CBAM Steel & Aluminium Compliance Tool User Guide

Step-by-step instructions, input rules, and calculation logic.

📋 Tool Overview

This tool is designed to help users understand and calculate the embedded emissions of iron, steel, and aluminium products under the EU Carbon Border Adjustment Mechanism (CBAM). Below are the key information about the tool.

Sectors Supported by the Calculator
  • Iron and Steel
  • Aluminium
Data Source Priority
  1. Facility-specific measured data
  2. Regional emission factors
  3. CBAM default values
Disclaimer: This tool and the data and documents it generates are for educational purposes only. File downloads are intended to assist users in learning. Users should not enter any confidential information, nor share any data or documents with third parties, or use them for CBAM compliance.
📝 Product-specific Embedded Emissions - Inputs

This section describes the basic input information required for calculating product-specific embedded emissions (SEE). These inputs will form the framework for subsequent emission calculations.

Bubble Approach

The bubble approach determines how the boundaries for emission calculations are defined. You need to choose whether to use the bubble approach based on your facility's actual situation.

Selection Guide

  • Yes (Use Bubble Approach): Treat the entire facility as a "bubble," where all emissions are aggregated at the facility level and then allocated by product output. This is suitable when multiple production lines share emission sources.
  • No (Do Not Use Bubble Approach): Account for emissions from each production process separately. This is suitable when emission sources can be clearly attributed to specific products.

Data Entry Requirements

  • When selecting "Yes," ensure all relevant emission sources within the facility are included in the calculation scope
  • When selecting "No," enter emission data for each production process individually

Method A: Bubble Approach

The total emissions of the entire facility are allocated proportionally based on each product's output. This method is suitable for complex production environments where emission sources are shared and difficult to attribute directly to a single product.

Method B: Process-level Accounting

Emissions are calculated separately for each production process. This method provides more accurate product-level emission data and is suitable for facilities with clear emission source boundaries.

Sector

Select the sector to which your product belongs. This calculator currently supports the following sectors:

  • Iron and Steel: Including pig iron, crude steel, direct reduced iron (DRI), ferro-alloys, and various steel products
  • Aluminium: Including unwrought aluminium, aluminium products, and aluminium alloys

The sector selection will determine the available aggregated goods categories and production routes.

Aggregated Goods Category

Select the "aggregated goods category" of the goods produced in this process. Please match the HS code (CN code) with the goods category.

Aggregated goods category is a product grouping defined in CBAM regulations, classifying products with similar production processes and carbon emission characteristics.

Common Categories in Iron and Steel Sector

  • Pig Iron
  • Crude Steel
  • Direct Reduced Iron - DRI
  • Ferro-alloys - FeMn, FeCr, FeNi
  • Iron or Steel Products

Common Categories in Aluminium Sector

  • Unwrought Aluminium
  • Aluminium Products

Route Name

The production route describes the main process path from raw materials to final products. Please select the corresponding route based on the actual process used in your facility.

Main Routes in Iron and Steel Sector

  • BF-BOF Route: The traditional route using blast furnace for ironmaking and basic oxygen furnace for steelmaking
  • EAF Route: Route using electric arc furnace with scrap or DRI as raw materials
  • DR Route: Direct reduction of iron ore using natural gas or hydrogen

Main Routes in Aluminium Sector

  • Hall-Héroult Route: The standard smelting route where alumina is electrolyzed into aluminium metal
  • Secondary Route: Recycling route using scrap aluminium as raw material

The route name is used to identify your production process. You can use a custom name or select a preset route.

Production Volume

Enter the production volume of this production process during the reporting period (in tonnes).

  • Unit: Metric tonnes (t)
  • Range: Must be a positive number
  • Period: Consistent with the reporting period (usually a calendar year or a quarter)
Note: Production volume is the denominator for calculating specific embedded emissions (SEE). Ensure that the volume data covers the same time period and production boundaries as the emission data.
🔄 Source Streams Input

Source streams refer to material or energy flows in the production process that cause greenhouse gas emissions. This section guides you on how to enter calculation parameters for each source stream.

