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Decoding Product Carbon Footprints: Methodologies and Benefits
Blog
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January 16, 2025
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12
min read
What is a Product Carbon Footprint (PCF)?
A Product Carbon Footprint (PCF) is a technique for quantifying the greenhouse gas (GHG) emissions generated over the lifecycle of a specific commercial or industrial product. PCFs focus on the single impact category of climate change. They are one segment of Life Cycle Assessments (LCAs), which take a more comprehensive view, measuring additional environmental impact categories from ozone depletion to acidification of soils and water.
You can think of a PCF as a nutrition label for a product with only one nutrient: GHG emissions. In PCF terminology, the “serving size” is called a functional unit or declared unit (we dig into this more in the next section!).
Just as a nutrition label shows calories per serving size, a PCF aims to measure GHG emissions per functional (or declared) unit as an emissions intensity. How much CO2-equivalent (CO2eq) emissions were released per unit of product?
Below is an example of a PCF done for Tesco’s packaged juice, which has 260g of CO2eq per 250 mL (functional unit).
PCFs can be leveraged to achieve many goals, including:
In fact, robustly defining the goal of your PCF is the very first phase of conducting one.
There are multiple methodologies for performing PCFs as well as communicating them, but they all start with defining the goal and scope of your analysis: what you’ll study and how.
PCFs and LCAs serve as powerful means for organizations to simultaneously advance many corporate goals across sustainability, risk management, market competitiveness, stewardship, and industry reputation.
So, how do you leverage them?
How to Calculate PCFs: The Basics
Let’s walk through how a PCF is calculated.
Remember: when doing a PCF, we’re calculating the climate change impact (GHG emissions expressed in CO2eq) of all the processes that touch our product. This calculation follows the same basic formula as when calculating other company-related emissions:
𝑔ℎ𝑔𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠=𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝐷𝑎𝑡𝑎 𝑋 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝐹𝑎𝑐𝑡𝑜𝑟 𝑋 𝐺𝑊𝑃
Where:
- ghgEmissions is the mass of GHGs released, expressed in CO2eq.
- activityData is a physical or economic measure of activity levels. Examples include kWh of electricity used in a piece of factory equipment, km traveled along a shipping route, or dollars spent.
- emissionFactor is a factor for converting activity data into GHG emissions data. Examples include kg CO2, kg CH4, and kg N2O (equation above is used 3 times, once for each GHG) released per kWh of grid electricity used, or kgCO2e (combines all GHGs) per cubic meter of cement purchased – a factor you might source from a PCF or LCA done by your cement supplier!
- GWP is Global Warming Potential, a measure of the degree of atmospheric harm done by 1 unit of a given GHG relative to 1 unit of CO2. Multiplying the quantity of a GHG by its GWP converts that quantity into standard units of CO2-equivalents (CO2eq) and allows for summation of all GHG quantities into a single CO2eq quantity. CO2 has a GWP of 1. Be mindful that some emission factors are already expressed on a CO2eq basis, so the GWP conversion isn’t needed.
When calculating a PCF, a functional unit must be defined. A functional unit is a quantity of a product, e.g., 1 carton of pulp-free orange juice, that acts as a reference against which emissions from each process are measured. This allows for comparison and aggregation of impacts across all stages in the lifecycle of your product. If you’re doing a partial PCF, this unit is called a declared unit – same gist, but the reference unit is usually a specific mass or volume of a product rather than 1 unit, e.g., 1 cubic meter (m3) of cement.
Which Methodologies are Used to Calculate PCFs?
The figure below outlines six different methodology standards that could be used for a PCF as well as the interrelationships between them and related standards.
As illustrated, ISO 14040/14044 standards are the bedrock of any LCA (and thus PCF) and establish foundational principles and requirements. Conforming with ISO 14040/14044, different methodology standards elaborate on which methods to use when conducting a PCF. Published by international standard-setting organizations like ISO and national regulatory bodies, these methodologies vary in their granularity, comprehensiveness, and stringency around data collection and documentation. Further, while some are suited to all types of studies, others offer methods tailored to specific products or industries.
We recommend choosing a methodology standard based on (i) the type of product in question, (ii) the ambition of your company, (iii) the geographic area you serve, (iv) and the regulations within that area.
Interested in more detail on the PCF methodology landscape? See oursection at the end of this guide.
How Do You Define the Boundaries of a PCF?
Once a methodology is selected (based on a company’s goals and geography), a boundary needs to be defined. The boundary identifies which lifecycle stages and processes are included in the analysis.
The five main lifecycle stages are:
- Material acquisition & pre-processing
- Design & production
- Distribution & storage
- Use
- End-of-life
PCFs are normally calculated in one of the following ways:
- Cradle-to-gate (partial): takes into consideration all processes from extracting resources to be used in manufacturing your product up to the point when your product exits your factory “gate”.
- Cradle-to-grave (full): covers the full lifecycle of your product; this includes all the cradle-to-gate process plus emissions downstream of your company’s operations (e.g., disposal of your product once used).
After defining your boundary, you should develop a process map describing all the processes that make it possible for your product to perform its function.
Returning to our orange juice example, for a cradle-to-gate analysis, you’d elaborate all the processes that carry your raw materials to your factory, through your factory machinery, and up to your factory’s exit gates where packaged cartons are picked up for delivery to customers. Every process would have its own unique energy and material flows.
