Differing results between openLCA and ecoinvent methods (CML2001)

Question

Hi, I am very new to conducting LCAs and I would very much appreciate your help! My study looks into biowaste management options (incineration, anaerobic codigestion), and I am using the latest Ecoinvent (v 3.4) dataset in openLCA 1.7. 

I am using the dataset "treatment of biowaste, municipal incineration|biowaste|Cutoff, U" but I obtain very different results when I do a CML2001 impact analysis. Under Ecoinvent 3.4 LCIA methods, I get 0.040kgCO2eq/kg of biowaste for GWP100a. However, when I use OpenLCA methods, I get a very different result of 0.556kg Co2eq/ kg of biowaste. Is there a reason why there is such a difference and which one should I use?

Thank you very much! 

Answer 1

Hi Natalie, the openLCA LCIA methods are customised for use in openLCA which may not be the case for the readily shipped LCIA method that comes with ecoinvent. As a result, the ecoinvent LCIA method possibly disregards some of the flows that are used in openLCA, - hence the low results. You can check this by opening the method in the navigation window. At the bottom you should find a tab impact factors which lists all the flows that are considered in the respective impact category. Either the ecoinvent LCIA method does not capture as many flows as the openLCA CML baseline method or it captures flows that are not used in the database (check via usage when right click on a flow in the navigation window of openLCA).

We always recommend use of the native openLCA LCIA methods.