Guidance on calculating product carbon footprints under ISO 14067

1. What is a carbon footprint?

A carbon footprint is the total amount of greenhouse gases, including CO2, CH4, N2O and other gases, emitted directly and indirectly throughout a product’s life cycle, from raw material extraction, manufacturing, transport and use through to end-of-life treatment.

2. Benefits of calculating a carbon footprint

• Meet international standards: Standards such as ISO 14067 and PAS 2050 require carbon footprint reporting.
• Optimise production processes: Help businesses identify high-emission stages for improvement.
• Gain a competitive advantage: Enhance brand reputation through transparency and a commitment to reducing emissions.
• Meet legal requirements: Align with sustainability policies in major markets such as the EU and the United States.

3. The product carbon footprint calculation process

Step 1: Define the calculation boundary

The boundary for calculating a product carbon footprint (CFP) should be defined using a product life-cycle approach.

Two commonly used CFP life-cycle boundaries are:

1 – Calculate the product carbon footprint across its entire life cycle (cradle-to-grave).

2 – Calculate the product carbon footprint for part of its life cycle (cradle-to-gate), from raw material extraction to manufacture of the product ready for delivery to the customer. This boundary excludes product delivery, use and end-of-life processes.

Businesses commonly choose cradle-to-gate as the boundary for CFP quantification and disclosure.

Step 2: Collect data

Collect data relating to the stages of the product life cycle.

• Raw material extraction: Quantities of materials used and extraction methods.
• Production processes: Consumption of energy, water and other resources.
• Transport: Transport distances, vehicle types and energy consumption.
• Product use: Energy consumption during the use phase.
• End-of-life treatment: Recycling rates and waste treatment.

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Step 3: Convert data into emissions using emission factors

Use emission factors to convert activity data into quantities of greenhouse gas emissions. Common sources include:

• DEFRA (the UK environment department).
• IPCC (Intergovernmental Panel on Climate Change).
• Ecoinvent (a global LCA database).

Examples:

• Petrol: 1 litre of petrol emits 2.31 kg CO2.
• Grid electricity: 1 kWh of electricity emits 0.6766 kg CO2 (apply the national grid emission factor appropriate to the time of CFP quantification).

Step 4: Calculate total emissions

Use the formula:

Carbon footprint = ∑(Activity data × Emission factor)

Apply this formula to each stage of the product life cycle to aggregate emissions.

Step 5: Report results in accordance with international standards

Once calculations are complete, present the results clearly and transparently in accordance with standards such as:

• ISO 14067: International standard on the carbon footprint of products.
• PAS 2050: A standard for product life-cycle assessment.

4. Tools for calculating carbon footprints

Popular software tools that help businesses perform accurate calculations include:

• SimaPro: Life-cycle assessment (LCA) and carbon footprint calculations.
• OpenLCA: An open-source LCA tool.
• GHG Protocol Tools: Emission calculation guidance and tools.
• Carbon Trust Footprint Calculator: Simplifies the calculation process.

5. Tips for calculating a carbon footprint

• Ensure data accuracy: More detailed data lead to more accurate results.
• Update emission factors: Regularly check and update emission factor information.
• Consider the full life cycle: Do not overlook any stage of the product life cycle.
• Seek expert support: For complex products, assistance from an LCA expert helps ensure accuracy.

6. Conclusion

Calculating a product carbon footprint is an essential step towards sustainable development. It helps businesses reduce their environmental impacts and improve their competitiveness in global markets. Standardised processes and supporting tools are key to accurate and reliable results.