Aluminium Carbon Footprint FAQs

What is the carbon footprint of primary aluminium?  

The IAI specifies a cradle-to-gate approach to assess a product’s carbon footprint from raw material extraction until it leaves the factory. It includes all direct and indirect emissions for the production process and inputs.  

How is the carbon footprint calculated? 

The carbon footprint is calculated by measuring the CO₂ equivalent of all emissions from each upstream unit process involved in the production of primary aluminium.  This includes not only CO₂ but also other greenhouse gases (GHGs) such as perfluorocarbons (PFCs). 

What are the components of the carbon footprint of primary aluminium?  

For primary aluminium this includes the following unit processes: mining, refining (hydrate production & calcination), anode production, electrolysis, ingot casting, raw materials transport, electricity generation, and waste processing.    

What are the CO₂e ranges of each unit process involved in the production of primary aluminium?  

The IAI 2019 LCI survey provides a good reference for the range in GHG emissions intensity of each unit process that contributes to the carbon footprint of primary aluminium: 

Unit process	Surveyed range (t CO2e / t product*)
Mining	0.004 – 0.05
Refining	0.6 – 2.4
Anode production	0.9 – 3.8
Electrolysis	1.9 – 23.6
Casting (primary)	0.03 – 0.7

* tonne product refers to product at each unit process, e.g. mining is tonnes of bauxite, refining is tonnes of alumina, and smelting is tonnes of primary aluminium. On average, 4-6 tonnes of bauxite will produce 2 tonnes of alumina, which will produce 1 tonne of primary aluminium (varies depending on location).  

What is the typical range of a cradle-to-gate carbon footprint for primary aluminium?  

Most of the cradle-to-gate carbon footprints for primary aluminium will fall in the range 4.5–22 t CO₂e per tonne primary aluminium. However, by carefully organising the supply chains and achieving the best available performance for each unit process, the carbon footprint can be reduced to 4 t CO₂e per tonne or less. 

Link to Low Carbon Aluminium Factsheet 

Which sources of emissions does this range include? What are the associated indicative ranges?  

Transport	0.2 – 0.5 t CO2e/t Al**
Ancillary materials	0.9 – 1.6 t CO2e/t Al
Electricity	0.2 – 18 t CO2e/t Al
Thermal energy	1.2 – 3.8 t CO2e/t Al
Direct process	– 2.8 t CO2e/t Al

** note this is expressed in tonnes of aluminium not product as per the previous table.  

Which of the sources has the highest variability of emissions? 

As seen above, the major source of variability is for electricity related emissions. For example, emissions from hydropower will be lower when compared to emissions from gas-fired or coal-fired power.   

What would indicative cradle-to-gate carbon footprints of primary aluminium from different electricity sources look like?  

What is the difference between corporate reporting of GHG emissions and product carbon footprint?  

The fundamental difference between corporate GHG reporting and product carbon footprint lies in their scope and methodology—company-wide versus product-specific. Product carbon footprint calculates emissions associated with individual aluminium products through the production process (irrespective of the corporate ownership of the process elements), enabling product-level comparisons. Corporate reporting captures a company’s total operational and value chain emissions (across Scopes 1,2, and 3) and considers corporate ownership of each process element, supporting sustainability goals and compliance requirements. 

	Corporate Reporting of GHG Emissions	Product Carbon Footprint
Scope	Emissions from all company operations (Scope 1, 2, and 3)	Emissions associated with the entire lifecycle of a specific product, irrespective of the corporate ownership of the process elements
Purpose	Transparency and accountability for the company’s overall emissions, tracking sustainability progress	Assess and reduce the environmental impact of a particular product
Scope of Impact	Includes all operations, facilities, and business activities	Focuses on emissions from a single product’s lifecycle (production, use, disposal)
Measurement Focus	Company-wide emissions across all activities	Product-specific emissions at each life cycle stage
Audience	Investors, regulators, environmental organizations, and stakeholders	Consumers, product designers, sustainability teams, and manufacturers
Standards and Frameworks	Greenhouse Gas Protocol, ISO 14064, CDP	ISO 14067, PAS 2050

Under the GHG Protocol, corporate GHG accounting categorises emissions into three ‘Scopes’. What do the different Scopes refer to in terms of emissions?  

