ecoinvent Forum Archive

Hello,

i am currently working on an LCA for a wooden framed building. For that, the carbon uptake and gross calorific value stored in the wood are of interest. But for example in the dataset "glued laminated timber production, for outdoor use" the carbon uptake differs very much from the carbon content of the product (presumably due to the allocation made to create the dataset). According to the corresponding report ("Life Cycle Inventories for Wood as Fuel and Construction material, 2007) and another thread of this forum (https://www.ecoinvent.org/support/ecoinvent-forum/topic.html?&tid=191), allocation correction is supposed to solve the matter. Apparently allocation correction should have been implemented in ecoinvent 3.4 but did that happen ? I could not find it in the reports of the latest versions.

Thanks in advance

Christian

Dear Christian,

Yes, it is true that allocation correction was not implemented. However, for version 3.7 we just finished the implementation of carbon corrections for the wood and paper sector, which will be published later this year. We apologize for the misinformation in the mentioned thread.

Best regards,

Johannes Müller, Junior Data Analyst, ecoinvent association

Hello,I am also interested in these questions about allocation corrections. In version 3.7 only the wood and paper sector will benefit from these corrections or all sectors?

Best regards

Thibault

Dear Thibault, In 3.7 only the wood and sector section will be corrected in terms of biogenic carbon balance, which forms the base for future allocation corrections.Best regards, Johannes Müller, Junior Data Analyst, ecoinvent association

Dear Johannes,

I have difficulties finding the allocation correction in ecoinvent v3.7. I would appreciate if you could point me to where this correction is performed.

Thank you very much in advance and

kind regards

Rolf

Dear Rolf,

The adjustments in carbon balance for upcoming biogenic carbon allocation corrections are documented in section 4.5 of the report of changes for version 3.7.1 (https://www.ecoinvent.org/files/change_report_v3_7_1_20201217.pdf). Properties are accessible through ecoQuery, for changes implemented within the inventory you might also consider using the change report annex if you would like to see the specific changes introduced for the different datasets mentioned in the report. The annex is available on ecoQuery in the files section, supporting documents, file “ecoinvent 3.7.1_Change Report_including Annex.zip.7z”.

Best regards,

Johannes Müller, Data Analyst, ecoinvent association

Dear Johannes,

thanks for this explanation. I read the changes report Chapter 4.5. Unfortunately it does not contain data nor an example to explain the adjustments done.

So I cross-checked biogenic (non fossil) carbon of a dataset ("sawnwood production, hardwood, dried (u=10%), planed/Europe without CH"). This is my finding (carbon in product plus carbon emissions to air minus carbon extracted from air should balance):

+ Carbon (non-fossil) content: 321.1 kg (= 1'177 kg CO2 non fossil)

+ CO2 non fossil emitted to air: 192 kg (cradle to gate, LCI)

- CO2 in air: 2'226.8 kg (cradle to gate)

Total balance: - 858 kg CO2 non fossil

Do I miss some substantial non fossil carbon flows? If not, why does the non fossil carbon balance not result in net '0'?

Thank you for your time and answer

Rolf

one addition:

the non fossil carbon balance of hardwood shavings (10%)/Europe shows the opposite: net balance of non fossil CO2: +1.08kg per kg shavings (by-product of sawn hardwood). I.e. the amount of carbon fixed from the air is lower than the carbon in the product plus the carbon emissions to air.

Dear Rolf,

The changes applied in version 3.7.1 form the basis for upcoming allocation corrections and are not the allocation corrections themselves. In summary, the applied changes serve to balance wood and paper related datasets on the UPR level in terms of biogenic carbon. This is a perquisite for calculating the distortion introduced through allocation for each dataset as we do not want to correct for carbon which is simply present due to imbalanced datasets. The actual correcting flows will be included in the next version of ecoinvent.

I hope this clears things up.

Best regards,

Johannes Müller, Data Analyst, ecoinvent association

Dear Johannes,

thanks a lot for the clarification. In summary:

- allocation correction is NOT implemented in v3.7.1

- allocation correction is expected to be implemented in the upcoming v3.8.

- the -1/+1 approach required for biogenic Carbon by EN 15804+A2 leads to imbalanced GHG emissions in cradle to grave LCIs of materials based on wood and other renewable feedstocks when using v3.7.1 and previous versions.

Please correct me in case I misinterpreted your answer.

Kind regards

Rolf

Dear Rolf,

• Allocation correction is not in 3.7.1 – Correct.
• Allocation correction is expected to be implemented in the upcoming v3.8. – Specification needed: Allocation correction for biogenic carbon in the wood and paper sector is expected to be implemented in the upcoming v3.8.
• For your information, we will publish an “EN15804 version” of the Cut-off system model with the allocation corrections and the required EF3 method included.

Best regards,

Johannes Müller, Data Analyst, ecoinvent association