The utility factor is calculated based on the expected longevity of the product compared to the average product life span in the industry. The longevity can either be defined by years in use or the amount of functional units (e.g. glow plugs have a longevity of about 60.000 km)
On a material basis, the expected lifespan of a material is compared to its category.
At the product level, the MCI assesses how long a product lasts compared to the industry average. In this context, the Linear Flow Index (LFI) will be calculated for each material used in the manufacture of the product. However, when assessing the Utility Factor and thus comparing the product’s lifetime to the industry average, the analysis will be conducted at the product level, not the material level.
At the material level, the MCI evaluates the durability of a material relative to its material group. For instance, the longevity of polyethylene (PE) is compared to the average longevity of all polymers. So for PE the expected Lifetime is 18 years, for Plastic in general it is 10 years. Therefore the Utility factor of PP would be 1,8=18/10. For this reason, the comparability of circularity between different materials of different category groups can be biased.
Remember the allocation topic from the Goal and Scope Definition?
As mentioned before, there are many methods to tackle the allocation situation.
The EU Parliament has established Product Environmental Footprint (PEF) regulations to provide a standardized approach for product environmental assessment.
Within the PEF framework, a specific method known as the Circular Footprint Formula (CFF) has been introduced. The CFF is designed to calculate the environmental footprint of recycled materials.
Let us walk you through this approach with an example:
When a plastic bottle undergoes recycling to produce a t-shirt using the recycled material, the emissions generated during the collection, cleaning, and processing stages (such as shredding and pelletizing to form new plastic granulate) are typically attributed to the End-of-Life phase of the plastic bottle.
But we can also argue that, since this recycled material serves as the raw material for the t-shirt, then the emissions of the recycling should be included in the material production for the new product.
As a result, the emissions associated with recycling may appear to be counted twice.
This underscores the necessity for proper allocation methods to distribute emissions between the two product systems accurately.
Similarly, the benefits derived from avoiding the use of virgin materials in t-shirt production should not solely be credited to the t-shirt itself; a portion of these credits is also allocated to the original product. This approach ensures that the preceding product receives recognition for its contribution to recycling efforts.
The CFF offers a specific allocation rule for recycling processes. Based on this rule, the burdens and credits are split between the virgin and recycled material based on specific allocation factors.
The CFF formula is divided into three parts:
Material: the emissions from the material input and material recycling are calculated. In the next step, the credit for the avoided material is also considered.
Energy: the emissions due to the energy recovery process are calculated. As the next step, the credit for the avoided primary energy source is taken into account.
Disposal: The emissions of the remaining waste and disposal are taken into account.
For cradle-to-gate studies, the formula is simplified. In this simplified approach, only the first part of the material part is relevant, as the end-of-life phase is not included in the calculations.
The CFF for cradle-to-gate studies considers the impact of the virgin material and the impact of the recycled material input. This includes emissions from the recycling process as well as allocated impacts from primary material production.
-> Now, the EF of 1.66 can be used as material EF for the PET that consists 80 % recycled and 20 % virgin material. It is a bit lower than the virgin material EF which is 2.05 in our example. Take care that depending on the material, different production processes need to be added.
Here is an interesting video to learn more about the CFF. Are you interested in learning more? Here are some helpful links:
| abbreviation | description |
|---|---|
R1
share of recycled material
EF virgin
emission factor of virgin material
EF recycled
emission factor of the recycling process
A
pre-determined allocation factor depending on the material
Q sin / Q out
pre-determined quality ratio determining the quality difference of the virgin and recycled material depending on the material
The Material Circularity Indicator (MCI) is calculated using the formula:
MCI = 1 - LFI*(0.9/Utility Function)
Here, the factor "0.9" represents the weight of the product's longevity (utility function) relative to its circular performance (LFI). This factor aligns with the framework established by the Ellen MacArthur Foundation.
The MCI ranges from 0 to 1, where lower values indicate a more circular production process. The formulas utilised at Yook adhere to the guidelines set by the Ellen MacArthur Foundation.
The Material Circulator Indicator (MCI) assesses the circular performance of a product or material through three key metrics: firstly, the proportion of circular materials used (such as recycled or reused content); secondly, the end-of-life outcomes (determining whether a product is recycled or disposed of in a landfill); and thirdly, the durability of the product or material.
Non-recoverable waste
In essence, the circular performance of a product or material is assessed by comparing the weight of non-recoverable waste generated during both production and end-of-life phases to the total weight of the product or material.
We start by categorizing the input materials as virgin, recycled, reused, or biological. This classification is essential for calculating the amount of non-recoverable waste generated during the production of a product.
Then, we examine the end-of-life scenarios, such as recycling, reusing, composting, or energy recovery. This information is crucial for determining the amount of non-recoverable waste produced after a product's lifecycle.
More information on the assessment of the circular performance will be provided in the section Linear Flow Index.
The other aspect of the MCI is the longevity of a product. Here the longevity of a product will be compared to the industry average.This metric compares a product's lifespan to the industry average, with longer-lasting products positively influencing the MCI score. It's important to note that the assessment of longevity differs when calculating the MCI for a product versus a material. Further details can be found in the deep dive section Utility Factor.
Yook's MCI calculator is based on the 2019 revision of the methodology by the Ellen MacArthur Foundation and GRANTA Design.
Information that need to be provided for the calculation:
the share of reused materials
the share of recycled materials
the share of sustainable biological materials
Product lifetime or number of functional units achieved during the lifetime
Information that can help increase the accuracy of the calculation:
collection rate for recycling [%]
Efficiency of recycling [%] (how much recycled output will be created)
rate of biological material meeting criteria for energy recovery [%]
efficiency energy recovery
rate of component reuse
Industry average lifetime or average number of functional units achieved during the lifetime
Advantages
Provides another indicator of sustainability alongside the Product Carbon Footprint (PCF)
Promotes the use of recycled or reused materials and encourages recycling at the end of the product's life
Considers longevity; thus, materials with higher durability compared to the industry average have a positive impact on MCI
Limitations
Methodology can be unclear in some instances
Lack of data for average product lifetime and recycling/collection rates due to limited adaption
Despite its limitations, the Material Circularity Indicator (MCI) is a valuable tool for considering circularity and durability alongside the Product Carbon Footprint (PCF) in material and product selection.
The Linear Flow Index (LFI) calculates the circular performance of a product or material by analyzing the share of reused, recycled, or sustainable biological feedstock as input and the recycled, reused, energy recovered or composted share at end-of-life as output. This helps understand how much unrecoverable waste the product creates in its lifetime in relation to its weight. The LFI ranges from 0 to 1, with 0 representing complete circularity and 1 representing complete linearity.
In recycling purposes, the calculation applies the "50:50 approach", meaning that it considers both the waste generated for the use of recycled materials (recycled feedstock) and the waste produced during the recycling process at the end-of-life stage. This is best explained using an example. Let's take two products (P1 and P2) with 50% recycled material. At the end of its life, P1 is recycled and has a recycling efficiency of 50%. This recycled material is used as the recycled feedstock for P2. If we were to take 100% of the waste generated from the use of recycled material into account, we would count the waste from the recycled material in P1 twice, because P2 is partly made of the materials of P1. One solution for this problem would be only taking into account recycling at end-of-life. As this would place unequal penalties at end of life stage in comparison to recycled feedstock, the 50:50 approach is applied. This provides equal emphasis on both recycling processes and a holistic perspective of the circular performance of a product.
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 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.
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.
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.
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: