Calculating Product Environmental Footprint (PEF) for companies in the chemicals industry can be particularly challenging. On average, more than one-third of a chemical company’s emissions lie in Scope 3, which are notoriously tricky to calculate.

Given chemical industry contributes 8% to global industrial greenhouse gas emissions, and most of these emissions are in the Scope 3 category 1 (3.1) “Purchased goods and services”, special attention needs to be paid to understand, measure and reduce emissions in this category through high quality PEF calculation.

There is a growing demand for clear, trustworthy product-level emissions data, which is driven by increasing demand from customers to accurately measure Scope 3 emissions. As many chemical companies are both a supplier and a manufacturer; the urgency for accurate product footprint calculation on their part is heightened.

PEF deep dive and system boundaries for chemical companies

At its core, the product environmental footprint measures the total greenhouse gas emissions associated with building, selling, using, and disposing of a product.

This comprehensive approach encompasses all stages of a product's life, including production, transportation, usage, and end-of-life processes, commonly categorized as:

• Materials
• Upstream transportation
• Production
• Distribution and storage
• Product use
• End-of-life, including disposing of the packaging

There are two main system boundaries to keep in mind:

• Cradle-to-gate: From when the components to make the product are produced to when the product arrives at the customer’s location (e.g. factory, shop, house).
• Cradle to grave: Counts all emissions until the product has been destroyed or recycled.

Methodology for calculating product footprints

There are established and commonly recognized guidelines within the industry, that need to be followed in PEF calculations. Commonly, these include the following:

ISO Standards:

• ISO 14064 -1: 2019
• ISO 14064 -2: 2019
• ISO 14064 -3: 2019
• ISO 14067: 2019
• ISO 14040: 2006
• ISO 14044: 2006

GHG Protocol Standards:

• GHG Protocol Corporate Value Chain (Scope 3).
• GHG Protocol Scope 3 Calculation Guidance.
• GHG Protocol Product Standard.

Steps to be followed in your PEF calculation

1. Define objectives and scope of calculation

The first step is to define what the PEF will measure. This includes identifying the product, its life cycle boundaries (from raw material extraction to factory gate), and relevant activities involved in its production. Clear system boundaries ensure consistency and comparability.

2. Gather data and build an Inventory

To calculate emissions, companies must collect activity data related to production processes, such as material inputs, purchased products, energy use, direct emissions etc. This data is essential for accurately assessing the environmental footprint at different stages of the supply chain.

3. Assess life cycle impacts

Once data is collected, emissions are calculated by multiplying activity data with appropriate emission factors (CO₂ equivalent per declared unit). This step also includes considering multi-output processes and allocating emissions accordingly.

4. Consolidate PEF Data

The PEF is finalized by summing up all GHG emissions from each stage of production. If production occurs across multiple sites, companies may need to perform sub-calculations and apply site-specific or secondary data. For communication purposes, aggregated values can be used, ensuring transparency in data quality.

5. Report and Update Regularly

PEF calculations should be documented and reported systematically. The data should be as recent as possible, ideally from the past five years, with updates performed regularly. Companies should review and recalculate PEFs if production processes change significantly or after a defined validity period (e.g., five years under EN 15804 +A2:2019).

By following these steps, businesses can accurately assess their product’s footprint and identify opportunities to reduce emissions, contributing to sustainability goals.

Here's a simplified version of the methodology for computing PEF:

1. List all of the ingredients, materials, and activities needed to produce one item such as BOM (Bill of Materials), site activities, supplier information, etc.
2. Multiply each of them by the most relevant emission factor associated with the activity.
3. Multiply the total emissions of one product by the number of units sold.

In reality, it’s much more complex to determine exactly which emissions are associated with which product or activity. It's important to document the methodology chosen to associate emission factors, so as to be able to compare products and analyze the evolution of a product across time.

For a more detailed guide on calculations, check out our guide on Scaling Product Environmental Footprints (PEFs).