inputs and impacts from Processes created by me

Question

Dear all,

Prepare yourselves because this maybe be an obvious question for you but it is bothering me in a way that I do not know if I am making something that is simple very complex. So, I decided to share it with you all.

I am building a value chain (with several processes) where an output of the 1st process is the input of the 2nd process.

The 1st process uses an dataset from ecoinvent (cultivation of soybean). The following process is the extraction of oil from soybean. I know that there is an ecoinvent data set for it (soybean oil production).

If I make a process using as input the ecoinvent dataset for soybean cultivation, it will give me the LCIA impacts related to it. Imagine it is 10 kg CO2 eq./ kg of soybean seeds.

If I make another process using as input the ecoinvent dataset for soybean oil production, it will give me the LCIA impacts related to producing oil from soybeans. Imagine it is 25 kg CO2 eq./ kg of soybean oil. This LCIA result also consider the impacts from soybean cultivation, or only soybean oil production?

I ask this because my issue is related to the same situation but when I have to link the 1st process (soybean cultivation) to the 2nd process (soybean oil production). To do so, I have to put as input the output from the 1st Process and then as another input the ecoinvent dataset for soybean oil production? My objective is to be sure that the 2nd Process is using as one of its inputs the output of the 1st Process and not a new input.

Thank you for your thoughts.

Godspeed.

Answer 1

Hello,

for an understanding. If you build a product system to calculate the impacts, you will select a reference product (soybean oil) with a quantity (1 kg) from the process of interest (soybean oil production). If you then have a look in your model graph, you will see that the whole supply chain is connected. Hence, the impacts for the full supply chain are given later on in your impact analysis. So, to answer. Yes, in your 2nd process, the inventory of the 1st process is included so are the impacts. Have a look in the model graph, it will explain everything (as long as you are using the unit process version of ecoinvent). The same goes for the impacts, where the Sankey diagram or the Contribution Tree will help you to understand where your impacts derive from.

I can highly recommend having a look at the manual, the YouTube channel or taking a basic training class.

Hope this helps