Maud Herbelin
email: maud.herbelin@eramet.com

Sylvain Delchini
email: s.delchini@brgm.fr

Henry Pillière
email: henry.pilliere@inelinnov.com

Luca Lutterotti
email: luca.lutterotti@unitn.it

Marion Nicco
email: marion.nicco@eramet.com

Moctar Dia
email: moctar.dia@eramet.com

Monique Le Guen
email: monique.le-guen@eramet.com

Thomas Riegler
email: thomas.riegler@eramet.com

Antonios Peppas

Christos Roumpos

Charalampos Vasilatos

Anthimos Xenidis

Mineral Composition of Heavy Mineral Sands Ores: Application of the New SOLSA Combined XRF-XRD Analytical Solution to the Grande Cote Operation Ti-Zr Mine

Keywords: coupled XRD-XRF analysis, quantitative analysis, heavy mineral sands, exploration

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Introduction

SOLSA (Sonic On-Line drilling and Sampling Analysis) is an ambitious project funded by the European Union that started in 2016. It delivered a prototype of a combined integrated sampling and analysis platform designed for use in the fields of mineral exploration, grade, and processes monitoring during operation [START_REF] Le Guen | Increasing exploration efficiency with SOLSA Expert System[END_REF] "https://solsa-dem-up.eu/en" (accessed on 3 November 2023). It aims to fast track and enhance ore body knowledge in order to facilitate the large-scale acquisition of the ore mineralogy and chemistry data needed to link ores to their processing characteristics. The goal is to provide an efficient tool for geometallurgy by quickly delivering, in the field, mineralogical and chemical analyses of drill cores or powdered samples, leading to the facilitation of fast exploration, mining, and processing decisions. In addition, better ore-knowledge allows for the anticipation of the mineralogy for both ore and gangue. It contributes to the anticipation and de-risking of new mining projects from the exploration stage through the integration of what could be the future life-of-mine mineral processing or corporate social responsibility (CSR) challenges.

Over the last 30 years, many instruments and approaches have been developed to provide the quantitative modal mineralogy of ore samples, e.g., [START_REF] Butcher | Advances in the quantification of gold deportment by QEMSCAN[END_REF][START_REF] Pirrie | Rapid quantitative mineral and phase analysis using automated scanning electron microscopy (QemSCAN); potential applications in forensic geoscience[END_REF]. Most of the techniques employ SEM-EDS-based technologies to identify and classify the particles based on their elemental composition. They are particularly useful for understanding deportment and liberation and allow for process modelling based on the properties of the particles such are size or density. However, it is always necessary to validate the calculated mineral proportions from the data processing software. In fact, calculations and mineral proportion interpretations are based on the chemistry and density of the minerals. Therefore, the calculated composition requires a cross validation by comparing to an independent bulk geochemical analysis using X-ray fluorescence or ICP-MS. Another approach is to back calculate the modal mineralogical composition from the bulk geochemical analyses using element-to-mineral (EML) conversion methodologies. While EML can be easily applied to large geochemical datasets, limitations arise from the difficulty to assign certain elements to the mineral phases that are present in the samples.

The example in this article is taken from Eramet's Grande Côte Operation (GCO) heavy mineral sands mine, in which primary detrital minerals, such as ilmenite, are subject to alteration, therefore producing a range of Fe and Ti-bearing minerals and are often accompanied by changes in oxidation state. Such mineral transformations in turn translate into different physical properties (e.g., magnetism) that could impact the methodologies used for their separation. With techniques based on the calculation and theoretical structural formulae of minerals, difficulties arise when the mineral phases of interest are impossible to differentiate based on their chemical composition alone. Polymorphs such as TiO 2 (anatase-brookite-rutile) have different physical properties [START_REF] Grant | Properties of rutile (titanium dioxide)[END_REF], hence different responses in the densimetric, magnetic, and electrostatic separation circuits of the ore processing plant. Researchers have already demonstrated the interest of using quantitative XRD for optimization and quality control during heavy mineral sands processing [START_REF] König | Heavy Mineral Sands Mining and Downstream Processing: Value of Mineralogical Monitoring Using XRD[END_REF].

The aim of the present work is to consolidate the validation of the data acquisition and signal processing procedures associated with SOLSA's benchtop analyser, thus, to evaluate the uncertainties and compare the quantitative results with established quantitative mineralogy based on Qemscan ® (Quantitative Evaluation of Minerals by Scanning electron microscopy) data. The advantages and limitations of the technique are discussed and replaced in the context of mass data acquisition procedures capable of feeding ore body knowledge with the geological and mineralogical data on which the geometallurgical models are based.

