Forum for ecoinvent Version 3

consequential model = attributional model ?

Written on: 16.06.2017#1

I compared the consequential and the average models by comparing the Chinese electricity mix represented in the consequential (substitution, consequential, long-term) and in the attributional (allocation, cut-off by classification) models. To my surprise the two mixes are identical, i.e. showing the same shares of power plant productions per kWh electricity. Even the market volume of the reference product is the same.

I would expect that the long-term consequential electricity mix of countries like China would look substantially different from the actual average mix today.

I then checked further countries like US, FR and CH with the same result: the consequential mix equals the average mix.

And also the consequential and the attributional unit process data of the production of Diesel in a European refinery and of the global petroleum market are identical.

It seems as if substantial parts of the consequential model are in reality duplicates of the attributional model.

Can you confirm this or highlight the datasets/markets with major differences?

Thank you very much in advance.

Written on: 20.06.2017#2

When comparing the datasets and discovering their similarity I was comparing the cut-off model with the APOS model (and not the "substitution" model).

So my questions are obsolete. The thread may be deleted.

Written on: 21.06.2017#3

Dear Rolf,

In this paper we have compared the 3 system models one to another, as well as cut-off against v2:

Steubing B., Wernet G., Reinhard J., Bauer C., Moreno Ruiz E. (2016) The ecoinvent database version 3 (part II): analyzing LCA results and comparison to version 2. International Journal of Life Cycle Assessment. September 2016, Volume 21, Issue 9, pp 1269–1281. DOI: 10.1007/s11367-016-1109-6.

Best regards,

Emilia

Written on: 22.06.2017#4

Dear Emiila,

thank you very much for the hint to the paper, which I am aware of.

The authors assess the number of datasets and their relative deviation comparing the LCIA results of consequential and attributional datasets available in ecoinvent v3.1. This is one way to look at it.

Similarly important is a comparison of the datasets on the unit process level. Indeed many of the consequential market and transformation activities are identical or nearly identica. For instance, most of the electricity markets show the same technology mix as reported by Christian Bauer in his talk page info "Electricity markets in different system models of the ecoinvent v3 database" available here. The same is true for the global petroleum market dataset, which shows the identical shares of proveniences as well as production technologies (no increased share of enhanced oil recovery, for instance). I would expect much larger differences between the consequential and the attributional models as shows a case study for the Swiss electiricty mix presented at the 62nd LCA forum.

In ecoinvent v3, the performance of the European petroleum refinery in terms of fuel input and emissions per ton of crude oil processed is the same in the consequential and attributional datasets. Here too, I would expect a different performance on the unit process level of the consequential (marginal) refinery compared to the average one.

A thorough comparison of the consequential and attributional models should compare datasets on the contents of the unit process inputs and outputs besides counting the number of datasets and their relative deviation. 

Best regards

Rolf

Written on: 30.10.2018#5

Author:
user5

Any updates on this topic?

Written on: 31.10.2018#6

Dear,

 

with the release of ecoinvent version 3.4 electricity market compositions were updated for both the attributional and consequential system models. Please read about the details of the modelling approach for electricity markets in v3.4 (and following versions) in the FAQ What is new with electricity markets in version 3.4?. If you are asking yourself How can I see the technology mix of an electricity market?, I’d invite you to consult the respective FAQ. It explains in detail how you can consult the market mix on a unit process level (by accessing the linked Unit Process Datasets (UPRs) in EcoQuery).

For many countries the attributional electricity mixes will contain imports from other countries, which in turn represent a mix of technologies and imports. Tracing the convoluted chain of imports back, eventually results in a market mix composed of exclusively electricity generation technologies. You can find this type of breakdown for electricity markets in v3.3 and v3.4 in the spreadsheet “electricity_market_composition_v3.4.xlsx” (can be found in the “Report” section of EcoQuery).

(Please mind that there were some issues with certain electricity markets in v3.4, see known issues v3.4. These are resolved in v3.5. We are currently working on the “electricity_market_composition” breakdown file for v3.5.)

 

I hope this is helpful to you.

 

Kind regards,

Florentine Brunner,

 

Data Analyst, ecoinvent