I am confused with the "type" properties in Brightway and how they influence the LCA modelling in Brightway.

There are several possible types which seem to hold different meanings, it is even possible to add custom ones according to the documentation. I work with Excel LCI to import my data in Brightway.

First, it seems that I should differentiate the activity "type" property (located before exchanges) and the exchange "type" (exchange column).

Q1: Should Activity use a type value among node types and Exchanges among edge types?

Q2: Under what condition should I specify a "type" for an Activity in the context of Excel foregrounds? I’ve seen examples where not every Activity had a "type" specified, which makes me think that Brightway infers their type, but the logic is not transparent to me.

I saw examples where the activity type was just "process", other situations when it was not specified in the Excel LCI Brightway automatically set it to "processwithreferenceproduct".

Q3: Considering this, should I ever have to use "multifunctional", "product" and "emission" types?

For elementary flows related to an activity, the exchange "type" has to be "biosphere", according to the Excel template found in the official learning materials.

Q4: It seems that if I have custom elementary flows, their type in the Excel should be "emission", while exchanges should still be "biosphere", is that correct?

Q5: For technosphere exchanges, should I use "technosphere" when it is a consumption and "production" when it is a co-product?

Q6: While "substitution" type would be required for substituted products of a multi-output process in the case of consequential LCA.

I have heard that the type property provides information on the directionality of the flow (i.e., input vs output).

Q7: How do can we differentiate consumed biosphere and emitted biosphere exchange using the "type" property?

This probably all comes down to me not understanding Brightway glossary well, or that there are some information missing or unclear.

The different default and possible values are visible in configuration.py located in lib/python3.1/site-packages/bw2data/configuration.py (direct Github link)

class MatrixLabels(BaseSettings):
    lci_node_types: List[str] = [
        "process",
        "product",
        "processwithreferenceproduct",
        "multifunctional",
    ]
    other_node_types: List[str] = []
    process_node_types: List[str] = ["process", "processwithreferenceproduct"]
    product_node_types: List[str] = ["product"]

    process_node_default: str = "process"
    multifunctional_node_default: str = "multifunctional"
    chimaera_node_default: str = "processwithreferenceproduct"
    product_node_default: str = "product"
    biosphere_node_default: str = "emission"

    biosphere_edge_types: List[str] = ["biosphere"]
    technosphere_negative_edge_types: List[str] = [
        "technosphere",
        "generic consumption",
    ]
    technosphere_positive_edge_types: List[str] = [
        "production",
        "generic production",
        "substitution",
    ]
    # You should normally use `technosphere_positive_edge_types`, as it includes substitution
    substitution_edge_types: List[str] = ["substitution"]
    other_edge_types: List[str] = []

    production_edge_default: str = "production"
    consumption_edge_default: str = "technosphere"
    biosphere_edge_default: str = "biosphere"
    substitution_edge_default: str = "substitution"
...

Versions:

• bw2data: 4.5
• python: 3.12.11