Dear all,
I'm looking for the value of the economic allocation made for wood coproducts (wood chip, sawdust etc.). I can't find this information in Ecoinvent reports.
Thanks a lot
Pauline
Dear Pauline,
Thank you for your thread. In order to calculate the economic allocation for a product you need the price of the product (available in the linked UPR dataset), and the mass of it (available in the UPR dataset). You can check the methodology of how economic allocation is applied in the data quality guidelines. If you have issues with it, feel free to send us an email.
Best regards,
Avraam Symeonidis,
Data analyst, ecoinvent association
Thank you for the answer Avraam.I've looked at the UPR dataset of hardwood forestry, beech, sustainable forest management, DE (1m3) (https://v35.ecoquery.ecoinvent.org/Details/UPR/4fac7e8b-4d75-4b13-a362-e6f324749dbc/8b738ea0-f89e-4627-8679-433616064e82)and found the 4 wood coproducts:- cleft timber, measured as dry mass, 203,76 kg and a price of 0,073 €/kg- pulpwood, hardwood, measured as solid wood under bark, 0,3m3 with a density of 974,16 kg/m3 so 292,25 kg, and a price of 250€/kg- sawlog and veneer log, hardwood, measured as solid wood under bark, 0,26m3 with a density of 920,04 kg/m3 so 239,21 kg and a price of 85€/kg- and wood chips, wet, measured as dry mass, 60,86 kg and a price of 0,107 €/kg.
I've computed the economic allocation for instance for woodchips : 0,107/(0,073+250+85+0,107) = 0,0003 = 0,03%.
But I cannot find how it has been applied in the woodchips data. For instance there an input from technosphere for the four corpoduct of "Diesel, burned in building machine" :0,023 MJ for woodchips0,023 MJ for cleft timber13,86 MJ for pulpwood13,86 MJ for sawlog and veneer logso in total 27,76 MJ. If I multiply 27,76 by the computed economic allocation of woodchips, 0,0003 :27,76*0,0003 = 0,0089 MJ and not 0,023 MJ as mentionned in the data...
Can you explain me how is made this economic allocation and how I can get rid of it ? I've been searching (with colleagues) but I can't understand how it is made. You can find attached an excel with the calculation (and also one with input from nature Carbon dioxide, in air).Many thanks,
Pauline
Dear Pauline,
The answer is really simple. There is no economic allocation applied in the dataset you are reffering to. Allocation is applied when a "Reference product" is produced along with a "By product". In your case here the dataset is producing only "Reference products" which means that it is a combined production dataset. Subdivision of this dataset is taking place based on the mathematical formulas in each of the exchanges.
Best regards,
Avraam Symeonidis,
Data analyst, ecoinvent Association
I'm a bit lost. I'm ok on your answer saying that UPR dataset of hardwood forestry, beech, sustainable forest management, DE is the reference product of the wood chips which produces reference products too.
So I've just looked at the "wood chips production, softwood, at sawmill, CH" : the value in the UPR link and in the Pre-allocation link are the same, which would mean that there is no allocation at all made on woodchips ? Or I don't look at the right UPR ? I can't find wood chips under a by-product state.Howerver Guillaume Bourgault, Project Manager, ecoinvent, wrote on 10.03.2016 in the topic "Wood - Negative result (production and disposal)" the following answer: "The imbalance you observe is due to economic allocation. Wood-related activities often have many by-products, and the impact is allocated according to the price of each products and by-products. This creates a distortion of the mass balance in the allocated datasets, and this in turn causes imbalance when you look at the whole system."So there is an economic allocation...And further calculations :the table 1-3 "Total harvesting over one rotation period relative distribution in main assortments according to the harvesting in2011, un m3 solid under bark (sub) (own calculations based on Albrecht et al.,Anonymous 2012, Anonymous 2010 see attached file 1)" gives 44% of energy wood, of which 23% of wood chips which makes 10% of wood chips on the whole.Anf if we multiply this 10% by the inputs of the wood chips process, divided by the amount of woodchips produced (60,68 kg) mentionned in the "hardwood forestry, beech, sustainable forest management, DE" dataset, we get the right amount of the considered input ! please see file 2 attached excel to understant.Two questions then :- it looks like a massic allocation, and no economic, but it's not coherent with your above collegue explanation... was it a mistake ?- the data Sawlog and veneer log, hardwood, measured as solid wood under bark {DE}| hardwood forestry, beech, sustainable forest management seem to be the reference product giving the byproduct wood chips, am I right ? But woodchips come from energy wood, and not sawlogs (attached file 1)...
I hope I'm explanations / issues are clear !
Thanks !
Pauline
Dear Pauline,
1. "wood chips production, softwood, at sawmill, CH", no allocation here as this dataset does not produce a "Reference product" along with a "By product".
2. woodchips are produced by many datasets in the database. I cannot say if everywhere they are produced without allocation. Allocation is applied when a "Reference product" is produced along with a "By product".
3. What my colleague wrote, was and is still correct now as allocation is applied in the dataset he is reffering to, the one producing "Sawnwood, lath, softwood, dried (u=10%), planed".
4. In the dataset "hardwood forestry, beech, sustainable forest management" in DE, all products are Reference products. No by-products and no allocation taking place. The following are reference products produced by the aforementioned activity.
a) sawlog and veneer log, hardwood, measured as solid wood under bark [m3]//
b) pulpwood, hardwood, measured as solid wood under bark [m3]//
c) wood chips, wet, measured as dry mass [kg]// and
d) cleft timber, measured as dry mass [kg]
For anything else, please send us an email and plesae do not upload files with LCI or LCIA values. Thank you for your understanding.
Best regards,
Avraam Symeonidis,
Data analyst, ecoinvent Association
Thank you for your time and answers Avraam.Sorry for the publishing of these values (you may suppress them).Maybe Ecoinvent could specify not to give this kind of values next to the "Submit" button or somewhere on the Forum page, as a reminder ?
Best regards,
Pauline