National audienceIn this paper, we refer to a socio-technical system as a model for the organisation of production and consumption in a given territory. This work is part of the STEEP team's "Socio-technical alternatives" research axis, which aims to provide tools and methodologies that allow stakeholders in a territory (public authorities, associations, companies, citizens) to deliberate in order to imagine and evaluate together long-term alternatives (two or three decades) for their territory. These alternative socio-technical systems should meet the needs of the populations while being compatible with various local and global constraints and limits (environmental, social). Our work focuses more specifically on a step-by-step tool for designing coherent alternatives

Courtonne, Jean-Yves

Mandil, Guillaume

Mauviel, Olivier

Sturm, Peter

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HAL Id: hal-03534024https://hal.inria.fr/hal-03534024Submitted on 19 Jan 2022HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.L’archive ouverte pluridisciplinaire HAL, estdestinée au dépôt et à la diffusion de documentsscientifiques de niveau recherche, publiés ou non,émanant des établissements d’enseignement et derecherche français ou étrangers, des laboratoirespublics ou privés.Modular approach to material flow analysisOlivier Mauviel, Jean-Yves Courtonne, Guillaume Mandil, Peter SturmTo cite this version:Olivier Mauviel, Jean-Yves Courtonne, Guillaume Mandil, Peter Sturm. Modular approach to materialflow analysis. FRCCS 2021 - French Regional Conference on Complex Systems, May 2021, Dijon,France. pp.1-3. ￿hal-03534024￿Modular approach to material flow analysisOlivier MAUVIEL, Jean-Yves COURTONNE, Guillaume MANDIL, Peter STURMÉquipe STEEP - Univ. Grenoble Alpes, CNRS, Inria, Grenoble INP, LJK, 38000 Grenoble, France5/04/2021In this paper, we refer to a socio-technical system as a model for the organisation of production andconsumption in a given territory.This work is part of the STEEP team’s "Socio-technical alternatives" research axis, which aims to providetools and methodologies that allow stakeholders in a territory (public authorities, associations, companies,citizens) to deliberate in order to imagine and evaluate together long-term alternatives (two or three decades)for their territory. These alternative socio-technical systems should meet the needs of the populations whilebeing compatible with various local and global constraints and limits (environmental, social). Our workfocuses more specifically on a step-by-step tool for designing coherent alternatives.1 Material flow analysis, a tool for reconciling socio-technical sys-temsThe monetary or material flows of a socio-technical system can easily be modelled on the basis of use-supplytables.National accounting, in order to describe the functioning of the economy as a whole, often uses this frame-work in which sectors are distinguished between which product flows circulate. These flows are summarisedin two matrices with products in the rows and sectors in the columns. The first matrix, the Supply table,indicates where the products come from. The second, the Use table, shows where they go.The national accounts use the monetary unit but there is no limitation on the choice of the unit ofmeasurement. Thus, the use-supply formalism can be used to describe a socio-technical system from a bio-physical point of view (unit of mass, unit of energy, etc.), which makes it possible to study the environmentalsustainability of the system.The national accounts have an efficient data collection and processing network, which explains the qualityof the use-supply tables they produce. In general, when data are collected to fill in tables, they are incomplete,uncertain and inconsistent with each other, for example when they come from different sources or simplywhen the sources are missing. The material flow analysis ([1], [2]), of which a diagram is given in figure1, makes it possible to obtain "reconciled" use-supply tables from "raw" use-supply tables, i.e. incomplete,uncertain and inconsistent. More precisely, by solving a constrained optimisation problem, one obtains use-supply tables that are close (in the least squares sense) to the initial tables and which, in addition, verify acertain number of constraints. For example, it can be imposed that the quantity entering a sector is equal tothe quantity leaving the same sector (material-sector balance). Or one can impose that a product is producedas much as it is used, there is no "leakage" in the system through which the product arrives or leaves (productmaterial balance). There are other constraints, all linear, which we will not list here.While the reconciled tables give an ideal, because coherent, image of a socio-technical system, the com-parison with the initial tables gives retrospective information on the quality of the input data or on themodelling hypotheses. With this comparison, one can judge the improbability of the magnitude of a givenflow or the poor estimation of the uncertainty of another.2 Modules for modelling alternativesThus, material flow analysis can be used to model existing socio-technical systems. However, this frameworkcan also be used to study systems that are modelled but do not exist and whose plausibility we want to1question, which we call socio-technical alternatives. A diagram of the reasoning is given in Figure 2, whichis detailed below.In this case, the method can no longer be data collection - reconciliation - comparison with the collecteddata, because the data does not exist. It is the modelling of the socio-technical alternative that provides thedata. To carry out this modelling, we will build modules.From a formal point of view, a module is a function that takes indicators as variables and gives the valuesof certain flows as output. To construct a module, we must first define the set of flows whose values will becalculated concomitantly. There is a modelling choice here consisting of isolating, within the socio-technicalalternative that we wish to study, a subsystem that functions in a coherent manner. In the context of anagricultural sector alternative, we are thinking, for example, of the livestock farming subsystem or the soilcultivation subsystem.Once this subsystem has been defined, the indicators needed to determine the flows in question areidentified. The list of indicators and their combination in calculations to obtain the value of the