Method

Select the applicable emission calculation method for each source stream. CBAM provides three standard methods:

Combustion-based Method

Applicable to emissions from fuel combustion. Calculation formula:

Emissions = AD × NCV × EF × OxF

Where AD is fuel consumption, NCV is net calorific value, EF is emission factor, and OxF is oxidation factor.

Process-based Method

Applicable to emissions from chemical reactions (non-combustion), such as CO₂ released from limestone decomposition. Calculation formula:

Emissions = AD × EF × ConvF

Where AD is raw material consumption, EF is emission factor, and ConvF is conversion factor.

Mass Balance Method

Calculate emissions based on carbon balance of material inputs and outputs. Calculation formula:

Emissions = AD × CC × 44/12

Where AD is material quantity, CC is carbon content, and 44/12 is the molecular weight ratio of CO₂ to C.

Activity Data (AD)

Activity data refers to quantified data on materials or energy related to the source stream during the reporting period.

  • Unit: Select appropriate units based on material type (e.g., t, Nm³, GJ)
  • Data Source: Prioritize measured data from the enterprise's metering system
  • Accuracy: Data should be obtained using calibrated metering equipment
Important: Activity data can be negative. A negative value indicates that the source stream is a product/output stream (such as a by-product), and its carbon content will be deducted from the total emissions. For example, when blast furnace gas is output as a by-product, its AD should be entered as a negative value.

Net Calorific Value (NCV)

Net calorific value represents the effective heat energy released when fuel is completely combusted. This parameter is only required when using the combustion-based method.

  • Unit: GJ/t (solid and liquid fuels) or GJ/1000Nm³ (gaseous fuels)
  • Priority: Prioritize measured values or data provided by suppliers; if unavailable, refer to the IPCC default values in the table below

IPCC Default Net Calorific Value Reference Table

Fuel Type Default EF (tCO₂/TJ) Default NCV (GJ/t) Source
Crude Oil73.342.3IPCC 2006 GL
Orimulsion77.027.5IPCC 2006 GL
Natural Gas Liquids64.244.2IPCC 2006 GL
Motor Gasoline69.344.3IPCC 2006 GL
Kerosene71.943.8IPCC 2006 GL
Shale Oil73.338.1IPCC 2006 GL
Gas/Diesel Oil74.143.0IPCC 2006 GL
Residual Fuel Oil77.440.4IPCC 2006 GL
Liquefied Petroleum Gases63.147.3IPCC 2006 GL
Ethane61.646.4IPCC 2006 GL
Naphtha73.344.5IPCC 2006 GL
Bitumen80.740.2IPCC 2006 GL
Lubricants73.340.2IPCC 2006 GL
Petroleum Coke97.532.5IPCC 2006 GL
Refinery Feedstocks73.343.0IPCC 2006 GL
Refinery Gas57.649.5IPCC 2006 GL
Paraffin Waxes73.340.2IPCC 2006 GL
White Spirit & SBP73.340.2IPCC 2006 GL
Other Petroleum Products73.340.2IPCC 2006 GL
Anthracite98.326.7IPCC 2006 GL
Coking Coal94.628.2IPCC 2006 GL
Other Bituminous Coal94.625.8IPCC 2006 GL
Sub-bituminous Coal96.118.9IPCC 2006 GL
Lignite101.011.9IPCC 2006 GL
Oil Shale and Tar Sands107.08.9IPCC 2006 GL
Brown Coal Briquettes97.520.7IPCC 2006 GL
Coke Oven Coke & Lignite Coke107.028.2IPCC 2006 GL
Gas Coke107.028.2IPCC 2006 GL
Coal Tar80.728.0IPCC 2006 GL
Gas Works Gas44.438.7IPCC 2006 GL
Coke Oven Gas44.438.7IPCC 2006 GL
Blast Furnace Gas260.02.47IPCC 2006 GL
Basic Oxygen Furnace Gas182.07.06IPCC 2006 GL
Natural Gas56.148.0IPCC 2006 GL
Industrial Waste143.0n.a.IPCC 2006 GL
Waste Oil73.340.2IPCC 2006 GL
Peat106.09.76IPCC 2006 GL
Waste Tyres85.0n.a.WBCSD CSI
Carbon Monoxide155.210.1J. Falbe and M. Regitz, Römpp Chemie Lexikon, Stuttgart, 1995
Methane54.950.0J. Falbe and M. Regitz, Römpp Chemie Lexikon, Stuttgart, 1995
Wood/Wood Waste112.015.6IPCC 2006 GL
Sulphite Lyes95.311.8IPCC 2006 GL
Other Primary Solid Biomass100.011.6IPCC 2006 GL
Charcoal112.029.5IPCC 2006 GL
Biogasoline70.827.0IPCC 2006 GL
Biodiesels70.837.0IPCC 2006 GL
Other Liquid Biofuels79.627.4IPCC 2006 GL
Landfill Gas54.650.4IPCC 2006 GL
Sludge Gas54.650.4IPCC 2006 GL
Other Biogas54.650.4IPCC 2006 GL
Municipal Waste (biomass fraction)100.011.6IPCC 2006 GL

