Contribution tree not adding up to 100%

Question

Hi, 

I wonder if any of you can help a novice like me. It is my understanding that the contribution tree will show the percentage contributions of impacts for all the processes. Am I right in assuming that it should always add up to 100%? If you add up all the processes it seems to sum up to 93.93 % only. What happened to the 6.07%?

Below you can see the contribution tree (Figure 1) and the model graph of my product system (Figure 2). Can someone shed light on this matter? 

     Figure 1. Contribution tree

       Figure 2. Model Graph

I will appreciate any help you can give me. 

Many Thanks!

Giancarlo

Answer 1

Hi Giancarlo,

the direct emissions from your pyrolysis process are not shown in detail in the contribution tree but are part of the 100 %. This micht explain your missing 6 %.

Regards,

Christina