Abstract
One of the main issues in a LCA is the modeling of the product tree in the LCI phase. In the current
practice there are different alternatives for modeling a product tree. In
particular there is the classical
sequential process based inside – outside modeling method, the respective one outside – inside
method and the matrix modeling method. The system boundaries between the product system
sequential process based inside – outside modeling method, the respective one outside – inside
method and the matrix modeling method. The system boundaries between the product system
and
the technosphere are determined according to the ISO 14040 standards by
using the defined
by the practitioner cut-off criteria.
by the practitioner cut-off criteria.
In this study, LCIs referring to the energy production in European countries were developed and
investigated.
The aforementioned different product system modeling methods were applied.
Differences
on the product system boundaries were identified when the same cut-off
criterion is
applied.
Thus, analysis of the different approaches was undertaken. A built up hierarchy
among
the unit
processes has an important role for the differences in the process based
methods.
In the
matrix method the crucial parameter is the intermediate product flow
of the unit process. The found methodological differences suggest
that the different modeling methods (process based
inside-outside,
outside-inside and matrix method) develop differently the product trees
regardless
from the
product system that is investigated.
2nd International Exergy, Life Cycle Assessment,
and Sustainability.Workshop &Symposium (ELCAS-2).
Nisiros - Greece, 19-21 June 2011.
Keywords: LCA, Sustainability, Modelling