Choice of allocations and constructs for attributional or consequential life cycle assessment and input-output analysis

The divide between attributional and consequential research perspectives partly overlaps with the long-standing methodological discussions in the life cycle assessment (LCA) and input-output analysis (IO) research communities on the choice of techniques and models for dealing with situations of coproduction.

The recent harmonization of LCA allocations and IO constructs revealed a more diverse set of coproduction models than had previously been understood. This increased flexibility and transparency in inventory modeling warrants a re-evaluation of the treatment of coproduction in analyses with attributional and consequential perspectives.

In the present article, the main types of coproductions situations and of coproduction models are reviewed, along with key desirable characteristics of attributional and consequential studies. A concordance analysis leads to clear recommendations, which call for important refinements to current guidelines for both LCA/IO practitioners and database developers. We notably challenge the simple association between, on the one hand, attributional LCA and partition allocation, and on the one hand, consequential LCA and substitution modeling.

Mots clés

coproduction; by-product; joint production; system expansion; substitution; multifunctionality