Materials and Methods

A Novel Coupled XRD and XRF Technique and Methodology

SOLSA's coupled analysis is a true combined approach to merging both XRD and XRF data acquisition and analysis. Custom analytical X-ray instrumentation (Figure 1) has been developed to perform the simultaneous data acquisition, by using a single X-ray source and dedicated detectors to collect the diffracted and fluorescent X-ray photons from the same sample volume. Additionally, a combined XRD/XRF data analysis methodology has been implemented by extending Rietveld-based code to incorporate the full pattern fitting of XRF spectra starting from the phases instead of a simple elemental composition matrix [START_REF] Bortolotti | Combining XRD and XRF analysis in one Rietveld-like fitting[END_REF].

Data Acquisition and Processing

XRF-XRD combined measurements were performed by the SOLSA combined instruments (Figures 1 and2) allowing for the simultaneous measurement of XRF and XRD signals. X-ray fluorescence spectra were acquired using a Mo micro-source radiation and an Amptek X-123 (AMPTEK INC, Bedford, MA, USA) SDD (Silicon Drift Detector) detector placed over the sample to ensure the measurement of lighter elements down to Z = 12 (Mg). Data were collected for a quantitative XRF model from 0.1 to 15 keV. X-ray powder diffraction data were acquired in asymmetric mode using Co Kα average radiation (Kα1 = 1.78900 Å and Kα2 = 1.79289 Å) and equipped with an INEL curved position sensitive detector which spans the entire 5 ≤ 2θ ≤ 120° range simultaneously. For this diffractometer, the instrumental function was also defined using yttrium oxide (Y2O3) standard powder following the analytical procedure described in [START_REF] Maestracci | Simultaneous combined XRF-XRD analysis of geological sample: New methodological approach for on-site analysis on New-Caledonian Ni-rich harzburgite[END_REF]. This instrument's configuration is accompanied by the use of a modular sample holder (Figure 1) capable of accommodating samples of different shapes, thus allowing the combined XRF-XRD analysis to be carried out on both prepared samples (e.g., a fine powder) and on samples with little or no preparation (e.g., coarse granulometric fractions, a cutting, a rock), as long as the surface to be analysed is flat.

Data Acquisition and Processing

XRF-XRD combined measurements were performed by the SOLSA combined instruments (Figures 1 and2) allowing for the simultaneous measurement of XRF and XRD signals. X-ray fluorescence spectra were acquired using a Mo micro-source radiation and an Amptek X-123 (AMPTEK INC, Bedford, MA, USA) SDD (Silicon Drift Detector) detector placed over the sample to ensure the measurement of lighter elements down to Z = 12 (Mg). Data were collected for a quantitative XRF model from 0.1 to 15 keV. X-ray powder diffraction data were acquired in asymmetric mode using Co Kα average radiation (Kα 1 = 1.78900 Å and K α2 = 1.79289 Å) and equipped with an INEL curved position sensitive detector which spans the entire 5 ≤ 2θ ≤ 120 • range simultaneously. For this diffractometer, the instrumental function was also defined using yttrium oxide (Y 2 O 3 ) standard powder following the analytical procedure described in [START_REF] Maestracci | Simultaneous combined XRF-XRD analysis of geological sample: New methodological approach for on-site analysis on New-Caledonian Ni-rich harzburgite[END_REF]. This instrument's configuration is accompanied by the use of a modular sample holder (Figure 1) capable of accommodating samples of different shapes, thus allowing the combined XRF-XRD analysis to be carried out on both prepared samples (e.g., a fine powder) and on samples with little or no preparation (e.g., coarse granulometric fractions, a cutting, a rock), as long as the surface to be analysed is flat.

Data Acquisition and Processing

XRF-XRD combined measurements were performed by the SOLSA combined instruments (Figures 1 and2) allowing for the simultaneous measurement of XRF and XRD signals. X-ray fluorescence spectra were acquired using a Mo micro-source radiation and an Amptek X-123 (AMPTEK INC, Bedford, MA, USA) SDD (Silicon Drift Detector) detector placed over the sample to ensure the measurement of lighter elements down to Z = 12 (Mg). Data were collected for a quantitative XRF model from 0.1 to 15 keV. X-ray powder diffraction data were acquired in asymmetric mode using Co Kα average radiation (Kα1 = 1.78900 Å and Kα2 = 1.79289 Å) and equipped with an INEL curved position sensitive detector which spans the entire 5 ≤ 2θ ≤ 120° range simultaneously. For this diffractometer, the instrumental function was also defined using yttrium oxide (Y2O3) standard powder following the analytical procedure described in [START_REF] Maestracci | Simultaneous combined XRF-XRD analysis of geological sample: New methodological approach for on-site analysis on New-Caledonian Ni-rich harzburgite[END_REF]. This instrument's configuration is accompanied by the use of a modular sample holder (Figure 1) capable of accommodating samples of different shapes, thus allowing the combined XRF-XRD analysis to be carried out on both prepared samples (e.g., a fine powder) and on samples with little or no preparation (e.g., coarse granulometric fractions, a cutting, a rock), as long as the surface to be analysed is flat. The combined XRF-XRD processing was performed using the LUXREM software v0 developed during the SOLSA project. The combined analysis method presented in Figure 2 is based on two powerful new approaches using state-of-the-art methodology. The first, Full Pattern Search Match (FPSM), searches for phases and chemical elements [START_REF] Lutterotti | Full-profile search-match by the Rietveld method[END_REF] using the Crystallography Open Database (COD) for mineral identification [START_REF] Gražulis | Crystallography Open Database (COD): An open-access collection of crystal structures and platform for world-wide collaboration[END_REF]. The second is used for the final quantification of the mineralogical crystal structure and chemical elements. It combines the Rietveld method for XRD fitting with a fundamental approach for XRF simulation in a unique algorithm refining both data simultaneously with a unique sample description [START_REF] Bortolotti | Combining XRD and XRF analysis in one Rietveld-like fitting[END_REF].