For example, during the process of juice extraction in the factory, whole oranges and electricity “flow in”, and wet peel, oil emulsion, and juice “flow out”.
A simplified version of a process map for a cradle-to-gate analysis of our orange juice is shown below. We also indicate how you’d expand your process map to conduct a cradle-to-grave analysis.
How Do You Collect the Right Data?
Recall that a PCF is the sum of emissions from the processes linked to your product, calculated by multiplying process activity data by an appropriate emission factor and GWP for each GHG. Here’s our handy equation from before:
𝑔ℎ𝑔𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠=𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝐷𝑎𝑡𝑎 𝑋 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝐹𝑎𝑐𝑡𝑜𝑟 𝑋 𝐺𝑊𝑃
This equation will look familiar if you’ve prepared a company-level GHG inventory (also called corporate carbon footprint) before.
Let’s say your orange juice factory is in Massachusetts. If you were calculating your company’s location-based Scope 2 emissions from purchased electricity, you’d multiply your electricity usage in your factory by a regional grid electricity emission factor, like EPA e-Grid NPCC New England, since power usage for your operations is a source of emissions over which your company has control or influence.
The same rules apply to your PCF. You’d still collect activity data on the electricity usage in your factory. However, you must be careful to measure (or allocate) the portion of that electricity usage involved in the making of a functional unit of your product. For example, while your company-level inventory includes all electricity usage at a factory, your PCF should only include electricity usage by machinery used in the processing of one functional unit of your product.
Because product-level emissions are a part of company-level emissions, you can use information collected for your company inventory to do a PCF, being careful to adhere to the PCF boundary and functional unit you’ve defined. To illustrate this point, we show below how a company’s Scope 1, 2, and 3 emissions encompass the emissions from all its products in their produced quantities – and thus how it follows that you can “attribute” or cascade these emissions down to each product.
Bonus Tips for PCF Methodology Selection
The abundance of PCF methodologies is promising. Regulatory bodies and industry groups are recognizing the value of product transparency, calculation consistency, and results interpretability.
But this land of abundance can also be disorienting, begging the question “which PCF methodology should you choose?”
In the section above, we presented six popular methodology standards, from ISO 14067 (the international reference standard for PCF) to PEF (the EU recommended method for product LCA).
In addition to these six standards, there are also methodological guidelines that provide more granular, product-specific or sector-specific instructions for conducting PCFs to drive comparability between PCFs.
These guidelines can take the form of Product Category Rules (e.g., PCR, PEFCR) or sector-specific guidance (e.g., Together for Sustainability, PlasticsEurope, Catena-X).
Understanding how and when to integrate product- or sector-specific considerations into your PCF study will depend on your defined study goal and the questions you’re intending to answer. Here are a few examples where more tailored standards or guidelines could be integrated:
- Are you a concrete manufacturer in the U.S. whose customers are working on government projects?
- If so, then the ISO 21930 standard is right for you. It establishes the core PCRs for creating external auditable reports (Environmental Product Declarations) for construction materials, which is exactly what you’d want to submit to your government buyer. You can use it with National Science Foundation’s Portland Cement PCR, which is focused on cement in North American markets.
- Are you a pet food manufacturer with a global customer base (and especially large market in Europe) looking to eco-label your kibble in the market?
- Try EU’s Product Environmental Footprint (PEF) standard. The complementary PEFCR (PEF Category Rules) for pet food are under revision (expired 31/12/2020); once these are revalidated, use them with PEF to enhance the consistency of your analysis with that of your peers.
- Are you a paper packaging manufacturer in the UK supplying customers with stringent data quality expectations?
- Try the British Standards Institution’s PAS 2050, last revised in 2011. It was originally developed for the UK economy (now recognized in the US, China, and Europe) and requires a third-party audit of all PCFs. Assuring your PCF through third-party verification will signal to your customers that your data is robustly prepared and ready for integration into their footprinting.
To get you started with methodology selection, try our decision tree below, adapted from Pre Sustainability and consistent with the PACT Methodology (guidance developed by the World Business Council for Sustainable Development to provide uniform instructions for when to use different methodology standards and guidelines, assumptions to make where these standards/guidelines are open-ended, and how to configure PCF reports for easier data-sharing).
Want to discuss your needs? Our Green Project experts can do a custom screening and recommend a path forward.
How Can Green Project Help?
The Green Project platform offers automatic data collection and a robust carbon accounting engine for accurately calculating Scope 1, 2, and 3 emissions at the activity level. Companies using our solutions are well-positioned to take on PCFs through a top-down approach, allocating activity data from company processes to one or more of their company’s products.
Our experts can get you started on this exercise today for products and services, including helping you share this data with your B2B customers by developing supplier-specific emission factors aligned with the GHGP Scope 3 Standard.
In 2025, we’ll also be launching a new emission factor builder: a simple, in-platform tool for suppliers to create and assign emission factors to customers on their own.
Companies seeking to conform with more rigorous standards such as ISO 14067 or PEF, or who’d like to add an eco-label to their products or publish an Environmental Product Declaration, will demand a higher level of data quality. We can help with that, too, with Green Project’s in-house advisory services and our strong network of relevant industry partners.
Reach out to learn more about our robust Product Carbon Footprint (PCF) solutions.