Page 143 - Materials Chemistry, Second Edition

128 A. Bjørn et al.

Fig. 9.3 4-Step approach for
identifying affected process in
Supply
a full consequential LCA 1. Change in demand or supply?

Demand
Not
constrained
2. Identify constraints in the market

Constrained

3. Product substitution

Substitute identified

4. Identify production technology
affected by change in demand

We recommend solving this task by following a 4-step procedure shown in
Fig. 9.3. Depending on the concrete case, one or more steps can be skipped (as will
be explained below).
Step 1: Change in demand or supply?

When performing a consequential LCI, full elasticity of supply is generally
assumed. This implies that a change in demand for some function will lead to a
change in supply of products that can fulfil this demand, but that change in supply,
will not lead to a change in demand. There will therefore be a difference between
the market effects of changing demand and changing supply, as will be visible in
the steps below.
First step in the procedure is therefore to consider whether the question at hand
addresses a change in demand or supply; e.g. are we assessing the question: “What
happens if I demand more/less of X?” or the question “What happens if I supply
more/less of Y?” Note that handling a co-product from a multi-output process in the
studied life cycle relates to changes in supply of this co-product, and therefore is
related to the latter type of question.
If the assessed decision relates to changes in demand, go to Step 2. If it relates to
changes in supply, go to Step 3.