Python based tools for working with LCA foreground model disclosures
Disclosure framework based on "Disclosure of product system models in life cycle assessment: achieving Transparency and Privacy" by Brandon Kuczenski in J Ind Ecol. (doi: 10.1111/jiec12810)
This package was originally authored by James Joyce. Code and testing related to Brightway 2 have been branched into the lca_disclosures_bw2 repository so as to remove dependencies from the core program. The original repository lca_disclosures is still operational.
The lca_disclosures repository supports the generation of a disclosure specification from the following software:
Support (and testing) for Brightway2 is available in the original repository lca_disclosures.
To use the disclosure framework, instantiate the appropriate Disclosure subclass and supply it with the software-specific input data. The disclosure object can be used to answer questions about the model:
- listing foreground flows, background flows, and emissions;
- identifying cutoff flows (flows that exit the model boundary with no impacts);
- performing an aggregation of the model into a unit process
The disclosure object can also be serialized to JSON or saved as an Excel spreadsheet.
pandas, to write to excelscipy, to perform matrix operations
A disclosure has six parts, including three lists of flows:
- i An ordered list of foreground flows, beginning with the functional unit of the system (length = p);
- ii An ordered list of flows from background processes or activities (length = n);
- iii An ordered list of environmental or social "emissions" (length = m).
And three sparse matrix specifications:
- iv A list of nonzero entries in the p x p sparse matrix defining the foreground;
- v A list of nonzero entries in the n x p sparse matrix defining the foreground's dependency on the background;
- vi A list of nonzero entries in the m x p sparse matrix defining the foreground's direct emissions.
A visual representation of the disclosure is found in Figure 3 of the above paper:
The base Disclosure class is abstract, and a subclass must be created for each supported software type. A subclass must populate the following methods:
_prepare_efn()returns the evaluated filename used to store disclosure serializations._prepare_disclosure()returns a 6-tuple corresponding to the 6 disclosure elements, in the order listed above.__init__()must be written to handle input data and then call the superclass__init__, which computes_prepare_disclosure()and stores the output.