Low carbon aluminium factsheet

There is an increasing demand from key stakeholders for guidance or clearer definitions around low-carbon, green or near-zero aluminium. Generally, there is broad alignment in the industry to IAI’s methodology for reporting carbon footprint. Marketing of brands commonly reference a carbon footprint of up to 4 tonnes CO2e per tonne primary aluminium as being low carbon. 

However, there is currently no definitive low carbon aluminium standard that specifies both the carbon footprint threshold and the measurement methodology.  Some low carbon aluminium brands offer a product with a footprint of up to 4 t CO2e/t primary Al that is ostensibly consistent with the IAI Carbon Footprint Methodology; others offer a product also nominally at 4 t CO2e footprint but not including all emission sources. 

 

THE CURRENT LOW CARBON ALUMINIUM LANDSCAPE  

The growing demand for low carbon aluminium and pressure on aluminium manufacturers to meet climate goals is driving the creation of a green aluminium market. This has resulted in producers launching low carbon aluminium brands, offering traceability and verified carbon footprint data.   

Across the aluminium industry, a carbon footprint up to 4 tonnes CO2e per tonne primary aluminium is a common reference among low carbon branded products, representing what is considered to be the very lowest achievable at commercial scale with currently available technologies and carefully selected supply chains. However, there is a lack of consistency regarding what is being included in the carbon footprint. For example, some low carbon aluminium brands offer a product with a footprint of up to 4 t CO2e/t primary Al that includes emissions broadly equivalent to Scope 1, Scope 2 and Scope 3 in corporate accounting terms; others offer a product of the same 4 t CO2e footprint with the exclusion of other indirect emission sources (broadly equivalent to Scope 3 in corporate accounting terms). The table below demonstrates the variability of products across the current low carbon aluminium landscape:  

	CO2 footprint (emissions intensity)	Emissions scope	Traceability	Industry global average benchmark referenced
Low carbon aluminium products	≤ 4 t CO2e/ t Al	Scope 1 & Scope 2	Mine to metal; third-party verified	12.2 t CO2e/ t Al
	≤ 4 t CO2e/ t Al	Scope 1, Scope 2 & Scope 3	Mine to metal; third-party verified	16.7 t CO2e/ t Al
	< 4 t CO2e/ t Al	Scope 1 & Scope 2	Cradle-to-gate; third-party verified	13.2 t CO2e/ t Al
	≤ 4 t CO2e/ t Al	Smelter (Scope 1 & 2) emissions only	Traceable to a single smelter; third-party verified	12.5 t CO2e/ t Al
	4 t CO2e / t Al	Smelting and casting (Scope 1 & 2) emissions only	Third-party verified	12.46 t CO2e/t Al
	4 t CO2e / t Al	Scope 1 & Scope 2	Mine to metal; third-party verified	18 t CO2e/t Al

First Movers Coalition (FMC), a global coalition of companies leveraging their purchasing power to decarbonise the world’s heavy-emitting sectors, define low carbon primary aluminium with the following criteria: emitting less than 3 t CO2 per tonne of aluminium produced, including all emissions from cradle to gate. This includes GHG emissions across all upstream processes including mining, refining, anode production, electrolysis, and casting; including GHG emissions from electricity, direct emissions, GHG emissions from thermal energy, transport and ancillary materials, aligned with IAI’s Carbon Footprint Methodology. Primary aluminium with such low carbon footprint would likely be accomplished using breakthrough technologies, such as inert anodes, CCUS, green hydrogen, mechanical vapour recompression (MVR)*. While Aluminium Stewardship Initiative (ASI) does not set any low carbon definitions, entities certified to its Performance Standard are required to ensure a GHG emissions reduction pathway consistent with a 1.5-degree scenario.  
*The IAI are tracking such technologies across the aluminium sector globally via our Innovations Map.

Other definitions are listed below:  

Company	Indicator	Carbon footprint threshold	Boundary
FMC	Aluminium commitment	3 t CO2e /t primary Al	Scope 1, 2 & 3 (upstream)
Harbor Aluminum	Green aluminium spot premium	4.5 t CO2e /t primary Al	Scope 1 & 2 emissions of smelter
Platts	Low-carbon aluminium price (LCAP)	4 t CO2e /t primary Al	Scope 1 & 2 emissions of smelter

INCOMPLETE CARBON FOOTPRINTS TO FIT A ‘LOW CARBON DEFINITION’ 

In order to fully assess the carbon footprint of primary aluminium, companies need to include the full scope of GHG emissions from cradle-to-gate, or mine-to-metal – assessing a product’s footprint from raw material extraction until it leaves the factory as primary metal ingot or equivalent. This includes both direct and indirect emissions for the production process and inputs, or in corporate carbon accounting terms, equivalent to Scope 1, Scope 2 and Scope 3 (including production of ancillary materials, production of fuel, waste processing and upstream transport) emissions.  

