Working with OpenLCA inputs and outputs (use additional information about a process than the quantitative reference)

Question

Ok, so I'm very new to openlca, but here's essentially what I'm trying to do:

1. I've got two processes "bus" and "car" defined. As inputs both of them take various materials such as steel, glass, plastic (in kilograms). The output of these processes is 1 bus and 1 car, respectively.

2. I have another process that described a particular order from a customer, which takes as input X "bus" and Y "car" objects. It also contains transportation by boat and by train of said buses and cars to the customer, defined as t*km (tonne-kilometers).

I want to use the total weight of the buses and cars to get the "tonne" part of my process. How can I do this? I could easily add a new output "total weight" into both the "bus" and "car" processes, but doesn't that go directly against what an output is supposed to represent?

Answer 1

Hello meklund,

I understand your train of thought, but this is not possible unfortunately. OpenLCA calculates a lot of information, but it does not transform one unit to another, and multiply it with a given distance.

If you really want this to be the case, you can build your system with global parameters.

Then you would have one parameter for the mass of each material, one that sums all the materials, and one for the distance traveled. When calling the parameters, you only need to multiply the distance with the sum of the mass.

Tbh this is not worth it unless you do large systems. I always do all my data transformation in a separate excel sheet, and then just input the numbers in OpenLCA.

Hope this answers your question, good luck.

Comments

Hi! Thank you for the clarification. The reason why I wanted to automatically calculate the tonnes*kilometer by train/boat for delivering the cars/buses to the customer is that I don't want to manually provide the full weight of the car, when the full weight can be calculate based on the individual material components that are given. These global parameters sounds like they way to do it, so that I don't have to provide "the same information twice".