Impact Assessment Method Flow Variations

Question

Hi all!

In completing an LCA project (for a wood product) in openLCA, I ran impact assessment methods for two versions of TRACI – one associated with Ecoinvent v3.3 and one associated with openLCA LCIA methods 1.5.6.  The results were drastically different, with the TRACI LCIA 1.5.6 results for GWP being almost 4 times greater than using Ecoinvent v3.3 TRACI.  After digging into the impact assessment methods impact factors, I saw that Ecoinvent TRACI only included 4 flows for carbon dioxide, with no biogenic flows.  The LCIA TRACI includes 30 flows for carbon dioxide, including biogenic carbon.  

I also saw similar differences in results/impact factors between the two CML (baseline) versions (Ecoinvent v3.3 and LCIA 1.5.6).  

I ended up using openLCA LCIA v1.5.6 since its flows were more comprehensive, however I would still like to know why the flows are different between LCIA v1.5.6 and ecoinvent 3.3 if the impact assessment method is the same (TRACI).  Has anyone else noticed this?

Thanks!
Amy

Answer 1

Hello Amy,
welcome and: yes, I think this is unfortunately a common topic. The ecoinvent methods that we distribute are directly from ecoinvent; some time ago we have started to develop an own LCIA method pack, reflecting other databases and thereby also other elementary flows, in part, but also to be able to update and modify methods.
Best wishes,
Andreas