Brightway2-aggregated is an extension to the Brightway2 LCA framework to generate aggregated data.

It operates at two levels:

  • aggregated LCI level (cradle-to-gate inventories), though this is not recommended because Brightway2 is optimized to work with sparse matrices, and the biosphere matrix of aggregated LCI databases are very dense)
  • aggregated LCIA score (cradle-to-gate impact assessment score)

The DatabaseAggregator will calculate the LCI (and, optionally, the LCIA) for all activities in the database and store the results in a new database. The activities in the resulting database will:

  • have a production exchange identical to the production exchange in the unit process database

  • have no further technosphere (i.e. there will be no off-diagonal elements in the A matrix)

  • Have either:

    • cradle-to-gate LCI results stored as biosphere exchanges (resulting in a dense biosphere matrix B), or
    • cradle-to-gate LCIA results stored as biosphere exchanges. The biosphere matrix (B) will therefore have as many rows as there are impact assessment methods of interest. This entails the creation of new “unit impact” biosphere exchanges, see the section on preparing Brightway2 for use of cradle-to-gate scores

While there are many reasons for using aggregated data, this module was specifically created to play well with presamples, where aggregated data can be associated with presampled data generated from e.g. Monte Carlo simulations.