Rigorous LCA

A rigorous LCA has to be made according to the ISO 14040 series (especially 14044: 2006). The Handbook on Life Cycle Assessment of the EU (see tab data > references 7.1) provides the “translation” of these ISO definitions in a comprehensive guide for experts
This webpage is not meant to replace this Handbook, but gives a general introduction on the subject for non-specialists so they will understand the main principles. A practical guide for non-specialist is available at https://www.delftacademicpress.nl/b018.php .

For some (simplified) definitions, see see Fig. 5.2a. Three aspects of these definitions are important:
– the difference between LCI and LCA
– the difference between LCA and LCC
– how to deal with “from cradle to gave” in real life calculations

An LCI is not more and not less than the result of a mass balances and an energy balances of the system, as it is common practice (already for many decennia) in chemical engineering. Essential is a choice of proper boundary limits of the system which is studied.

Figure 5.2a. Some definitions in LCA

In the classical approach, special software is needed to add-up all LCIs of the sub-systems (Open LCA, Simapro), and after that analyze the big (total) inventory list. The issue is here that such an inventory list comprises often 500 – 2000 emissions, so a method is needed to compress this long list in some indicators that do make sense to the LCA practitioner.
There are a few methods to combine the substances

Content

of the long total list to one or a few indicators. The basic idea is that the substances are combined according their effect in nature (Carbon footprint, Acidification, Eutrification), the effect in terms of human health (toxicity, fine dust, COPD), or the effect on resource

scarcity (metals, water, land-use). Nature, human health, and resource scarcity, are called ‘Areas of Protection’. The level under AoPs (carbon footprint, acidification etc.) are called ‘midpoints’.

The norm for LCA, ISO 14040 & 14044 describes the calculation sequence in 4 steps, see Fig. 5.2b.
At the previous webpage, LCA the basics, the first two steps have already been described, in general terms of the tasks for the LCA practitioner. In the 3rd step of “Fast Track” LCA, the practitioner can directly apply excel tables, since the indicator has already been chosen in the 1rst step in line with the goal of the study (as is required by the ISO14044). In the classical, rigorous approach, however, the choice of the indicator is postponed. It requires computer software add-up all the LCIs from the sub-systems first, and then combine all the substances from the total LCI in midpoints and endpoints. This process is depicted in Fig. 5.2c. and has the advantage that the practitioner can switch from indicator at this late stage of the procedure. It has the disadvantage, however, that the practitioner can easily change the indicator when he or she thinks that the conclusion is not convenient.

Figure 5.2b. The 4 phases of LCA as described in the norm for LCA: ISO 14040 and 14044

At the Delft University of Technology we normally apply either ReCiPe 2016 (a damage based model), the eco-costs 2022 (a prevention based model), or the carbon footprint. These models transfer the LCI data in one single indicator for LCA.

Fig. 5.2c. The way elementary susbstances are converted to midpoints, area of protection, and endpoints

The road to a single indicator (“impact assessment”, phase 3) is defined in 4 subsequent steps:

(1) classification = making groups of emissions for each type of impact category (e.g. global warming , acidification, etc.)
(2) characterisation = creating “equivalent” emissions per type of impact category by taking into account the relative impact of each emission (resulting in kg CO2 equivalent, etc.)

(3) normalisation = comparing the equivalent emissions to the total emissions of that class in the EU or in the world (note that at the level of the world a accurate data are lacking)
In monetary systems normalisation results in the relative importance, which is determined by the “marginal” economic costs (of damage or prevention)
(4) weighting = adding the relative importance by a panel of experts

Some remarks:

Note 1: in monetary systems the weighting step is not required: the parameters are set to 1.
Note 2: there are to types of results at the end of step 4: (a) bundle of impact categories in terms of ‘Areas of Protection’ (b) ‘single indicators’ for LCA, where the Areas of Protection are bundled as well
Note 3: the carbon footprint is a so called ‘single issue’ indicator (a ‘midpoint’ result at the level of step 2.

The advantage of a single indicator (as well as AoPs) is that there are tables available for subsystems, see data, which makes the impact assessment step in LCA simple: “Fast Track” LCA

Example:
As an example, the LCI of different types of paper (recycled from waste paper as well as paper from wood) is given in the pdf file “corrected FEFCO database 2003“. This document is an excellent example how reporting on LCI must be: it provides a clear description of the system boundaries, on what has been calculated and how. Excel sheet “testliner FEFCO 2003” (testliner is 100% recycled paper) shows how the LCI data are multiplied by the appropriate impact assessment factors to arrive at eco-costs.

Confusing issues.
For people who start with the LCA method in practice, there are 2 confusing issues:
(1) An LCA must always be done on the basis of “from cradle to grave”, so the LCI of the total system must

comprise the total life cycle chain “from cradle to grave” or “to cradle”. However, nearly all data from databases are of LCA’s of subsystems (not from cradle to grave). Most of the data on materials and electricity are given for “from cradle to finished product”. Data are also available for the subsequent steps of the life cycle chain (e.g. use phase and End of Life phase). So databases provide components (subsystems) of the total system, which have to be combined carefully to construct the total system.

Another confusing aspect for people who start with LCA is how to deal with impact assessment (phase 3 of LCA). A decennium ago it was assumed that the end result of the assessment step could only be a set of ‘midpoint’ indicators. Now it is generally accepted that a single indicator for LCA is preferable.
As such this is an extremely complex issue, and therefore it is a field of debate for specialized scientist only. For LCA practitioners it is not necessary to know all the details. It is only necessary to select one of the many models of impact assessment.

Foreground an Background systems

It is important to distinguish between foreground systems and background systems. Foreground systems are the systems which are under study, and of which the emission flows out of the system boundaries are known. The eco-costs scores of such emissions are provided in the “Ecocosts 2022 midpoint tables” at the webpage data. Background systems are systems that deliver functions to

Figure 5.2d. Foreground and Background systems in LCA

the foreground systems, such as electricity, materials, transport. The data on eco-costs (or ReCiPe points, carbon footprint, etc.) are from databases with LCIs of generic processes that have been pre-calculated based on averages. These data can be found at the Idemat and Ecoinvent excel tables. The background data are applied for upstream as well as for downstream processes outside the boundary limits of the foreground process. See Fig. 5.2d.