Differences between LCIA method packs

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mseier
Posts: 4
Joined: 08 Apr 2015 16:02

Differences between LCIA method packs

Post by mseier » 08 Apr 2015 17:00

Hi,

I just downloaded the openLCA LCIA methods pack 1.5.4 (http://www.openlca.org/documents/14826/ ... fbbd857b7f). Up to now, I use the ecoinvent dataset from openLCA Nexus.

Comparing the LCIA results obtained from CML2001 (e.g. GWP100 / independently from using the baseline/non-baseline method) I remarked that biogenic CO2 has a characterization factor of 1. In the ecoinvent version of CML2001, CO2 is rated with a CF=0.

Was this implemented on purpose and if yes, for which reason?

Best wishes, thanks for the great work and support!
Max

aciroth
Posts: 750
Joined: 09 May 2010 23:28

Re: Differences between LCIA method packs

Post by aciroth » 08 Apr 2015 19:41

Hi Max,
yes this is on purpose although we are thinking of providing this as a parameter so that it can be modified by users; I would say this are just different thought-schools. Do you think this is interesting?
Best wishes,
Andreas

mseier
Posts: 4
Joined: 08 Apr 2015 16:02

Re: Differences between LCIA method packs

Post by mseier » 09 Apr 2015 10:50

Hi Andreas,

I am sure that this is at least worth a discussion because both, setting the factor to 0 or 1, in my opinion comes with a simplification.

For the specific LCIA methods pack I think that it is quite unfortunate because the documentation says that the methods pack is conform to the IPCC approach which rates the emissions as carbon neutral. Using the CML method from the ecoinvent and using CML from your methods pack should not lead to different results. It should be more transparent that biogenic CO2 is rated as equal to fossil CO2, because otherwise, only the choice of the methods pack has a large influence on LCIA results (especially talking about bioenergy which is my modeling scope). If a user just does a quick calculation of product systems without having a closer look at the LCI, this can lead to significant mistakes. Nevertheless, of course everything depends on the modelling of the pre-chains in the system and therefore the setting of system boundaries.

Best wishes
Max

aciroth
Posts: 750
Joined: 09 May 2010 23:28

Re: Differences between LCIA method packs

Post by aciroth » 09 Apr 2015 12:50

Hi Max,
I agree, and I also agree that setting a factor as 0 or 1 is a simplification. You probably are aware of Cherubini F, Peters GP, Berntsen T, Stromman AH, Hertwich E (2011) CO2
emissions from biomass combustion for bioenergy: atmospheric decay and contribution to global warming. GCB Bioenergy 3:413–426 which confirms exactly that. I am not getting
For the specific LCIA methods pack I think that it is quite unfortunate
- it is unfortunate that setting the factor to 0 or 1 is a simplification? That the method is called IPCC GWP but sets a factor of 1 and -1 and not 0? In CML, the flow biogenic CO2 does not exist, and we added it with the same CF as fossil CO2 which is a slight overestimation, but of course Carbon uptake is considered negatively, i.e. reducing GWP, and thus in a simplistic LCA model this should level out and become neutral.

This is all documented for openLCA here (http://www.openlca.org/lcia-methods):
2015-04-09 12_24_01-LCIA methods - openLCA.org.png
2015-04-09 12_24_01-LCIA methods - openLCA.org.png (21.92 KiB) Viewed 2832 times
2015-04-09 12_22_28-c548f249-4f66-46a7-93a2-b915b0e0eec6.png
2015-04-09 12_22_28-c548f249-4f66-46a7-93a2-b915b0e0eec6.png (15.92 KiB) Viewed 2832 times
And all the factors are here:

http://www.openlca.org/files/openlca/Up ... 1_5_4.xlsx

I agree we could maybe stress this our interpretation a bit more. And I would definitely like a discussion about the integration of LCIA methods with databases. At present, I honestly think you will always get different results depending on the LCIA method you choose; one plain reason is that e.g. the ecoinvent LCIA method pack uses a less recent CML release than we in our method pack from March 2015.

Best wishes,
Andreas

atjack
Posts: 17
Joined: 06 Jan 2015 15:39
Location: Berlin

Re: Differences between LCIA method packs

Post by atjack » 15 May 2015 14:21

Hey,

just as remake, maybe it's make sense to include a impact category with biogenic as 1 and one with 0, because it's also often make sense to compare this two scenario’s.

greetings

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