This article explains the process of modeling materials using multiple environmental impact datasets from ecoinvent. This method is crucial for accurately representing materials, especially those that undergo various processing methods.
This article covers the essential steps of modeling materials with multiple datasets and provides concrete examples of this process in Mobius.
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
Step 1: Identify the processes involved in creating the material.
Every material is produced by a supply chain with different processes.
Some of these processes are more straightforward, meaning the same process (or set of processes) results in the same product. For example, grain is harvested, cleaned, …, and baked before it becomes bread. These materials can be modeled using one dataset that captures this typical process (Step 2).
However, some materials are processed in multiple ways. For example, plastics can be injection molded, extruded, etc, or steel can be rolled, cast, etc. Ecoinvent, therefore, offers datasets that capture different material processing methods separately from the unprocessed materials. These materials are modeled using two datasets - one for unprocessed materials and one for processing. In other words, multiple datasets are used to capture the impact of one material.
Note - Examples of materials that always require multiple datasets: Materials that are processed in multiple ways always require at least two datasets to capture the environmental impacts of the raw material and its processing. Some examples include:
Metals + process
Plastics + process
…
Try to identify the processes involved in creating the material in your model. Use internet searches or contact suppliers to determine how it is produced/ processed. This step can be tedious, and it is sometimes more valuable/ efficient to continue to the next step to aid in your identification.
Step 2: Search for and add the appropriate datasets in ecoinvent.
1. Search for the material name: Search for the full name of the material in the ecoinvent database.
2. Identify dataset type: Determine if the dataset includes only a process or the complete material production. Identify this by looking at the product listed in the dataset name (second part of the name).
Process only: If the dataset is a process, it doesn't include the raw material (Figure 1). These datasets require additional datasets to model the material. If you’re uncertain, check the dataset’s additional information to determine what inputs are included in the dataset you are considering.
Figure 1: Process-only datasets in ecoinvent.
Unprocessed material only: Similarly, to process only datasets. Some datasets exist that only contain the unprocessed material and no processing (Figure 2). These datasets typically require additional datasets to model the purchased intermediate product.
Figure 2: Unprocessed material-only datasets in ecoinvent.
Note - Combination of process-only and unprocessed material-only datasets: On their own, datasets that contain only the environmental impact of unprocessed materials or only the environmental impact of material processing are not enough to sufficiently model your material. They must be combined. For example, low-alloyed steel (Figure 2) with the hot rolling process (Figure 1).
Complete material: If the product includes the material name, it encompasses the entire production process (Figure 3). These datasets do not require additional datasets to model the intermediate product that your company uses.
Figure 3: Complete material datasets in ecoinvent.
3. If your material requires multiple datasets, combine them as follows:
Unprocessed material dataset: Find and add the dataset for the raw material (e.g., Figure 2).
Processing dataset: Find and add the dataset for the processing method (e.g., Figure 1).
Caution - Dataset compatibility: Ensure that the datasets are compatible and correctly represent the material and process. Check that:
The units of measurement match.
The properties align with your model requirements.
Examples in Mobius
In Mobius, you can add as many subitems to represent all the components of your material. Below are two examples - a screw and a composite plastic sheet.
Example 1 - Screw
If you’re modeling a screw, you need at least two datasets - one for the material itself (stainless steel), and one for the process. In this example, we use a generic metal working dataset to represent the process. However, if you know the exact processing method or the energy usage of the machines, those should be used as approximations. Figure 4 demonstrates the structure of an intermediate product consisting of at least 2 datasets.
Figure 4: Modeling a screw with multiple datasets in Mobius.
Example 2 - Composite plastic sheet
Suppose you have a composite material that consists of multiple inputs - for instance, a plastic sheet containing aluminum. On a high level, we know that composite material consists of the following materials: Polyester, Aluminium, Nylon, and some Polyethylene. These materials go through an extrusion process to make the sheet. Ideally, you’d know the exact percent distribution of the unique materials to model the inputs in the correct ratios. However, if you can’t determine this, you may assume an equal distribution of all materials for the first iteration of your LCA model. When you have multiple inputs going through the same process, it can help to cluster them together (Figure 5), meaning all the materials are grouped as subitems of the object ‘Plastic sheet materials’.
Figure 4: Modeling a composite plastic sheet in Mobius.
Video Tutorial
Watch these concepts explained in our Mobius software:
Next Steps
Modeling materials with multiple datasets is essential for accurate LCAs. By following these steps, you ensure that your materials are represented correctly, capturing the full environmental impact from raw material to the final product.
Good luck with your modeling in Mobius, and remember that practice and systematic approaches will improve your proficiency over time!
Can’t seem to find the right datasets for your model? Let us know, by reaching out to the Ecochain Helpdesk!