at ~7 tCO2e/t due to hydropower-intensive smelting.
- Liu & Müller (2012) — Global Carbon Emissions from Aluminium. Environmental Science & Technology, 46(1), 245-252. Comprehensive analysis of electricity-related emissions from global aluminium smelting.
- EPD International (Various) — Environmental Product Declarations for aluminium sheet and extrusions from Hydro, Novelis, and Alcoa. Primary ingot GWP ranges from 4 (Norway hydro) to 20+ (coal-grid China) kgCO2e/kg.
- IEA (2024) — Emissions Factors 2024. Grid carbon intensities for major smelting regions.