On openLCA Nexus, we have recently published a modified version of Agribalyse v3.0.1. This modification was needed to correct the predefined allocation factors, which are parameterized in Agribalyse, or expressed as formulas. As you probably know, in openLCA, you can specify the type of allocation (physical, or economic, or causal, which is entirely free to define), and select this for the calculation, and thus additional parameterization of allocation factors probably does not add much; in SimaPro, you need to address different allocations via allocation parameters (Figure 1).
Figure 1: Parameterized outputs and co-products in SimaPro
Agribalyse, further, contains unparameterized formulas in the allocation factors for documentation reasons. An example below:
Figure 2: unparametrized formula in allocation factor in SimaPro
Figure 3: synonymous dataset in openLCA, with unparameterized allocation factor incorporated in the amount
At the moment, openLCA 1.10.3 does not deal with parameterized allocation factors; while we are thinking to include this in future versions, for Agribalyse and now, we provide the Agribalyse database with a workaround that ensures to obtain the same results when changing the parameters in the allocation, as follows:
- All processes that appear in the databases and have multiple product outputs associated with parameterized allocation factors have been modified. To elaborate, we have corrected the amount column for all product outputs so that these include the allocation factor already. Mathematically, this has been solved by dividing the amount value by the allocation factor (see Figure 4).
Figure 4: parameterized output and co-products in openLCA
- To avoid a division by 0, three processes have been adjusted manually by changing the amount of specific product flows:
What are the implications for users?
- As the allocation factors are critical for correct results, for these processes and life cycle models that use these systems, we strongly recommend working with the updated version 3.0.1 from Agribalyse, which can be freely downloaded via openLCA Nexus.
- In openLCA, for allocation method, select ‘As defined in processes’ should be selected for the calculation(Figure 5). Needed changes to the allocation can be obtained by changing the parameters used in the allocation factors.
Figure 5: calculation window in openLCA
- This version of the database includes EF 3.0 method; other LCIA methods can be freely downloaded via openLCA Nexus.
Land use inconsistencies
Additionally, we observed an inconsistency that leads to varying results between SimaPro and openLCA in the impact category ‘land use’ when applying the EF v3.0 method. Agribalyse uses some processes from ecoinvent. In the past, ecoinvent had implemented a name change of the land use class for ‘Occupation/Transformation from, /Transformation to, permanent crop, fruit’ (in version 2) to ‘Occupation/Transformation from, /Transformation to, permanent crop, irrigated’ (in version 3).
It was observed that for Agribalyse in SimaPro, there are now two separate flows (of the old and new category), but only the new category is considered in the LCIA. Since both flows should be included to get correct results, openLCA includes both classes in the EF 3.0 to be considered in the LCIA calculation. Therefore, land use results are logically higher in openLCA than in SimaPro, and this is correct. More information on the changes in the Land use categories implemented by ecoinvent can be found here.