Emission Factor (EF)

Emission factor represents the greenhouse gas emissions per unit of activity data.

  • Combustion-based Method: Unit is tCO₂/TJ, representing CO₂ emissions per terajoule of heat
  • Process-based Method: Unit is tCO₂/t raw material, representing CO₂ emissions per tonne of raw material reacted

Data Source Priority

  1. Facility/enterprise-specific measured values
  2. Regional or national statistical emission factors
  3. IPCC default values (see reference table above)

Reference Resources

Other Factors

Depending on the selected method, the following additional factors may need to be entered:

Oxidation Factor (OxF)

  • Applicable Method: Combustion-based method
  • Definition: The proportion of carbon in fuel that is oxidized to CO₂
  • Range: 0% ~ 100%
  • Default Value: Usually assumed to be 100% (conservative estimate, assuming all carbon in fuel is fully oxidized)
  • Note: Only use values below 100% when reliable measured data shows incomplete carbon oxidation

Conversion Factor (ConvF)

  • Applicable Method: Process-based method
  • Definition: The proportion of carbon in raw material that is converted to CO₂ in the chemical reaction
  • Range: 0% ~ 100%
  • Default Value: Usually assumed to be 100% (conservative estimate)
  • Note: When the reaction is incomplete (e.g., partial limestone decomposition), the measured conversion rate can be used

Biomass Content (BioC)

  • Applicable Method: All methods
  • Definition: The proportion of carbon derived from biomass in fuel or raw material relative to total carbon
  • Range: 0% ~ 100%
  • Default Value: 0% (pure fossil fuel)
  • Note: Biomass carbon emissions are recorded separately under the CBAM framework and are not counted in total fossil carbon emissions. Accurately enter this ratio when using mixed fuels containing biomass

Carbon Content (CC)

Carbon content is only required when using the mass balance method, representing the mass fraction of carbon in the material.

  • Unit: tC/t material (mass fraction of carbon)
  • Range: 0 ~ 1
  • Purpose: Convert carbon mass to CO₂ mass through CC × 44/12

Data Source Priority

  1. Laboratory Analysis: Prioritize carbon content analysis results of actual material samples from certified laboratories
  2. Supplier Provided: Use carbon content data provided by the material supplier in quality certificates
  3. IPCC Default Values: When the above data is unavailable, refer to IPCC default carbon content values

Reference Resource: IPCC Emission Factor Database (EFDB) contains default carbon content values for various fuels and raw materials.

Energy Emissions Input

Energy emissions cover emissions related to measurable heat (steam, hot water, etc.). When the production process involves heat input or output, relevant data needs to be entered in this section.

Imports

Record measurable heat obtained from external sources during the production process. Includes the following two scenarios:

External Purchase (from outside facility boundary)

Steam, hot water, or other heat carriers purchased from external suppliers.

  • Data Requirements: Heat quantity (TJ or GJ), supplier's emission factor
  • Source: Invoices and emission data provided by suppliers
  • Note: If the supplier cannot provide emission factors, default values can be used

Internal Transfer (from other processes within the facility)

Heat received from other production processes within the same facility.

