Page 40 - Materials Chemistry, Second Edition

Life cycle assessment in practice

s is simplified, pragmatic, feasible, practical, flexible, fast and easy to use 27
s represents the most important environmental burdens
s focuses on key impact areas
s limits consideration of effects to first-order impacts
s leaves out some life cycle stages or impact categories
s uses available information to simplify the process
s is less comprehensive
s is more ‘do-able’ (Weitz et al. 1996).
These practitioners described various approaches to streamlining LCA, usually involving
one or more of the following: narrowing the study’s boundaries, targeting specific issues and
using readily available data, including qualitative data.
The principal question to be addressed before embarking upon any streamlined LCA
involves the appropriate level of trade-off of accuracy or depth in results that is acceptable in
exchange for the reduced effort in undertaking the evaluation. The colloquial term ‘quick and
dirty’ is often applied, which sums up this trade-off. Quick and dirty LCAs invariably limit the
time spent on data collection by using existing data available in public databases often already
integrated into LCA software. This involves the use of data from other regions, proxy processes
for data that is not available, and the exclusion of many minor processes such as material trans-
formations, intermediate transport and so on.
Quick and dirty studies may be sufficient in themselves to address some LCA questions
and can be used to scope larger projects. Skill and experience is required to understand the
potential influence and significance of using data from other regions or different technological
processes. Since one of the key aspects of LCA practice is learning the dynamics of the life cycle
system being assessed, including how results change when parameters in the study are varied,
quick and dirty LCAs can contribute to this understanding without producing an answer to
the LCA question in sufficient detail or confidence for publication.
By their nature, quick and dirty studies are not usually published, but are used for internal
decision-making. By way of illustration, a study was undertaken for the federal government
on biodegradable plastics in 2002 (Nolan-ITU 2002). Environment Australia, in consultation
with the Plastics and Chemicals Industries Association (PACIA), engaged consultants to
undertake a national review of biodegradable plastics to identify and characterise emerging
environmental issues associated with biodegradable plastics. Rather than conducting a full
LCA, the consultants identified the various types of biodegradable plastics available, key
environmental and technical issues associated with their use and disposal, particularly recy-
cling, and a range of potential waste solutions. The streamlined LCA was then conducted on
these options, modelling each of the biopolymers from available public data and studies,
which in some cases were very limited. The results distinguished a significant difference
between reusable ‘green bags’ made from polypropylene and single-use bags, but could not
conclusively answer whether the biopolymer or conventional polymer bags had more signifi-
cant impact, considering the limited quality of the data and the closeness and conflicting
nature of the results.
Another approach used in streamlined LCA is to reduce the impact indicators and thus
reduce the scope of the study and the resources required to undertake it. While reducing the
indicators has the potential to reduce data collection, particularly data on elementary flows,
there are two additional tasks to be undertaken. First, where indicators are to be reduced,
careful consideration is required to identify those indicators of primary interest to the study so
that the shortened list of indicators covers the key contestable issues. While the goal and scope
can be used to exclude any indicators, the value of the study will be very limited if basic ques-
tions posed by stakeholders are not addressed. Second, at the conclusion of the streamlined
study, the practitioner should comment on and contextualise the results against indicators

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