This permits the most accurate description of the physics and eliminates the approximations used in the separated approaches. It can also estimate light elements, such as Li, O, C, etc., which are not quantifiable by standard XRF in air or under gas.

SEM-EDS-Based Automated Mineralogy

SEM-EDS-based automated mineralogy analyses were performed on polished sections using the QEMSCAN ® system at Eramet Ideas. Acquisitions were made on an FEI Quanta 650F SEM platform with two Bruker Xflash 30 mm 2 silicon drift energy dispersive spectrometer X-ray detectors. The iMeasure v. 5.2 software was used for data acquisition and iDiscover v. 5.2 software was used for spectral interpretation and data processing. The PMA (Particle Mineral Analysis) measurement mode was used to collect X-ray data every 2.5 µm across the surfaces of the polished sections, with a total of 2000 counts per spectrum.

Samples

Table 1 provides information on the sample preparation and analytical techniques used to characterize and quantify the geochemistry and mineralogy of the samples.

Results

The intrinsic strength of the coupled XRD/XRF methodology is the mutual re-enforcement during data processing, where the chemistry helps refine mineral proportions and vice versa. A comparative approach using well established techniques for both elemental and mineral quantification allows for the comparison of the performance and quality of the data and signal processing obtained with the SOLSA system and the LUXREM data reduction software. It must be noted that there is no per se mineral quantification standard. The standard method for the QA/QC of the mineral proportion with Qemscan ® is performed with respect to the fused-bead XRF geochemical analysis and the recalculated assay generated from the mineralogical data base.

3.1. Chemical Quantification: SOLSA vs. Fused-Bead WD-XRF Figure 3A, presents the distribution of the same samples analysed using conventional fused-bead XRF as well as SOLSA XRF. This provides a preliminary assessment of the data generated from the SOLSA equipment for both milled and as-is samples at the natural size distribution of the mineral grains forming the concentrate, with the only exception being the AMIS reference materials, which were received already milled. The 1:1 black line represents the ideal reconciliation between the two methods. These preliminary results indicate that both light and heavier elements tend to be quantified within the same order of magnitude with respect to the reference method by WD-XRF. Most datapoints fall below a 10% relative error and only a few have relative errors of around 40 to 50%. Investigation is still ongoing to better understand the outliers. In fact, the same elements were successfully measured with high accuracy relative to the reference values obtained by WD-XRF on aliquots of the same sample.

Mater. Proc. 2023, 15, 41 FOR PEER REVIEW 5 of is performed with respect to the fused-bead XRF geochemical analysis and the recalcu lated assay generated from the mineralogical data base.

Chemical Quantification: SOLSA vs. Fused-Bead WD-XRF

Figure 3A, presents the distribution of the same samples analysed using conventiona fused-bead XRF as well as SOLSA XRF. This provides a preliminary assessment of th data generated from the SOLSA equipment for both milled and as-is samples at the natu ral size distribution of the mineral grains forming the concentrate, with the only exception being the AMIS reference materials, which were received already milled. The 1:1 black line represents the ideal reconciliation between the two methods. These preliminary re sults indicate that both light and heavier elements tend to be quantified within the sam order of magnitude with respect to the reference method by WD-XRF. Most datapoint fall below a 10% relative error and only a few have relative errors of around 40 to 50% Investigation is still ongoing to better understand the outliers. In fact, the same element were successfully measured with high accuracy relative to the reference values obtained by WD-XRF on aliquots of the same sample.