  • Data Requirements: Heat quantity (TJ or GJ), emission factor of the process generating the heat
  • Source: Internal metering systems and energy management records
  • Note: Ensure that the heat emissions have been accounted for in the source process to avoid double counting

Exports

Record measurable heat output to external sources during the production process. Emissions corresponding to exported heat will be deducted from the total emissions of this process.

Two Types of Exports

  • External Sale: Heat sold to third parties outside the facility boundary. The heat quantity and related emissions need to be recorded, and the emission amount will be deducted from this process.
  • Internal Transfer: Heat provided to other production processes within the same facility. The receiving process needs to include this heat in its "Imports".
Note: Emission deductions for heat exports must be based on actual emission factors, and deduction amounts must not be overestimated. Ensure consistency in heat accounting for imports and exports.

Emission Factor (EF)

The emission factor for heat represents the greenhouse gas emissions per unit of heat generated.

Internal Source

  • When heat is generated internally within the facility, the emission factor should be calculated based on actual fuel consumption and emission data for generating that heat
  • Calculation Method: Total emissions corresponding to the heat ÷ Total heat output

External Source

  • Prioritize using emission factors provided by the heat supplier
  • If supplier data is unavailable, the following alternatives can be used:
    • Average emission factor for the heating industry in the country/region
    • Default values specified in Annex III of (EU) 2023/1773
Note: Ensure that the unit of the emission factor (e.g., tCO₂/TJ) is consistent with the unit of heat input.
🧪 PFC Emissions Input

Perfluorocarbon (PFC) emissions are only relevant to aluminium smelting. PFCs (mainly CF₄ and C₂F₆) are produced during anode effects in the electrolysis process. CBAM provides two calculation methods: the slope method and the overvoltage method.

Slope Method

The slope method estimates PFC emissions based on the frequency and duration of anode effects. Below is the complete four-step calculation process:

1

Calculate CF₄ Emission Factor

Using anode effect frequency (AEF) and duration (AED), and slope emission factor (SEF):

EF(CF₄) = SEF × AEF × AED / 1000

Where:

  • SEF = Slope emission factor (kg CF₄/(t Al·AE-min/cell-day))
  • AEF = Anode effect frequency (times/cell·day)
  • AED = Anode effect duration (min/time)
  • Result unit: t CF₄/t Al
2

Calculate C₂F₆ Emission Factor

C₂F₆ emissions are usually estimated as a fixed proportion of CF₄:

EF(C₂F₆) = EF(CF₄) × F(C₂F₆)

Where F(C₂F₆) is the mass ratio coefficient of C₂F₆ to CF₄, depending on the smelting process type.

3

Convert to CO₂ Equivalent

Multiply CF₄ and C₂F₆ emissions by their respective global warming potentials (GWP):

PFC(CO₂e) = EF(CF₄) × GWP(CF₄) + EF(C₂F₆) × GWP(C₂F₆)

CBAM default GWP values (IPCC AR4):

  • GWP(CF₄) = 6630
  • GWP(C₂F₆) = 11100
4

Calculate Total PFC Emissions

Multiply the CO₂ equivalent emission factor by aluminium production:

Total PFC Emissions (tCO₂e) = PFC(CO₂e) × Aluminium Production (t)

Overvoltage Method

The overvoltage method estimates PFC emissions based on anode effect overvoltage during the electrolysis process. Below is the complete four-step calculation process:

1

Calculate CF₄ Emission Factor

Using anode effect overvoltage (AEO), current efficiency (CE), and overvoltage coefficient (OVC):

EF(CF₄) = OVC × AEO / (CE / 100) / 1000

Where:

  • OVC = Overvoltage coefficient (kg CF₄/(t Al·mV))
  • AEO = Anode effect overvoltage (mV)
  • CE = Current efficiency (%)
  • Result unit: t CF₄/t Al
2

Calculate C₂F₆ Emission Factor

Same as the slope method, C₂F₆ is estimated as a fixed proportion of CF₄:

EF(C₂F₆) = EF(CF₄) × F(C₂F₆)
3

Convert to CO₂ Equivalent

Use GWP values to convert PFC emissions to CO₂ equivalent:

PFC(CO₂e) = EF(CF₄) × GWP(CF₄) + EF(C₂F₆) × GWP(C₂F₆)

CBAM default GWP values (IPCC AR4):

  • GWP(CF₄) = 6630
  • GWP(C₂F₆) = 11100
4

Calculate Total PFC Emissions

Total PFC Emissions (tCO₂e) = PFC(CO₂e) × Aluminium Production (t)
📦 Purchased Precursors

Purchased precursors are intermediate products procured from external suppliers and consumed in the production process at this facility. The embedded emissions of precursors themselves need to be included in the total emissions of the final product.