flows givesa quantitative description of the functioning of the sub-system. For the livestock subsystem, indicators ofherd size, feed requirements, meat or dung production come to mind. In this case, it is important to combinethis quantitative table with a more qualitative description of the module, a narrative account that makes itpossible to identify the different aspects and the overall coherence. This dual quantitative-qualitative levelmakes it possible to check that the module has a real internal skeleton.As the scope of a module only covers certain flows, it may be useful, in order to describe a socio-technicalalternative, to use different modules, each one modelling a sub-system making up the alternative.3 Reconciliation and control of modulesOnce the value of different flows has been calculated with the modules, a reconciliation is performed. From ageneral point of view, the comparison between the data calculated by the module(s) and the reconciled datagives an appreciation of the likelihood of the alternative. Thus, a socio-technical alternative model providingdata that would be subject to too much reconciliation would be a model for which it can be said that thealternative it describes could not happen in reality, as its functioning is not coherent or balanced1.More precisely, because of the construction of the modules, we will not be led to judge the plausibilityof the alternative as such, but specifically of the set of indicators that we have combined to obtain thevalue of certain flows. Thus, given one or more modules, some families of indicators will be admissible, i.e.the flows obtained from them will be poorly reconciled, and other families will not, without calling intoquestion the entire construction of the modules. On the other hand, the size of the space of the admissiblefamilies will allow an appreciation of the capacity of the socio-technical alternative to absorb modificationsin the organisation of production. A socio-technical alternative for which the space of admissible families isvery limited is thus a fragile alternative. This assessment can then be used in a more general study of theplausibility of the alternative, while not exhausting it.It is also information on the compatibility between the different modules involved in the modelling ofthe alternative. Taking the agricultural example again, we can imagine (and this is an assumption) that thespace of admissible families associated with an intensive crop production module and an extensive livestockmodule is relatively restricted.We may therefore be interested in doing a reverse reasoning, i.e. to find, from one or several modules, thefamilies that will be admissible. This amounts to looking for the antecedents of the data reconciled by themodule functions.In this way, we can distinguish certain indicators, for example those that we consider to be the mostrelevant for summarising the socio-technical alternative or those on which we have information, and studyhow the determination of these indicators delimits the values that the others can take in order to obtain anadmissible family. Variations in these indicators of interest then change the space of possibilities for the otherindicators.4 An example: suckler cattle farmingIn order to put this formalism into practice, a two-module model of suckler cattle farming (the "meat breeds")was constructed. The first module is that of crop production, the second that of animal production. These1The question of the threshold beyond which reconciliation becomes too important is one of the open problems.2Figure 1: Diagram of the material flow analysis for an existing socio-technical system.Note, for example, that sector E and product f are constrained by a material balance.two modules are closely linked: the main purpose of plant production is to feed the animals and the mainproduct of the animals, their excrement, is brought to the soil to fertilise it. This metabolism between farmanimals and the soil, which replaced the metabolism between humans, who were then low meat consumers,and the soil, is at the heart of some of the current problems in agriculture (opening up of the nitrogen [3],[4] and phosphorus cycles [5], competition between humans and animals for access to plant products [6], [7]).The two modules we have built are part of these debates. Taking up again what we developed in the section3, one of the questions we are trying to resolve is that of the incompatibility between certain organisationsof plant production and certain organisations of livestock.References[1] Jean-Yves Courtonne. Environmental assessment of territories through supply chain analysis: biophysicalaccounting for deliberative decision-aiding. PhD thesis, Université Grenoble Alpes, 2016.[2] Jean-Yves Courtonne, Julien Alapetite, Michela Bevione, Sylvain Caurla, Vincent Wawrzyniak, andYolande Ravaud. Af filières – analyse des flux des filières biomasse pour des stratégies régionales debioéconomie. rapport final. page 46, 2019.[3] Gilles Billen, Luis Lassaletta, and Josette Garnier. A vast range of opportunities for feeding the world in2050: trade-off between diet, n contamination and international trade. Environmental Research Letters,10(2):025001, 2015.[4] Gilles Billen, Julia Le Noë, and Josette Garnier. Two contrasted future scenarios for the french agro-foodsystem. Science of the Total Environment, 637:695–705, 2018.[5] Will Steffen, Katherine Richardson, Johan Rockström, Sarah E Cornell, Ingo Fetzer, Elena M Bennett,Reinette Biggs, Stephen R Carpenter, Wim De Vries, Cynthia A De Wit, et al. Planetary boundaries:Guiding human development on a changing planet. Science, 347(6223), 2015.[6] Sarah Laisse, René Baumont, Léonie Dusart, Didier Gaudré, Benoit Rouillé, Marc Benoit, Patrick Veysset,Didier Rémond, and Jean-Louis Peyraud. L’efficience nette de conversion des aliments par les animauxd’élevage: une nouvelle approche pour évaluer la contribution de l’élevage à l’alimentation humaine. 2019.3Figure 2: Material flow analysis scheme for a socio-technical alternative[7] Anne Mottet, Cees de Haan, Alessandra Falcucci, Giuseppe Tempio, Carolyn Opio, and Pierre Gerber.Livestock: On our plates or eating at our table? a new analysis of the feed/food debate. Global FoodSecurity, 14:1–8, 2017.4

Modular approach to material flow analysis

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Modular approach to material flow analysis

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