Mineral Quantification, SOLSA Coupled XRD-XRF vs. Qemscan ®

Mineral proportions calculated with the SOLSA equipment are presenting a good agreement with mineral proportion calculation from Qemscan ® with a distribution of th datapoints near the 1:1 line representing the ideal reconciliation (Figure 3B). Discrepancie between the two methods were anticipated due to the use of two different databases, on using the chemical composition of the pixels, while the other using the crystallographi and fundamental properties of physics to perform advanced Rietveld processing. The dif ferences between TiO2 polymorphs quantification could provide an understanding of how minerals would be reported in the different mineral separation circuits of the mine pro cessing plant. In addition, mineralogical investigation at the crystal scale with SOLSA might provide a better methodology to understand ilmenite alteration and the subsequen consequences it might have on its separability using high intensity magnetic fields. Both methods provide a similar mineralogical assemblage of the samples providing good con fidence that the technique could soon be integrated with other mineralogical and geo chemical datasets in use at the mine. 3.2. Mineral Quantification, SOLSA Coupled XRD-XRF vs. Qemscan ® Mineral proportions calculated with the SOLSA equipment are presenting a good agreement with mineral proportion calculation from Qemscan ® with a distribution of the datapoints near the 1:1 line representing the ideal reconciliation (Figure 3B). Discrepancies between the two methods were anticipated due to the use of two different databases, one using the chemical composition of the pixels, while the other using the crystallographic and fundamental properties of physics to perform advanced Rietveld processing. The differences between TiO 2 polymorphs quantification could provide an understanding of how minerals would be reported in the different mineral separation circuits of the mine processing plant. In addition, mineralogical investigation at the crystal scale with SOLSA might provide a better methodology to understand ilmenite alteration and the subsequent consequences it might have on its separability using high intensity magnetic fields. Both methods provide a similar mineralogical assemblage of the samples providing good confidence that the technique could soon be integrated with other mineralogical and geochemical datasets in use at the mine.

Concluding Remarks

These are the first preliminary results obtained with coupled XRD-XRF on a reallife practical case of mineral processing optimization at the GCO mine in Senegal. The combined instrument demonstrates its potential to acquire mineralogical and chemical data simultaneously from the same sample. Results could be further improved by database adjustments to better fit the signals or sample preparation procedures, while the counting time of the acquisitions could also be increased to improve statistics.

The acquisition of signals from various types of powder materials, either mill or as-is with different particle size distributions, allowed for the testing of these effects on both the acquisition and processing of the signals coming from the combined instruments. It also contributed to the creation of a site-specific mineralogical database for heavy mineral sands.

Further work will include the full development of a QA/QC procedure for both the mineralogy and the chemistry. These first XRD results also evidenced the already known difficulties of powder measurements [START_REF]Crystal Structures of Clay Minerals and Their X-ray Identification[END_REF]. However, the ongoing expansion of the test sample set could contribute to the better consideration of the factors influencing the accuracy of the measurements and the implementation of hardware and software mitigating actions. In parallel the ability to test the mineralogy of the different commercial products in the mine will potentially provide means to improve the recovery of the minerals of interest and better anticipate the yield of the commercial products thanks to better control of the mineralogy. One of the other strengths of the method compared to traditional SEM-based mineral quantification instruments is looking at the mineral transformation at the scale of the crystals forming the minerals. This enables the quantification of mineral phase transformation at a sub-micron scale, a common feature in the alteration of minerals in natural environments, as well as in many extractive metallurgy processes. The application of the combined mineralogical and geochemical data could have multiple uses throughout the life-of-mine cycle, from mineral exploration to the environmental monitoring of industrial wastes.

Figure 1 .

 1 Figure 1. Schematic representation of the combined XRD-XRF acquisition platform as well as the signal generated simultaneously on both detectors. On the left, the sample holder and position of the detectors, and on the right, example of an acquisition. Modified from [7].

Figure 1 .

 1 Figure 1. Schematic representation of the combined XRD-XRF acquisition platform as well as the signal generated simultaneously on both detectors. On the left, the sample holder and position of the detectors, and on the right, example of an acquisition. Modified from [7].

7 Figure 1 .

 71 Figure 1. Schematic representation of the combined XRD-XRF acquisition platform as well as the signal generated simultaneously on both detectors. On the left, the sample holder and position of the detectors, and on the right, example of an acquisition. Modified from [7].

Figure 2 .

 2 Figure 2. Schematic representation of the combined XRD-XRF processing method based first on mineral and chemical element identification (Full Pattern Search Match, FPSM), and then on combined mineralogical and chemical quantification (Rietveld quantification).

Figure 3 .

 3 Figure 3. (A) Powder EDXRF from SOLSA vs. fused-bead WD-XRF for milled and as-is all sample on some of the key elements of interest present in the heavy mineral concentrate and reference ma terials. (B) Mineral proportions calculated by the LUXREM software and compared to the minera proportion quantification obtain by Qemscan ® .

Figure 3 .

 3 Figure 3. (A) Powder EDXRF from SOLSA vs. fused-bead WD-XRF for milled and as-is all samples on some of the key elements of interest present in the heavy mineral concentrate and reference materials. (B) Mineral proportions calculated by the LUXREM software and compared to the mineral proportion quantification obtain by Qemscan ® .

Table 1 .