Precursor SEE (Direct and Indirect)

The specific embedded emissions (SEE) of precursors include both direct and indirect emissions:

Direct SEE

  • Definition: Greenhouse gas emissions directly produced during precursor production (tCO₂e/t precursor)
  • Data Sources:
    1. Facility-specific data provided by supplier (preferred)
    2. Industry average for the country/region where the supplier is located
    3. Default values specified in CBAM regulations

Indirect SEE

  • Definition: Indirect emissions from electricity consumption during precursor production (tCO₂e/t precursor)
  • Data Sources:
    1. Actual electricity emission factor data provided by supplier
    2. Grid emission factor for the supplier's country
    3. Default values specified in CBAM regulations
Note: When suppliers cannot provide emission data, use the default values specified in CBAM regulations. Default values are typically based on the worst-performing facilities globally that produce the precursor, so they may be significantly higher than actual emission levels. It is recommended to obtain actual data from suppliers whenever possible.

AD Quantity

Record the quantity of purchased precursors consumed during the reporting period.

  • Unit: Tonnes (t)
  • Definition: The amount of precursor actually consumed in this production process (not purchase quantity)
  • Notes:
    • Quantity should be based on actual consumption, not purchase records
    • Inventory changes need to be considered
    • Ensure correspondence with the reporting period
Calculation Note: Emission contribution from purchased precursors = Precursor SEE (direct + indirect) × AD Quantity. This value will be added to the total embedded emissions of the final product.
🏭 Own Precursors

Own precursors are intermediate products produced within the same facility (or other facilities of the same company). Unlike purchased precursors, emission data for own precursors can be calculated directly based on actual production data.

Precursor SEE (Direct and Indirect)

The specific embedded emissions (SEE) of own precursors should be calculated based on actual emission data from their production process.

Direct SEE

  • Definition: Greenhouse gas emissions directly produced during precursor production (tCO₂e/t precursor)
  • Data Source: Calculated based on actual monitoring data from this facility's precursor production process, including:
    • All source stream emissions from precursor production process
    • Energy emissions involved in precursor production process
    • PFC emissions involved in precursor production process (if applicable)
  • Calculation: Direct SEE = Total direct emissions from precursor production / Precursor production volume

Indirect SEE

  • Definition: Indirect emissions from electricity consumption during precursor production (tCO₂e/t precursor)
  • Data Source: Calculated based on actual electricity consumption and applicable electricity emission factor for the precursor production process
  • Calculation: Indirect SEE = Total indirect emissions from precursor production / Precursor production volume
Note: Own precursor emission data is usually more accurate than purchased precursors because detailed production process data can be directly obtained. If the precursor itself also uses other precursors (nested precursors), the next level precursor emissions also need to be included in the calculation.

AD Quantity

Record the quantity of own precursors consumed in the final product production process during the reporting period.

  • Unit: Tonnes (t)
  • Definition: The amount of own precursor actually consumed in the final product production process
  • Notes:
    • Should be based on actual consumption (not production volume)
    • If the precursor has multiple downstream uses, allocate usage reasonably
    • Ensure consistency with the reporting period and final product production boundaries
Calculation Note: Emission contribution from own precursors = Precursor SEE (direct + indirect) × AD Quantity. This value will be added to the total embedded emissions of the final product. Unlike purchased precursors, the SEE here should be the actual value you calculated yourself.
📚 Glossary

Below are the professional terms and abbreviations commonly used in this tool to help you understand CBAM-related concepts and calculation parameters.

