Multiple determining products
This section of the web-site addresses the consequential modelling of situations where there is multiple determining products.
To investigate the consequences of a change in demand for a specific product, it is necessary that the product system has only this specific product as its output. When the product system has more than one product output, the product of interest needs to be isolated form the other co-products.
Two kinds of co-production situations exist, namely combined production and joint production:
- In combined production the amounts of the co-products can be varied independently, and all products are therefore determining products, independently of each other. The consequences of an isolated change in demand for each of the combined products will have to be modelled separately, since they will follows physical causalities that are specific to each product. This results in separate dataset for each of the combined products. This modelling, using physical causalities is done in the same way in attributional and consequential modelling and is therefore not the main focus of this website. However, since this procedure is not always seen as straightforward, we anyway devote a page to this (see link below).
- In joint production, the amounts of co-products cannot be varied independently (i.e. the proportions are fixed). In most cases, one of the co-products can be identified as the determining product, and the remaining dependent co-products can eliminated by substitution (see by-products, recycling and waste). In a few special situations (see more than one co‑product have no alternative production), a joint production will have more than one determining product, and the consequences of a change in demand for each of these will have to be modelled separately, resulting in separate dataset for each of the determining products.
- In combined production the amounts of the co-products can be varied independently, and all products are therefore determining products, independently of each other.
- How to model the situation where a joint production has more than one product without alternative producton routes - and therefore more than one determining product.