 1 Sample list including standard reference material provided by the GCO mine: AMIS0616

		(rutile); AMIS0697 (ilmenite, Kenya) and AMIS0454 (ilmenite, Tronox Mineral Sands (Namakwa Sands
		Mines); as well as pure commercial products representing different types of mineral concentrates
		with contrasted mineralogical compositions.
	Sample	(Milled)	(As-Is)	Mineralogy	Geochemistry	SOLSA Coupled XRD-XRF Analysis
	Rutile concentrate	yes	yes	Qemscan ®	WD-XRF	yes
	Ilmenite concentrate	yes	yes	Qemscan ®	WD-XRF	yes
	Zircon concentrate	no	yes	Qemscan ®	WD-XRF	yes
	AMIS0697	yes	no	Certificate	Certificate	yes
	AMIS0454	yes	no	no	Certificate	yes
	AMIS0616	yes	no	Certificate	Certificate	yes
	Conc 1	yes	yes	Qemscan ®	WD-XRF	yes
	Conc 2	yes	no	Qemscan ®	WD-XRF	yes

Mater. Proc. 2023, 15, 41. https://doi.org/10.3390/materproc2023015041 https://www.mdpi.com/journal/materproc

Data Availability Statement:

The data presented in this study are available on request from the corresponding author.


The value of the Negawatt: load-shifting electricity consumption

Thomas Reverdy

Published in Goulet Frederic, Vinck Dominique, 2023, New horizons for innovation studies. Doing without, doing with less, Edward Elgar Publishing Most energy transition experts agree that it will not be possible to achieve objectives of climate and intermittent renewable energy development without transforming electricity consumption patterns towards more sober and flexible practices. The neologism Negawatt embodies the idea that "nonconsumption" of electricity could be made equivalent to production of electricity: one megawatt of electricity not consumed is equivalent to one megawatt of electricity produced.

This equivalence is a powerful idea that is frequently mentioned in the public debate on saving energy, and would be preferable to building new nuclear power stations or using polluting production units involving gas or coal. Possibilities of not consuming are a potential source to be exploited, quantifying the energy that does not have to be produced. This equivalence between non-consumption and production creates an unexpected association between the act of consumption and the act of production, whereby the consumer who does not consume becomes a sort of producer since, by not consuming, they make available the electricity they should have consumed. This idea has also been embraced by those concerned about how to guarantee the balance between production and consumption in real time in the electricity network. Since electricity is not easily stored, a targeted effort to reduce consumption can be particularly useful in periods when production resources are insufficient. The potential for reducing consumption guided the design of the "peak day load shifting" tariff by EDF (Électricité de France) in the 1980s to relieve consumption peaks in winter. It also prompted the creation of a new activity that can be carried out by an economic actor independent of the supplier, namely a load-shifting aggregator, which, by various technical means, arranges the modulation of consumption by a group of consumers. As soon as this activity is taken over by an economic operator independent of a supplier, the question arises as to its economic value. Is "non-consumption" equivalent to a production activity, as the word Negawatt suggests? Does it have the same value? Should the aggregator be remunerated like an electricity producer? Without neglecting the design and implementation of new infrastructures and organizations, this chapter focuses on one aspect of the transformations at stake, namely the regulatory processes that support the construction of a technical and economic equivalence between 'non-consumption' and electricity production.

This regulation was first discussed by a technical committee led by the Transportation System Operator (TSO), on the initiative of Pierre Bivas, one of the founders of Voltalis, an aggregator of load shifting for individual consumers. Said regulatory work was necessary to link this new activity to the electricity market, which, in the context of the liberalization of the sector, has been in charge of electricity exchanges and the balance of the network. In other words, it was a question of drawing up the rules to allow an economic value to be attributed to temporary "non-consumption", as required by the network to cope with the disequilibrium between production and consumption. Dissatisfied with the proposals of the TSO and subsequently the ERC (Commission de régulation de l'énergie, or Energy Regulatory Commission), which regulated the sector, Bivas requested political arbitration and called on the legislative in an attempt to improve remuneration for this activity.

Unlike the other innovative approaches discussed in this book, encouraging frugal behaviour or the renunciation of consumption does not involve any effort to simplify techniques or achieve greater sobriety in economic organization, or regulation. The choice of using economic tools to encourage the organization of consumer load shifting implies investing in the design of a new, complex regulation that complements the existing one.

Moreover, the technical-economic reasoning that attempts to assess the nature of saving behaviours to evaluate their various effects and assign a value to these is particularly sophisticated. To justify their regulatory proposals, the promoters of these practices simplify these arguments, as the neologism Negawatt invites them to do. Thus, by looking closely at these policies of economy or substitution, we are prompted to consider the different deliberation processes and the constraints on the validity of the technical-economic rationale underpinning new regulations.

The balance of the network between the production and consumption of electricity

Describing the power system as a whole helps us to understand the role of flexible electricity consumption. Since 2000, electricity generation in France has been gradually opened to competition, included new producers and suppliers, and been integrated into the European wholesale market. Generation operators sell electricity on the wholesale market and to end customers through local distributors and alternative suppliers. The transmission and distribution networks remain monopolies.

