♻️Circularity

The relation between circularity and LCA

Circularity in LCA? Well, strictly speaking, circularity is not really part of an LCA, except when applying the CFF to allocate credits and burdens of recycling materials. Nevertheless, the circularity of a product is considered to be just as important as its environmental impact and even if it's not part of a traditional LCA, circularity can be calculated independently. However, quantifying products' circularity is not as straightforward as quantifying products' environmental impact: There exist around 300 circularity indices, but none of them has really established itself yet. One of the most recognized ones is the Material Circularity Indicator (MCI).

• There are two approaches for combining LCA and circular economy: by integrating circularity into LCA by using the CFF and by calculating an independent, additional metric to assess the product's circularity.

In the next two sub-pages we discuss the CFF and the MCI in more detail.

The circular footprint formula (CFF)

The European Commission introduced the Circular Footprint Formula (CFF) as part of the Product Environmental Footprint (PEF) assessment methodology to harmonize and standardize the analysis practices of recycling in LCA. It defines rules to allocate environmental burdens and credits for recycling, reusing, or energy recovering between supplier and user of recycled materials. Like this, emissions from recycling are not only accounted for in the End-of-Life phase of the first product but partly attributed to the subsequent product made with the recycled material. In the same way credits from the avoided virgin material are shared between the two product systems.

Material Circularity Index (MCI)

In addition to the Circular Footprint Formula (CFF), Circularity Indicators offer another method for evaluating the circularity of a product. Unlike the CFF, these indicators operate independently of LCA calculations and provide a distinct way to quantify a product's circularity. One notable indicator is the Material Circularity Index (MCI), developed by the McArthur Foundation.

In contrast to LCA-based approaches, the MCI does not involve the calculation of emissions, eliminating the need for the distribution of credits and burdens across multiple product systems. The MCI focuses on the analyzed product, assessing circularity aspects of material flows from raw materials to the end-of-life phase. The index calculates a circularity factor based on the proportion of recycled, reused, or sustainably produced biological material input and unrecoverable waste output generated at the end-of-life. Additionally, the specific product's longevity is a crucial factor in the calculations.

The importance of circularity and the limitations of LCA

Next to its inherent challenges of complexity and uncertainty, LCA is often critizied for not being a sufficient tool for informed decision making since it is not fully comprehensive.

Taking again a look at the wool example. Depeding on assumptions (allocation) and information about sheep husbandry, LCA results for wool can vary widely. But, in general, the cardle-to-gate-CO2e emissions of 1 kg knitted wool fabric are 10 - 100 x higher compared to a woven, mixed synthetic fabric.

Replacing wool by the synthetic fabric to save carbon emissions could nevertheless be an unfavorable decision:
  1. Use and EOL are excluded - and so are factors such as longetivity, which are an    important layer for decision making.
  2. The pure wool fabric is 100 % recyclable, while the mixed polyester fabric cannot be recycled.

This is why we calculate the MCI as additional indicator for the environmental and circular performance of a product. Find more about the calculation details in the following sub-chapters.

Interested in reading more? The following links may be helpful:

• https://pre-sustainability.com/articles/the-circular-economy-and-lca-make-each-other-stronger/

• https://www.sciencedirect.com/science/article/pii/S0048969723052361?via%3Dihub