Parameter scenario files

How to structure Excel or CSV files when you want to vary Brightway parameters across scenarios in Activity Browser.

What this file type is for

Parameter scenario files list which parameters you want to touch and what values they take in each named scenario (column). Activity Browser uses the same parameter definitions, groups, and formulas already stored in your project.

On import, a parameter scenario file is converted automatically into an internal flow (superstructure) scenario table: the tool resolves formulas, finds the affected exchanges, and builds the rows expected for calculation. You normally edit parameters; the software derives the flow-level changes.

You can save or export the scenario from the calculation setup like any other scenario table; the exported file will be in flow scenario form (superstructure columns plus scenario value columns), not in the original parameter layout.

Required columns

The importer recognizes a parameter scenario file when the table contains exactly these two headers (spelling and casing matter):

  • Name — Brightway parameter name, as in the Parameters tables.
  • Group — Parameter group, as in Brightway: e.g. project for global parameters, a database name for database-scoped parameters, or the activity parameter group for activity-scoped parameters.

Every other column (except the optional default column below) is treated as a scenario: its header becomes the scenario name, and the cells are numeric overrides for that scenario.

Optional default column

You may include a column named default (case-insensitive: default).

  • It is only for your own reference (documentation, reporting, or sharing the file with colleagues).
  • Activity Browser does not use this column when building scenarios or evaluating formulas. It does not act as a fallback value for empty scenario cells.

So: keep default if it helps you document intended baselines, but the calculations rely on project data and the scenario columns, not on that column.

Scenario columns and empty cells

Each scenario column holds the value you want for the given (Group, Name) parameter in that scenario.

  • If a cell contains a number, that value is applied for that scenario (and, for parameters that also have a stored formula, an explicit cell overrides the formula for that parameter in that scenario so your number is respected).
  • If a cell is empty (or otherwise missing), Activity Browser does not treat that as “read the default column”. Instead, the parameter keeps the amount currently stored in your Brightway project for that parameter when the scenario row is filled in. In other words: leave a cell blank when you want no change from what is already in the database for that parameter in that scenario.

If you need every scenario to start from a specific baseline you only have on paper, either enter those numbers in each scenario column or update the parameter amounts in Brightway first; the spreadsheet default column alone will not enforce that baseline in the tool.

Practical layout example

Name Group default Low COP High COP
COP my_foreground_db 3.5 3.0 4.2
P1 my_foreground_db 1.0   1.1
  • Low COP and High COP are two scenarios.
  • The default column is optional documentation; it is ignored by the conversion.
  • Empty P1 under Low COP means: use the stored project amount for P1 in that scenario.

Scenario columns keep the order they have in the file in the resulting flow scenario table.

What gets converted to flows

The conversion considers formula-bearing exchanges linked to your parameters, in line with your model. The set of Group values that appear in the file helps determine which output databases / scopes are in play. Parameters that only exist in the file but not in the project, or rows with no matching exchanges, can lead to errors or empty results—your parameter definitions should match the project.

File formats and import

You can use the same formats as for other scenario imports supported in the Calculation Setup (e.g. Excel .xlsx / .xls, CSV). The file is read as a table; ensure Name and Group are present so Activity Browser selects parameter scenario mode rather than a raw flow scenario file.

  • Scenario calculations — combining scenarios, extending scenarios, and the difference between parameter and flow scenarios at a high level.