As electricity cannot be stored, the entire electrical system must guarantee a real-time balance in a setting of variable consumption, which depends on consumer activities and weather conditions. Furthermore, the supply itself is variable due to equipment failure or the intermittent production of renewable energies such as wind or solar power. The TSO physically organizes electricity exchanges at the national level so that the balance between production and consumption is guaranteed. To cope with variations, suppliers or the TSO resort to sufficiently flexible capacities, such as hydro or gas power plants. Certain power plants are only used for a few hours a year but still require permanent maintenance so that they may be activated at any time. Some of the are fossil-fired power plants, which entail very high financial costs and serious environmental effects (CO2 emissions).

Consumer load shifting is an alternative to the use of these flexible production resources. It was developed for industrial consumers whose downtime allows for the availability of significant power. Before liberalization, large electricity consumers already resorted to this option to work towards a better balance of the network. They benefited from a privileged tariff taking into account this service.

The company Voltalis, created in 2006, organizes load shifting for end users, administration and small companies and businesses. This is referred to as "distributed load shifting". Using a remote-controlled electronic box, Voltalis can cut off the power supply to various electronic devices in a consumer's home (individuals or craftsmen, SMEs) for short periods. By installing its box, the company can make available a sufficient quantity of electricity to be taken into account by the TSO. Voltalis has chosen not to remunerate the consumers for their participation, which has the advantage of reducing the cost for the company. However, this choice implies that the load shifting should only marginally affect the convenience of using electricity, by limiting the equipment concerned (e.g. heating or water heaters) and the duration of the load shifting (½ hour). The cost of manufacturing, installing a box is around 500 euros for a power of 1 or 2 kW. The first advantage of the Voltalis box is that it can guarantee the TSO a capacity for reducing the load in a short period because it is the company, not the consumer, that automatically orders the reduction. The decrease in consumption is thus associated with Voltalis' action rather than a change in the individual's consumption practices.

Valuing distributed load shifting: converting a reduction into production

In a liberalized electricity sector, the balance between production and consumption is ensured by several mechanisms. Firstly, each supplier is responsible for the balance, i.e. they must supply the network with the same quantity of electricity as their customers consume. If they do not have this electricity, they can obtain it on the wholesale electricity market, which operates on an auction mechanism; this aggregates all offers and demands and, by setting a market price, ensures a balance between supply and demand. This auction is established from one day to the next, based on forecasts. In addition, there is a mechanism for managing the differences between forecasts and what is produced and consumed in real time. This is the balancing mechanism, which also operates as a market and allows the TSO to cover divergences from forecasts by buying and selling electricity in real time.

Large industrial consumers have been quick to seize the opportunity to enhance their flexibility by reducing consumption when the market price is high and reselling the electricity purchased but not consumed. They can join forces with load-shifting aggregators to manage this resale of electricity. Industrial consumers use this option when the market price is very high, specifically when the difference between the market price and the price set out in their supply contract is greater than the losses that would be incurred by a drop in production.

In dialogue with Voltalis, the TSO planned to include load shifting end users in the balancing mechanism in 2007. This inclusion required an experiment (which was limited to 100 MW) to clarify its implications for the various market operators. To lay down the transitional rules for implementing load shifting, numerous exchanges took place in 2007 between the TSO, the ERC, Voltalis and other players in the sector, through a working group called GT Effacements Diffus (Distributed Load-Shifting Working Group), set up by the TSO. The new proposal was taken seriously by the ERC and TSO, which both wished to encourage flexible consumption. Similar initiatives were observed in many other European countries (Pallesen and Jenle, 2018).

The TSO and ERC engineers in charge of designing how the market will work normally proceed through in-depth technical discussions where the stakeholders express their requirements, to which the TSO responds by raising concerns related to efficiency and economic relevance within the framework of the technical solutions available. Decisions are generally discussed by the participants, who each represent their company. Collective decision making is facilitated by the exchange of technical arguments; the participants, who are largely engineers or economists, are keen to defend technically and economically valid arguments to maintain their credibility.

In the opinion of several observers, the debate on distributed load shifting had taken a different turn from the usual discussions. During 2008, the stakeholders were unable to reach an agreement on the financial transfers resulting from the activation of load shifting. The disagreement put Pierre Bivas, founder of Voltalis, at loggerheads with the electricity suppliers, including EDF, over whether the loadshifting aggregator should pay the suppliers for the "shed" electricity.

The conditions for equivalence between load shifting and electricity generation

In the absence of a consensus, the TSO asked the ERC to clarify the rules. The ERC's engineers and economists sought to define a method of integrating the activity as "cleanly as possible". They asked Claude Crampes, an economist from the Toulouse School of Economics, to check the validity of their economic reasoning. The ERC published a deliberation1 in which it explained and justified the payment for the electricity shifted to the supplier by the load-shifting aggregator.