CBAM
Carbon Border Adjustment Mechanism
A trade policy instrument established by the EU to prevent "carbon leakage," requiring importers to purchase certificates for emissions embedded in products, ensuring imported products bear the same carbon costs as EU domestic products.
SEE
Specific Embedded Emissions
The greenhouse gas emissions contained in each tonne of product (tCO₂e/t), divided into direct and indirect emissions, is the core indicator for CBAM declarations.
AD
Activity Data
Quantified data on materials/energy consumed or produced in the production process, such as fuel consumption and raw material usage, is the basic input for calculating emissions.
NCV
Net Calorific Value
The effective heat energy released when fuel is combusted (after deducting latent heat losses such as water evaporation), in GJ/t or GJ/1000Nm³, used to convert fuel consumption to energy.
EF
Emission Factor
Greenhouse gas emissions per unit of activity data, such as tCO₂/TJ (tonnes of carbon dioxide emitted per terajoule), can come from measurement, regional statistics, or IPCC default values.
OxF
Oxidation Factor
The proportion of carbon in fuel that is completely oxidized to CO₂ (0~100%), usually assumed to be 100% as a conservative estimate.
ConvF
Conversion Factor
In process emission calculations, represents the proportion of carbon in raw material converted to CO₂ (0~100%), reflecting the actual conversion degree of chemical reactions.
BioC
Biomass Content
The proportion of carbon derived from biomass in fuel or raw material relative to total carbon (%). Biomass carbon emissions are recorded separately in CBAM and not counted in fossil carbon emissions.
CC
Carbon Content
The mass fraction of carbon in material, used for mass balance method calculations. Can be converted to CO₂ emissions by multiplying by 44/12 (molecular weight ratio of CO₂/C).
PFC
Perfluorocarbon
Potent greenhouse gases produced during anode effects in aluminium smelting (mainly CF₄ and C₂F₆), with global warming potentials much higher than CO₂.
GWP
Global Warming Potential
An indicator measuring the warming effect of greenhouse gases relative to CO₂. CBAM defaults to IPCC AR4 values: CF₄=6630, C₂F₆=11100.
CF₄
Tetrafluoromethane
The main PFC gas produced during anode effects in aluminium smelting, with a GWP of 6630, meaning 1 tonne of CF₄ has the greenhouse effect equivalent to 6630 tonnes of CO₂.
C₂F₆
Hexafluoroethane
A secondary PFC gas produced during anode effects in aluminium smelting, with a GWP of 11100, usually estimated by multiplying CF₄ emissions by the F(C₂F₆) coefficient.
AEF
Anode Effect Frequency
The frequency of anode effects occurring in aluminium electrolysis cells, measured in "times/cell·day", is a key parameter for calculating PFC emissions using the slope method.
AED
Anode Effect Duration
The average duration in minutes of each anode effect (min/time), which together with AEF determines the PFC emission factor under the slope method.
SEF
Slope Emission Factor
A coefficient specific to the smelting process in the slope method, in kg CF₄/(t Al·AE-min/cell-day), mapping anode effect parameters to CF₄ emissions.
AEO
Anode Effect Overvoltage
The difference between the actual working voltage and the baseline voltage without anode effect during electrolysis (mV), is the core measurement parameter for the overvoltage method.
CE
Current Efficiency
The percentage of current actually used for aluminium reduction in the electrolysis process relative to total current, reflecting electrical energy utilization efficiency, used for overvoltage method PFC calculations.
OVC
Overvoltage Coefficient
A process-specific coefficient in the overvoltage method that converts anode effect overvoltage to PFC emissions, in kg CF₄/(t Al·mV).
EU ETS
EU Emissions Trading System
The world's largest carbon market, pricing carbon emissions through a cap-and-trade mechanism. CBAM certificate prices are linked to EU ETS allowance auction prices.
EUA
EU Allowance
Tradable emission permits under the EU ETS, 1 EUA = the right to emit 1 tonne of CO₂e. CBAM certificate prices reference the weekly average EUA price.
IPCC
Intergovernmental Panel on Climate Change
A UN body that publishes authoritative greenhouse gas accounting guidelines (such as 2006 GL), whose emission factors and GWP values are widely cited by CBAM.
IEA
International Energy Agency
Provides authoritative energy data such as electricity emission factors for various countries, which can be used as an alternative data source when supplier data is unavailable.