CO2 : Expense Reports

This module brings carbon accounting into the Expenses app. Each expense line now carries a CO2 value (carbon debt) that Odoo computes automatically from the product or the expense account used, based on the line's quantity, amount, date and company currency. The value is recalculated when the product, account, quantity, total amount or date changes, and only while the expense is still in draft.

On the expense line form, a CO2 field appears next to the taxes, with a small lock/unlock button. Locking the value stops Odoo from recalculating it; unlocking lets it be recomputed again.

The same CO2 field and lock/unlock button are also shown on the expense report (sheet) form, just before the total amount, so approvers can see the carbon impact of the whole report.

When an expense is posted to accounting, the carbon debt and its locked status are copied onto the resulting journal entry line, so the carbon information follows the expense into the books.

Expense lines are treated as carbon inflows (purchases/consumption). The module relies on the general sustainability module for the carbon computation logic and only adds the expense-specific wiring and screens.