The ERC pointed out that the balancing mechanism is essentially based on a market mechanism. It is brought into action by the TSO when one of the supplier (A) fails to produce the electricity to which it has committed or if it fails to satisfy its consumers. Then, on the balancing market, the TSO chooses between offers from producers (with additional capacity) and those from load-shifting operators to restore the balance. By going through this "market", the TSO is not only buying a service that contributes to restoring the balance of the network, but it is also buying electricity that is then sold to the supplier (A), who has failed and who needs it for its consumers. The only way for the load-shifting aggregator to participate in the balancing mechanism is therefore to sell electricity and not simply shift the load. However, the load-shifting operator does not produce electricity; it obtains it from a supplier (B) which had agreed to supply it to its customers (as part of its balancing responsibility) but the energy has not been consumed by the latter. It would seem logical that the load-shifting aggregator should pay the supplier (B) for this electricity that the latter has injected, at least at the level of the supply price (which the customers would have paid it if they had not been shed).

Giving value to diffuse load shifting means converting it into a resource that can be attributed with a value on the market, i.e. an electricity supply. The ERC modelled the circulation of electricity within a framework shared by all stakeholders, that of the electricity market and, more specifically, the balancing mechanism. In this model, the possibility of attaching monetary value to the load-shifting service assumes that an equivalent quantity of electricity has been produced and that the cost of this production is compensated by the load-shifting aggregator. The aggregator's offer must take into account the costs incurred in producing the electricity it supplies to the balancing mechanism.

Echoes of simplified reasoning: journalists and government

During the workshops held at the TSO and then at the ERC, Bivas vigorously contested the technical and economic reasoning put forward by the experts. He proposed another conceptualization of the contribution of load shifting, which considered that, in a situation of imbalance between production and consumption, the TSO's alternative was either to request additional production equipment or to call for load shifting from consumers. He considered that, from the point of view of the network, the two solutions are equivalent and can be directly compared. The criterion of economic precedence, explained in law, must be applied when comparing these two types of offer. In this context, the payment to suppliers has no reason to exist.

Maintaining this economic reasoning, Bivas challenged the preliminary framework introduced by the TSO and the ERC, in other words, the fact that the balancing mechanism was based on an electricity market. In Bivas' argument, the aggregator did not seek to sell electricity but only load shifting. His reasoning was free of the rules introduced by the balancing mechanism, such as the suppliers' balancing responsibility.

It was more accessible than the ERC's reasoning and corresponded more to a technical understanding of the problem of the supply-demand balance on the network. Because of its relative simplicity, Bivas' argument seemed less susceptible to manipulation or bias. Furthermore, he referred to the equivalence between the Negawatt and the Megawatt: from the angle of grid balance, these solutions are equivalent.

According to the members of the ERC and TSO interviewed for this article, Bivas' argument restricted the scope of attaching economic value to the alternatives, namely producing or load shifting. It took into account only the balance of the network and did not consider the supply of electricity to consumers, also provided by the network. When an electricity producer contributes to the balance of the grid, it also allows a consumer to consume electricity, whereas the load-shifting aggregator does not. These two solutions may be equivalent from the point of view of grid balance, but they do not offer the same economic value to the electricity system as a whole.

Challenged within the technical arena, Bivas sought to move the confrontation into media and political circles. He did not hesitate to draw on his background as a polytechnicien, as a member of the prestigious Corps des Mines, and as technical adviser to several ministerial cabinets. His argumentative strategy consisted of defending his definition of the contribution of load shifting to the balance of the network, and the equivalence of load shifting with electricity production.

Once his audience had accepted this initial framing, he could criticize the requirement to pay suppliers compensation for electricity not consumed by their customers. In his proposed framing, this payment could be presented as compensation for energy that was not consumed and therefore not produced. The denunciation of the payment to suppliers was further combined with an environmental argument that associated load shifting with an action to reduce consumption, an action with a positive political value, in line with political objectives. Voltalis' equipment would enable EDF to avoid the use of "expensive and polluting fossil fuel power stations" 2 . The French green party, Europe Écologie les Verts, and the antinuclear association, Sortir du Nucléaire, readily agreed with this argument, which was in line with their denunciation of EDF's dominant position on nuclear power. Payment to suppliers was described in their position papers as an "organized racket", and a "bonus for energy waste" 3 .

It should be remembered that, in the context of the balancing mechanism as designed by the TSO, the payment to the supplier concerns electricity that the supplier has committed to supply as part of its balancing responsibility. This is energy that it has produced and needs to be valued by the aggregator on the balancing market. Bivas' argumentative strategy consisted of integrating the payment to suppliers not in the definition of the balancing mechanism provided for by TSO, but in its own definition of the balancing mechanism. This argumentation allowed this payment to be shown as an unjustified compensation for suppliers. This argumentation widely circulated among stakeholders and political representatives and had contributed to the ERC's loss of credibility.

