Methodology of ecoinvent 3

Methodology of ecoinvent 3

Why is the amount of the reference product changing?

In the raw version of a dataset, the undefined UPR, the amount of reference product is not always 1. For example, the dataset “cotton production, CN” has a reference flow of 1000kg of cotton fibre. Additionally, an allocateable by-product, cotton seed, results from this activity.

 

 

 

 

Whenever the amount of the reference product is not 1 in the undefined UPR, it is scaled to 1 when a system models is applied. With that, also the amounts of all exchanges are scaled accordingly. However, it must be noted that the amounts of the other exchanges are not necessarily divided by 1000 as well. It can be seen from the table, that the production of 1000kg of cotton fibre result in carbon dioxide emissions of 335kg, while in the cut-off system model 1 kg of fluting medium is responsible for only 0.269 kg carbon dioxide. The reason is that this dataset has also produces a by-product. Hence, when applying a system model the exchanges are being allocated between the different reference/by-products according to the methodology of the respective system model.