In order to model the incineration of a plastic that is not in OpenLCA, you need to know the Life Cycle Inventory of that process, this can sometimes be found in research articles.
However, with the given case, incineration of all four plastic types are available in EcoInvent. You need to:
1. Make a process with a reference flow. This flow is not important in this case.
2. Add four outputs into the process, under the input/output tab in the process:
2.a Waste polyethylene
2.b Waste polyethylene terephthalate
2.c Waste polypropylene
2.d Waste polystyrene
3. Choose the provider for each process to be incineration. It is important that you choose similar processes if you want to compare the processes. The process called treatment of waste PLASTIC TYPE, municipal incineration | waste PLASTIC TYPE | Cutoff, S - CH is available for all of them.
4. Go to the overview of the process, and create a product system. Click finish to the pop-up.
5. Click calculate, and choose an appropriate LCIA method. If you are in doubt, CML-IA, ReCiPe 2016, or EF 3.0 or EF 3.1 are all generally recognized. The LCIA determines which impact categories are included in the analysis. Once you have chosen, click finish.
6. Interpret the results that appear. Which plastic has the highest GWP when incinerated?