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Avoiding “system expansion”?
December 10, 2015 by Marie De Saxcé
When producing a product footprint – or life cycle assessment (LCA) result – we want it as far as possible to be useful for decision support. Therefore, the way we model the product systems should maintain mass, energy and monetary balances intact, fully reflecting physical and economic causalities, based on empirical relations rather than normative assumptions and arbitrary cut-offs. This also implies avoiding allocation (partitioning) of systems with joint production of co-products, since this is an inherently normative procedure that cuts off part of a product system and therefore can provide misleading results.
To avoid allocation of systems with joint production, we use a procedure that the ISO 14044 standard on LCA calls “system expansion”. This makes it sound like something was missing in the original system and that a lot of additional work may be involved. But this is not the case.
When the text of the ISO 14044 standard was originally drafted, before the turn of the century, procedures for LCA were not as developed as they are now. Product systems were manually created using foreground data to painstakingly describe flows to and from nature for each unit process in the product system. Cut-offs were needed due to lack of data or time. In this context, the term “system expansion” appeared natural for describing the inclusion of modelling of the further fate of the by-products and wastes and the resulting changes (substitutions) in the product system, as opposed to cutting them off by allocation.
Today we have environmentally extended input-output (I/O) databases based on national statistics that cover the entire global economy. Our product systems are therefore inherently complete from the outset. When we perform “system expansion”, we therefore do not actually expand the product system, but simply follow the fate of the by-products and wastes within the already complete system, accounting for the increase in treatment activities and decrease of the upstream activities that supply the same markets as the useful by-products. The only manual work left today is to ensure the correct distinction between the products that determine the volume of the joint production and the by-products for which we must ensure that they are correctly linked to the markets where the substitution occurs. More details and examples of this can be found at www.consequential-lca.org.
The term “system expansion” is therefore no longer appropriate for what we do in practice, and we therefore tend to rather use the more general and neutral term “substitution” for this procedure. This is in accordance with the way “system expansion” was described in the original ISO text, as explained by Bo Weidema in a previous blog post.
Consequential vs. attributional LCA
November 19, 2015 by Bo Weidema
I often hear (or read) statements like “Attributional LCA is accounting for the total emissions from the processes and material flows used during the life cycle” which shows a lack of understanding for the large parts of the life cycles that are actually ignored in attributional LCA.
Attributional LCA uses normative cut-off rules and allocation to isolate the investigated product system from the rest of the World. And by this, it ignores a lot of the physical and economic causalities that are related to the life cycle of a product.
The below video (a simple slide-show) explains three of the issues that are included in consequential life cycle models, while not being included in attributional LCA (double-click for full screen mode).
For more information see: consequential-lca.org
consequential-lca.org
October 15, 2015 by Bo Weidema
I am really delighted to announce today a new open resource on consequential Life Cycle Assessment modelling: consequential-lca.org.
The new website is a collection of examples illustrating how to model consequential product systems in LCA as it is recommended in the ISO 14040 series. It provides free access to information, which is often hidden deep within LCA reports or even left out in brief scientific papers to save space.
consequential-lca.org is a community resource. We hope that the community of LCA practitioners will contribute further examples of good practice so that the website will grow to show solutions in as many different application areas as possible.
You can also contribute!
The development of the new website is proudly sponsored by 2.-0 LCA consultants, reflecting our 15 years of experience and commitment to consequential LCA as the scientific approach to LCA modelling.
During our 15 years of existence, we have given a lot of free advice to developers of standards and guidelines, and much of this is now collected in this new website.
2.-0 LCA consultants also continues as the main sponsor for the International Life Cycle Academy (ILCA) where you will find sustainability and LCA-related courses based on consequential thinking.
Quantifying the social footprint
September 8, 2015 by Bo Weidema
As already described in a previous blog-post on social LCA my first entry into the world of LCA in the early 1990’ies was from a social (fair trade and organic agriculture) perspective. Compared to then, we have now much better data and also better methods for social impact assessment. My role in the development of social LCA has mainly been – and continues to be – to insist on the need and feasibility of a quantitative approach to measuring social pressures and impacts, as you can find e.g. in my suggestions of social indicators and characterisation methods (Weidema 2006a, 2006b).
While developing these indicators and methods, I divided the impacts in two groups: Those that were the responsibility of and could be influenced by governments and those that industry could directly influence, and thus be responsible for. Since most LCAs not to evaluate public governance, but rather for industries, I disregarded the former and focused on the latter.
I now realise that this was a mistake. Because industry plays a key role in influencing governments. And it makes all the difference whether industries play their roles passively, taking advantages of low labour costs or even perpetuating the unfair distribution of resources, or whether they play active and positive roles, by paying taxes – directly or indirectly – and creating shared value in their societies. This choice – between a passive and an active role – implies a co-responsibility of industries for the current state of the economies in which they operate. And using this concept, we have now found a way to quantify the overall social impact that an industry (and its products) has, both positively (in re-distributing income to low-income groups and by actively contributing to activities that create shared value together with the local communities) and negatively (via the co-responsibility for the missing local governance that comes with low labour costs). The net impact, measured in utility-weighted monetary units, we call the “social footprint”.
The quantification of the “social footprint” is based on the concept of potential productivity (Weidema 2009) and the quantification of relative income inequality (Layard et al. 2008), and has become possible due to the recent availability of global input-output databases with a high country and sector detail, such as EXIOBASE and EORA. Using standard LCA methodology, the “social footprint” provides a top-down aggregated value of all the externalities related to human activities, both biophysical, economic and social, and a breakdown by country and industry.
In contrast to other social LCA methods it does not initially require site-specific data and does not provide a breakdown of all the possible contributing impacts. Further development of the method will provide more details on specific social impact categories. For inclusion of positive impacts from creating shared value in the local social hotspots identified by the method, company-specific data will of course still be required. We first presented, shared and further developed the method and database through the social LCA club (work is now continued in the LCSA-club)
References
Layard R, Nickell S, Mayraz G. (2008). The marginal utility of income. Journal of Public Economics 92:1846–1857.
Weidema B P (2006a). The integration of economic and social aspects in life cycle impact assessment. International Journal of Life Cycle Assessment 11(1):89‑96. https://lca-net.com/p/1024
Weidema B P (2006b). Social impact categories, indicators, characterisation and damage modelling. Presentation for the 29th Swiss LCA Discussion Forum, 2006‑06‑15. https://lca-net.com/p/1021
Weidema B P (2009). Using the budget constraint to monetarise impact assessment results. Ecological Economics 68(6):1591‑1598. https://lca-net.com/p/194