Environmental Engineering Reference
In-Depth Information
Figure 2.7
Definition of “life cycle” in LCA exercises.
For example, LCA studies on identical poly(ethylene terephthalate) (PET)
soda bottles produced at two plants can have very different embodied
energies because their process electricity is derived from different sources
(coal vs. hydropower) or because modes of transportation or the distances
in the distribution networks are different or even because they use different
disposal methods. Mechanical recycling, where available, can make a very
significant differences to both the energy and carbon footprint of the
product. A technically “recyclable” product should not be credited with
saved energy in the LCA unless the infrastructure is actually present to
recycle it.
A detailed discussion of how to carry out an LCA for a product is outside
the scope of this volume. Several excellent sources of such information are
available (Curran, 2012; Horne et al., 2009). In general, the process is made
up of four steps:
1. Definition of goals and the scope of analysis. Goals clearly formulate the
reasons to carry out the study and how the findings will be used. Often,
