Plastics are commonly used to produce many products, making it essential to understand how to model them in life cycle assessments (LCAs).
This article covers the essential steps of modeling plastic materials and components using ecoinvent datasets.
Don't feel like reading an article? Watch a video tutorial on this topic instead!
Feel like you're missing information? This article builds upon the following articles, check them out if you want to learn more:
On adding impact in Mobius: Mobius - How to: Add impact to your model using datasets
On adding impact in Helix: Helix- How to: Company level inputs
On environmental databases: Explained: Environmental databases in Helix and Mobius
On ecoinvent datasets: Explained: Ecoinvent datasets
On materials with multiple datasets: How to: Model materials with multiple datasets
Step 1: Determine the type of plastic in your product.
Before modeling plastics, consider the form you're purchasing plastic in. Companies usually purchase either plastic granulate (the ‘raw’ ingredient) or processed components made of plastic.
Is it a raw material? If your company purchases plastic as a raw material (e.g., granulate or resin), you only need one ecoinvent dataset to attribute impact.
Note - Examples of raw materials: Examples of primary, virgin granulates (the raw material) include:
Polypropylene (PP)
High-density polyethylene (HDPE)
Acrylonitrile-butadiene-styrene (ABS)
Polycarbonate (PC)
Amorphous Polyethylene-terephthalate (PET)
Recycled PET (RPET)
Is it processed plastic? If your purchased plastic is processed into a film, component, or finished product, you need multiple datasets to model the raw material (the granulate) and the processing separately (transformation from the granulate to a final plastic component). For more information on modeling materials with multiple datasets, read this article.
If you’re using processed plastics, you must find out how they were processed to become the purchased component. Step 1a outlines this process. Typical processes applied to plastics include extrusion, (injection) molding, or foaming.
[When applicable] Step 1a: Determine the plastic processing method used.
There may be multiple processing methods that produce the same material (e.g., plastic film is produced via extrusion or blow molding), making it more complicated to determine the one used in your case.
To solve this challenge, we recommend considering how much the plastic component impacts the total environmental footprint of your final product.
Small impact: If you expect the impact to be minimal (e.g., you’re modeling a few grams of plastic), it is likely sufficient to estimate the production process. Use online search methods to aid in your estimation.
Large impact: If the processed plastic component comprises a large part of your final product, spend more time determining the proper processing method used. Contact suppliers for information on plastic production methods.
Note - Examples of plastic processing methods: Examples of plastic processing methods include:
Extrusion
Injection molding
Foaming
(Stretch) Blow molding
…
Once the type of plastic and process are determined, such that you know how many datasets are involved, you can proceed to the next step.
Step 2: Find the material and/or process in ecoinvent.
Use ecoinvent to add impact to the plastic components in your model, incorporating raw materials and their processing methods separately. Start by adding impact for the raw material plastic, then repeat the steps for its respective processing method. Use the following steps as a guide:
Start by filtering for the database version used elsewhere in your model (e.g., ecoinvent v3.8).
Search for the material in ecoinvent using its full name. Plastics are listed by their full names rather than abbreviations.
Pro tip - Searching for materials in ecoinvent: If you're unsure about the full name of the plastic, you can search online or consult external resources.
Optionally (if using Mobius), ensure the unit used in your Product’s inventory matches the dataset units and properties. If these units differ, and you’d like to keep the unit of your choice, use the Properties in the Detail panel to tell Mobius the conversion between your unit and ecoinvent’s unit.
When applicable, repeat these steps for the material’s production method.
Steps 2a and 2b below provide examples of ecoinvent datasets for raw material plastics and plastic processing, respectively.
Step 2a: Find raw material datasets.
See Table 1 for examples of ecoinvent datasets for primary, virgin granulates (the raw material).
Table 1: Ecoinvent datasets for granulates.
Raw Material | Ecoinvent Dataset |
Polypropylene (PP) | polypropylene production, granulate | polypropylene, granulate | Cutoff, U |
High density polyethylene (HDPE) | polyethylene production, high density, granulate | polyethylene, high density, granulate | Cutoff, U |
Recycled HDPE | polyethylene production, high density, granulate, recycled | polyethylene, high density, granulate, recycled | Cutoff, U |
Low density polyethylene (LDPE) | polyethylene production, low density, granulate | polyethylene, low density, granulate | Cutoff, U |
Aacrylonitrile-butadiene-styrene (ABS) | acrylonitrile-butadiene-styrene copolymer production | acrylonitrile-butadiene-styrene copolymer | Cutoff, U |
Polycarbonate (PC) | polycarbonate production | polycarbonate | Cutoff, U |
Amorphous Polyethylene-terephthalate (PET) | polyethylene terephthalate production, granulate, amorphous | polyethylene terephthalate, granulate, amorphous | Cutoff, U |
Recycled PET (RPET) | polyethylene terephthalate production, granulate, amorphous, recycled | polyethylene terephthalate, granulate, amorphous, recycled | Cutoff, U |
Note - Dataset selection: All datasets listed in Table 1 exist as ‘production’ and ‘market for’ datasets. Similarly, these datasets are available for several regions (Europe, Rest-of-World, or Global). Consider this when deciding on which dataset to make use of.
Caution- Recycled plastics: Ecoinvent has many datasets available for primary, virgin plastic granulates. However, ecoinvent has a limited selection of recycled plastic (granulates) datasets. Contact the Ecochain Helpdesk if you’re determining the environmental impact of recycled plastic. Our environmental specialists can help you!
It is also important to consider, that as a company purchasing plastic granulates, you still must model the process of transforming the granulate into an intermediate product, just like companies that purchase processed plastics. You can do so in the following ways:
Model the process like companies that purchase processed plastics, by using predefined ecoinvent datasets
Model the process using your company’s primary energy data.
Step 2b: Find processing datasets.
See Table 2 for examples of ecoinvent datasets for plastic processing methods. Keep in mind that similar notes and cautions (Section 2a) apply to plastic processing methods as they do for raw material plastics.
Table 2: Exoinvent datasets for plastic processing methods.
Processing method | Ecoinvent Dataset |
Extrusion | extrusion, plastic film | extrusion, plastic film | Cutoff, U |
Injection molding | injection moulding | injection moulding | Cutoff, U |
Foaming | polymer foaming | polymer foaming | Cutoff, U |
Blow molding | blow moulding | blow moulding | Cutoff, U |
Video Tutorial
Watch these concepts explained in our Mobius software:
Next Steps
Modeling plastics using ecoinvent datasets is essential for conducting accurate life cycle assessments. This article provides a systematic approach to help you navigate the process. For further assistance, consider exploring additional resources on our help center or contacting us directly. Good luck with your LCA endeavors!
Can’t find a specific plastic, or plastic process? Let us know, by reaching out to the Ecochain Helpdesk!