Page 152 - Materials Chemistry, Second Edition

136 3 Life Cycle Inventory Analysis

phases that cause high burdens. This is done in the context of the so-called sectoral
analysis in the interpretation phase (see Chapter 5).
In the LCI, weighting or valuating aggregations are to be avoided. Examples were
the ‘critical volumes’ according to BUWAL 182) (see Section 4.2). These aggregation
types should rather serve as early forms of the LCIA. 183) To the same category belongs
the controversial aggregation per mass (sum of all mass movements, inclusive of
spoils) called Mass Intensity per Service Unit (MIPS). This method proposed by
Friedrich Schmidt-Bleek 184) is based, similar to the CED, on the search for a
simple, universal measure for the ecological loads (similar to money in economics)
emanating from a product. Given the allowed equation ‘service unit = functional
unit’, the MIPS method can essentially be seen (apart from aggregation) as a
LCI. Besides, MIPS cut off small mass flows and therefore the common trace
emissions, according to the motto ‘megatons, not nanograms’. It is, however,
erroneous to assume that MIPS can be determined easier than, for example, CED,
because a sound inventory (even without trace emissions that are not included in
MIPS) is always necessary. Of course, all problems discussed above as those of
allocation, data quality, and so on, also apply to the MIPS method, just as with an
LCA-inventory. ‘MIPS’ is only easier if the LCI is conducted with low quality.
In comparison to CED, however, MIPS has the advantage of a higher clarity (mass
vs energy) captured in the colloquial expression ‘ecological backpack’ (= MIPS).
It designates, for example, how many tons (rock) have to be moved to produce
1 g catalyst from noble metals. This clarity cannot usually be achieved with energy
units unless by use of (non-standard) coal equivalents (ce) 185) in tons (tce) or kg
(kgce) standard coal; this is an energy unit, disguised as mass (see Section 3.2.3.1).
Neither the MIPS method nor a mere calculation of CED provides LCA-results
according to ISO 14040/44.

3.6
Presentation of Inventory Results

The representation of an inventory analysis with its plethora of single data is often
a tightrope walk between transparency and legibility. To ensure both, a main part
with few tables and pictures can be supplemented by an appendix or a material
volume (or a CD), containing all original data and intermediate results.
In an LCI study, 186) the Goal and Scope definition including all assumptions,
fUs, system boundaries, and so on, must not be missing. Furthermore, in this
case an interpretation with a discussion must follow. Above all, it should be
illustrated whether data quality and statements show a reasonable relationship.
This is achieved by sensitivity analyses (see Chapter 5).
182) BUWAL, 1991.
183) Kl¨ opffer, 1994, 1995; Kl¨ opffer and Renner, 1995.
184) Schmidt-Bleek, 1993, 1994; remember the famous motto: ‘Megatons, not nanograms’.
185) 1kgce = 29.3 MJ.
186) The acronym LCI stands according to ISO 14040 (§ 3.3) for ‘Life Cycle Inventory analysis’, the
second phase of a full LCA. It is also used sometimes for ‘Life Cycle Inventory study’, a truncated
LCA without the third phase, LCIA.