“Product Carbon Footprint”…”Life Cycle Assessment”…even these terms may seem like intimidating jargon, if you are new to this subject.

But the steps involved in calculating a Product Carbon Footprint are straightforward, even if some of the techniques required to do so are not.

Step 1: Define your Project Goal and Scope

A very careful definition of the goal of the project will facilitate the entire LCA and Product Carbon Footprinting process, saving you time and resources. You should answer these key questions:

Why do I want to complete a Product Carbon Footprint?
How will the Product Carbon Footprint be used?
What is the intended audience of the results?
Are you intending to compare the Product Carbon Footprint to another?
Is there a specific standard (e.g., ISO 14044, ISO 14067), I need to use, to meet the study goals?

Make sure to write these down, as they will serve as a “lodestone” to avoid scope creep and keep your priorities straight.

As part of the scope definition, you will also need to define whether the Product Carbon Footprint will be:

Cradle-to-grave, including all life cycle stages, from raw material extraction, through use and end of life. Depending on your end goal, these system boundaries may be required to satisfy the requirements of various standards; for example, if you are interested in a Product Carbon Neutral claim, you will need to include the full cradle-to-grave life cycle.
Cradle-to-gate, where the Product Carbon Footprint includes all life cycle stages from raw material extraction up until when the product leaves your factory. This type of Product Carbon Footprint may be necessary when a product can be used in a very large number of ways, such as precursor material resins which could be used in a variety of products, making it impossible to model the use and end of life phases.
Gate-to-gate, meaning that the LCA only includes the GHG emissions from the manufacturing facility itself, ignoring all Embedded GHG emissions and the full life cycle. These types of studies are used generally only when you are creating datasets to be used in larger, cradle-to-gate, or cradle-to-grave, Product Carbon Footprints, or when the dataset is to be used in a LCA database.

Perhaps the most important part of the scope is to define a functional unit, against which the Product Carbon Footprint results will be made relative. The functional unit can take several forms, including per mass of product, or for the use of the product over a given period of time. Since the LCA results are made relative to the functional unit, defining an appropriate functional unit is one of the most important steps in the entire process. Define a functional unit incorrectly, and your Product Carbon Footprint might not make sense.

Step 2: Gather LCA Data

Gathering Primary LCA Data

Now you must gather data from the manufacturing facility and any other parts of the supply chain which are involved in its production. If your company is a coffee mug producer, this would involve acquiring primary data on the cup molding or extrusion process. This data includes the amount of energy used to produce a product, the material inputs, and packaging materials used. At Nova Creatio Sustainability, we have a standard Data Request Form which we use to collect this data, but often, a tailored data request is required to gather data from across the whole supply chain.

Gathering Secondary Data by Mapping Precursors to LCA Data Sources

Perhaps the single part of the LCA study requiring the most experience is identifying secondary data to use for those life cycle stages where you don’t have primary data. For example, while you may have obtained data on the extrusion and molding of a coffee mug, this does not give you information on the embedded GHG emissions of the clay which is used to make the mugs. The production of this clay must be represented using “secondary” datasets, from public databases like ecoinvent or GaBi, or from published technical literature.

Step 3: LCA modeling

The modeling and calculation of the Product Carbon Footprint can be completed using a tool as simple as an Excel spreadsheet, or as complicated as a professional LCA software like SimaPro or openLCA. These softwares crunch the numbers for the GHG emissions occurring across the entire life cycle, into a single result.

A vital, yet often overlooked, part of a Product Carbon Footprint study, are the various checks necessary to ensure the quality of the output. Sensitivity analysis, contribution analysis, and data quality checks, are all important ways to review the LCA model outputs, ensuring their accuracy and validity.

Step 4: LCA report writing

Regardless of the end use of your Product Carbon Footprint, a technical report will be needed to describe the methodology and data sources used to calculate results. ISO 14044 refers to this report as a “third party report”, and ISO 14067 as a “Product Carbon Footprint Study Report.” These documents serve to underpin any claims you wish to make, and can serve as a reference in the future, or if you or anyone else need to review how a study was completed.

Step 5: Critical Review

In many cases, a critical review will be necessary to achieve your study goals. The level of depth of a critical review varies based on the desired application of the Product Carbon Footprint; most go through a review by a single other person, who can be a member of your company or an external reviewer. For certain types of LCA, a panel of experts may be needed.

Step 6: Claims preparation

Once the LCA report and the Product Carbon Footprint have been finalized, you now have what you need to finalize the claims language you wish to use.

Need help in evaluating a Product Carbon Footprint?

You can read our series of blog posts to learn more about Product Carbon Footprints, Life Cycle Assessments, what is required to create them. Or you can contact us directly if you need support, at info@novacreatio-sustainability.com or visit our Contact Us page.

How to Calculate a Product Carbon Footprint