In some instances, products being claimed as low carbon are supported with incomplete carbon footprints to meet demands for products of 4 t CO2e or less and thus omit some emissions from the scope defined by the IAI’s Carbon Footprint Methodology. This could include:  

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

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

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

 

IAI’s carbon footprint FAQ answers common questions regarding comprehensive aluminium carbon footprints and features a checklist for all primary aluminium emissions sources.  

Link to Carbon footprint FAQ 

INDICATIVE EMISSIONS FOR SMELTERS GLOBALLY  

The chart below shows 150 smelters operating in 2019 and the respective emissions intensity (t CO2e/t Al) on the vertical axis. Note that the emissions shown only include a subset of cradle-to-gate emissions. These include electricity emissions, PFC emissions, CO₂ direct emissions, emissions from ancillary materials, emissions from anode production, casting and transport of alumina to the smelter and do not include emissions for mine to refinery. It does however provide a good overall indication of the current volume of primary aluminium that is being produced globally by smelters with relatively low emissions. The lowest emission intensity smelters are shown at the left side of the curve (1^st quartile) and account for 14.9 Mt of global primary aluminium production.  

LOWEST FOOTPRINT BASED ON CURRENT TECHNOLOGY  

The lowest reported emissions per unit processes from the IAI’s 2019 Life Cycle Inventory (LCI) survey are shown below. This data is not representative of a single site or carbon footprint – rather it is the lowest reported footprint for each unit process individually, from sites that report to the IAI.  

Unit process	Lowest reported footprint  (t CO2e/ t Al)
Mining	0.004
Refining	0.6
Anode production	1.38
Electrolysis	1.8
Casting (primary)	0.03

LOW CARBON ALUMINIUM VS CLIMATE-ALIGNMENT  

Alongside low carbon products, there has also been an increase in climate aligned products. Total aluminium sector GHG emissions in 2023 were approximately 1.1 billion tonnes of carbon dioxide equivalent (Gt CO2e), with an average GHG intensity of 14.8 t CO2e per tonne of primary aluminium. Primary aluminium production (mining to ingot casting) contributes to 95% of these total emissions.  Under a scenario which limits global warming to 1.5-degrees above pre-industrial levels, the aluminium sector must reduce its GHG emissions from over a billion tonnes of CO2e to around fifty million tonnes by 2050.  

	2023	2030	2035	2040	2045	2050	2023-2030	2023-2040	2023-2050
Primary aluminium*	14.8	11.5	4.2	2.2	1.2	0.5	-22%	-85%	-97%

*CO2e emissions intensity (tonnes per tonne). This data is available via IAI and is updated on an annual basis. Link to IAI statistics 

To achieve this 1.5-degree alignment, emissions intensity for primary aluminium will need to rapidly decrease over the years – by 22% to 2030 and 97% reduction to 2050. Looking ahead to 2035 and beyond, even the current low carbon aluminium producers will be required to reduce their emissions intensity numbers to reach a net zero future. Thus, as the context changes and new technologies emerge, the definitions of what is currently perceived as low carbon aluminium will likely change as well.   

SCIENCE BASED TARGETS 

The aluminium industry recognises the need to limit global warming to 1.5 degrees above pre-industrial levels, as set out in the Paris Agreement. Many aluminium companies have committed to ambitious reduction targets reflecting this. Many of these are in line with the GHG reduction pathways towards 2050 as defined by IAI’s Aluminium Industry GHG Pathways to 2050, outlining 2-degree and 1.5-degree Paris-aligned pathways which are regarded as science based. The IAI decarbonisation pathways have also been adopted by third-party initiatives including Aluminium Stewardship Initiative (ASI), Mission Possible Partnership (MPP) and Rocky Mountain Institute (RMI) and are supported by the global aluminium industry. 

The Science Based Targets Initiative (SBTi) launched in 2015 and has gained some traction amongst the industry’s stakeholders. SBTi validates company climate targets and their alignment with the 1.5-degree scenario using two methods: a contraction approach and a sectoral decarbonisation approach (SDA). The contraction approach is not appropriate for aluminium companies as decarbonisation necessitates new technologies and breakthroughs in current operating norms. Furthermore, an SDA for the aluminium sector has not been developed by SBTi, making it unsuitable as a framework for validating many aluminium company climate targets.