Delivering on the Transparency of the Product Carbon Footprint of Engineering Plastics

The Product Carbon Footprint (PCF) has fast become an essential indicator of the climate impact and resource efficiency of products in the supply chain of engineering polymers. Although the raw materials consumed in production account for the highest share in the figures, the energy mix used in the manufacturing processes can have a significant influence on the effective PCF values. Envalior has identified key differences in regional market conditions, such as the predominant use of coal-based electricity in caprolactam and PA6 production in China, which is often masked when relying on generic and outdated databases.

As a result, the company has decided to apply a PCF calculation approach based on local supply conditions, providing a more transparent decision-making basis for customers who seek to boost the sustainability of their end products. The updated figures obtained by the approach clearly demonstrate the positive impact of efforts taken by European caprolactam and PA6 manufacturers to minimize the greenhouse gas (GHG) emissions and improve the abatement of nitrous oxide (N2O) in their operations. (Figs. 1 & 2)

Figures 1 & 2: Comparison of PCF figures for caprolactam and PA6 calculated by applying a local-to-local approach in compliance with IPCC 2021, including external data from specific raw material suppliers and international consultancies (Graphics © Envalior)

Transparent Calculation Approach

The new approach complies with the principles for PCF quantifying and reporting according to the Life Cycle Assessment (LCA) standards as specified in ISO 14040 and ISO 14044, and follows the guideline of the World Business Council for Sustainable Development (WBCSD) on Life Cycle Metrics for Chemical Products.

According to these requirements, the PCF – or more generally the Global Warming Potential (GWP) – is quantified in a manner consistent with a methodology developed by the United Nations Intergovernmental Panel on Climate Change and adopted in 2021 (IPCC 2021), which covers more than 200 substances including CO2, N2O and methane. The calculated emissions are expressed as kg CO2 equivalents per kilogram of product (kg CO2eq/kg).

Notwithstanding the transparency provided by these procedures, none of the resulting PCFs is an industry standard. Instead, they can vary considerably, depending not only on the specific engineering plastic but also on the raw materials sourced from different local suppliers and on the type of energy used in production. The database values must therefore be kept up-to-date, including all Scope emissions.

Emissions by Scope

Under the GHG Protocol, Scope emissions are divided in direct and indirect emission categories. Scope 1 refers to direct emissions from in-house production processes, Scope 2 to indirect emissions from purchased energy, and Scope 3 to all other indirect emissions from upstream and downstream sources, such as material supplies, packaging and transportation. Since 2025, all companies subject to the Corporate Social Responsibility Directive (CSRD) must also measure and report their Scope 3 emissions.

Figure 3: Across the manufacturing value chain of engineering plastics, Scope 3 emissions contribute to 80% of the PCF values, indicating major opportunities for reduction by using lower-carbon raw materials. (Image © Envalior)

Since 80% of the PCF of any engineering plastic originates within the Scope 3 category (Fig. 3), lower-carbon solutions from upstream raw material suppliers are the most transparent route to a more sustainable value chain. For caprolactam and PA6 materials manufactured in Europe, the PCF figures obtained in Envalior’s fully compliant approach are much lower due to the increased use of renewable energy and the higher N2O abatement levels in comparison to Chinese operations, which still rely heavily on coal-based electricity and a lesser developed N2O management (Figs. 4 & 5).

Figure 4 & 5: Breakdown of PCF reductions achieved under current manufacturing conditions: The predominant use of coal-based electricity and less effective N2O abatement account for significantly higher PCFs for caprolactam produced in China. (Graphics © Envalior)

It should be noted that while Envalior’s PCF of 3.5 kg CO2 eq/kg for PA6 is considered the lowest in Europe, the higher 11.7 kg CO2 eq/kg value is still quite acceptable for PA6 produced in China. In both regions, the company is working towards further improving the PCFs of its products by reducing GHG emissions in its own operations, and/or by collaborating with its raw material suppliers to reduce theirs. In the future, sometime after 2030, PCF values of 2.0 kg CO2 eq/kg for caprolactam and PA6 seem possible in Europe.

Other opportunities for PCF reductions are offered by the increased use of mass-balanced circular and/or renewable feedstock, including additives and reinforcement fibers, in the production of PA6.

Market Fairness & Policy Gaps

However, various other players in the global caprolactam and PA6 market do not calculate their PCFs in compatible ways. And regional differences have resulted in an apparent price disparity to the disadvantage of European manufacturers, who are thus penalized for investing in greater sustainability. With cheaper coal-based electricity and lower N2O abatement, Chinese imports are clearly undercutting European producers who bear significantly higher sustainability costs.

Image I: Envalior’s N2O abatement plant in Antwerp helps the company reduce emissions by 400,000 tons of CO2 eq per year. (Photo © Envalior)

Although Envalior is firmly committed to maintaining its caprolactam site in Antwerp (Image I), the market is at risk of drifting apart, with Europe’s caprolactam production currently dropping below 20% of the global share. There is genuine concern that the unfair trade landscape could irreparably harm the European industry. Unfortunately, initiatives such as the Carbon Border Adjustment Mechanism (CBAM) and the Emission Trading System (ETS) of the European Union – both meant to put a fair price on carbon emissions from carbon-intensive products – are either not yet fully in force or not correcting the disparity with the required raw materials coverage and urgency, leaving European manufacturers of engineering plastics vulnerable.

Imposing higher tariffs on Chinese imports – as in the United States, where PCFs of caprolactam and PA6 are within the range of those in Europe – may seem like an easy solution, but would likely lead to retaliation, trade fragmentation and further market complications. A better instrument to remedy the competitive distortion is seen in local content requirements, e.g. higher rates of upstream materials to be sourced from European production, as well as in the use of harmonized PCF assessment methods and databases. Table I illustrates the wide discrepancy of current figures for caprolactam and PA6 in the field.

Table I: Product Carbon Footprint (kg CO2 eq/kg) data in need of harmonization

Outlook

PCF calculations using globally standardized principles and guidelines based on ISO 14040/14044 and IPCC 2021 provide comparable and transparent results, which is key for end customers in the plastics economy as well as for fair competition in the industry. Moreover, European manufacturers of engineering plastics investing in the increased use of renewable electricity and other effective environmental practices, such as N2O abatement, need better support by regulatory policy measures, including Carbon Border Adjustment Mechanism (CBAM) and local content requirements, to correct price and market distortions caused by Chinese imports produced under less sustainable conditions.

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