These Scopes refer to different categories of emissions: 

• Scope 1: Direct emissions generated by the company from owned or controlled sources. 

• Scope 2: Indirect emissions from the electricity, steam, heating, and cooling purchased by the company. 

• Scope 3: All other indirect emissions, such as those from the supply chain, employee business travel, and product use. 

What are the equivalent scopes for each unit process that contributes to the carbon footprint of primary aluminium?  

The figure below shows broadly equivalent corporate accounting scopes (Scopes 1, 2 and 3). It is important to note that product carbon footprints may not align precisely with corporate scopes and may differ from company to company dependent on corporate structure.  

What are some common mistakes to watch out for that may signal an incomplete carbon footprint of primary aluminium?  

Differences that warrant attention may include:  

• Omitting emissions outside the facilities directly owned, i.e. disclose Scope 1 & 2 only.  

• Overlooking emissions generated upstream of aluminium smelting, e.g. not including mining-related emissions.  

• Inadequate accounting for Scope 3 emissions, e.g. not including the emissions associated with the production and transportation of ancillary materials such as sodium hydroxide (which are used in the production process). 

Is there an emissions checklist for producers to use with their consumers that uses the cradle-to-gate approach?   

An IAI-aligned carbon footprint includes every category below. Data shown is the global average for 2023. Note that for some regions, the data may vary significantly in comparison to the global average due to factors such as electricity source. Global average data is provided per tonne of aluminium. As a general rule, to calculate the global average per tonne of product, 4-6 tonnes of bauxite will produce 2 tonnes of alumina, which in turn will produce 1 tonne of primary aluminium (ratio varies depending on location). 

PRIMARY ALUMINIUM CARBON FOOTPRINT CHECKLIST 

Emissions Source	Global Average (2023) in t CO2e/t Al	Included in carbon footprint number?
Mining – electricity	0.02
Mining – thermal energy	0.05
Refining – electricity	0.2
Refining – ancillary materials	0.4
Refining – thermal energy	1.5
Refining – transport	0.3
Anode production – electricity	0.05
Anode production – process	0.1
Anode production – ancillary materials	0.8
Anode production – thermal energy	0.1
Electrolysis – electricity	8.6
Electrolysis – PFC	0.8
Electrolysis – process	1.5
Electrolysis – ancillary materials	0.1
Electrolysis – transport	0.2
Casting – electricity	0.08
Casting – thermal energy	0.1
Total (cradle-to-gate)	14.8

Where can I find global data on GHG emissions intensity for primary aluminium?  

The IAI publishes global primary aluminium GHG emissions intensity data annually, available on the IAI website. There is also industry data available to calculate carbon footprint in software such as Sphera LCA for Experts (LCA FE, formerly Gabi) and ecoinvent. 

Link to IAI emissions intensity data  

What is the difference between emissions intensity and total emissions?  

Emissions intensity refers to emissions per production unit (i.e. tonnes of CO2 emitted per tonne of primary aluminium produced). Total emissions refer to annual emissions from all unit processes involved in the production of all aluminium. This could be presented at a site level, company level, regional level or global level.   

My supplier can only provide Scope 1 & 2 emissions. Is there a way to estimate Scope 3 emissions if data is not available or supplied?   

The IAI’s Scope 3 Calculation Tool is designed to evaluate Scope 3 emissions for the aluminium value chain. This tool utilises the user’s input data and default emission factors tailored for various stages of the aluminium value chain, which are instrumental in estimating emissions when primary data is not readily available.  

If no input data is available to utilise the Scope 3 Calculation Tool, a high level estimate based on the 2023 global average emissions data is approximately 2 t CO₂e/t Al. This number does not include anode production and may vary depending on the region.