2 Press release published in 2009 by Voltalis : Comment EDF a circonvenu la CRE en lui faisant adopter le point de vue des fournisseurs au détriment des consommateurs, donc préférer toujours plus de production, à une économie d'énergie et renforcer la position dominante d'EDF en France (How EDF circumvented the ERC by making it adopt suppliers' point of view at the expense of consumers, therefore preferring ever greater production to energy savings and reinforcing EDF's dominant position in France) 3 Europe Ecologie les Verts (2009, 07 20). EDF veut faire payer les économies d'énergie à ses clients (EDF wants to make its customers pay for energy savings)

In particular, the expression "manque à gagner" (loss of earnings) was very frequently cited by Voltalis and relayed by the interlocutors: "This means that, if a group of EDF customers agrees to reduce their consumption, EDF demands to be paid as if they had consumed"4 . The way of presenting the payment to suppliers, i.e. as compensation for a loss of earnings, was so successful that Bivas continued to use it in all his communication. The use of the expression "manque à gagner" to refer to the suppliers' losses was particularly ingenious, as it could have two meanings. For the ERC, in the balancing mechanism defined by the TSO, it was a financial loss linked to the fact that the supplier with balancing responsibility had produced electricity and had not been remunerated for it. As Bivas did not present the balancing mechanism as a whole, "manque à gagner" could be put forward as a simple loss of turnover. However, for the audience, this loss in turnover should not be compensated. It does not seem legitimate to pay a supplier for electricity that it has not produced.

The media success of Voltalis' argument was also due to the fact that the company embodied an ambition that nobody disputed. For the majority of politicians interested in energy issues, it was imperative to develop the modulation of consumption. Voltalis, the only company to offer a tangible solution, was particularly well received. Moreover, following this highly publicized debate, it had acquired legitimacy in the political arena. The support of Jean Louis Borloo and Europe Écologie Les Verts gave Voltalis a legitimacy that it did not have in the technical sphere of the balancing mechanism, where economic expertise prevails.

Throughout this period, EDF was completely absent from the media. Our interviews with members of the ministry, the TSO, and the ERC, and with EDF's regulatory experts, show that the company did not wish to expose itself in the debate. EDF refused to comment on the ERC's decisions and challenge Bivas' discourse. EDF representatives were also very concerned about their lack of legitimacy in the public debate and did not wish to risk weakening the ERC's position by taking a stance.

The main result of this media coverage was the involvement of political representatives in the technical deliberations. On 22 July 2009, Jean Louis Borloo, then Minister of State, and Minister for Ecology, Energy, Sustainable Development and Town and Country Planning, denounced "the existence of legal and financial obstacles to the development of innovative energy-saving offers". The Minister said he wanted to remedy this situation and announced the establishment of a new working group.

The controversy caused by Bivas and the political support he received encouraged him to appeal to the Council of State. On 3 May 2011, the Council of State5 censured the ERC's decision of 9 July 2009. The Council of State did not challenge the economic reasoning of the ERC, but it did challenge its right to establish a new obligation for the aggregator, based on the economic grounds that the controversy had weakened. The Council of State criticized the ERC for using an abstract representation of load shifting, in other words a definition of the exchanges carried out on said market, which was not in the law.

The Council of State's decision allowed Bivas to defend his arguments in several press articles. In the wake of this decision, Voltalis continued to be remunerated by the balancing mechanism each time it activated load shifting, without having to remunerate the suppliers whose customers had been shed. Voltalis then sold the electricity that the suppliers of load-shifted customers had produced as part of their balancing responsibility. According to the interviewed members of the TSO and ERC, without remunerating the suppliers, the mechanism created a significant windfall effect, as the load-shifting aggregator has tended to activate activating load shifting as frequently as possible and in all circumstances to meet balancing needs. In addition to the windfall effect, frequent load shifting created disturbances in consumption in the homes concerned. Load shifting also resulted in a postponement of consumption. Immediately after load shifting, there was an increase in consumption as the heating system or boiler were run at full power after having been switched off, to recover the temperature set by the thermostats.

Influence strategy: misuse of the notion of injected electricity

Following the elections in June 2012, with a socialist majority in the National Assembly, the energy issue was by François Brottes, a Member of Parliament who showed little interest in Voltalis' project. Brottes Law of 16 April 2013 supported the ERC's reasoning and imposed a payment to suppliers for "injected electricity".

Voltalis nevertheless obtained from Ségolène Royal, Minister for the Environment, the introduction of a premium that integrated all the socio-economic benefits. The calculation of the premium was delegated to the ERC, which identified some benefits in terms of reduced energy consumption; however the premium did not ensure that the activity was profitable. Voltalis looked for other sources of remuneration by participating in the capacity mechanism, a complementary mechanism to the electricity market that guaranteed the security of the network in the event of peak consumption. It was allowed to participate in capacity tenders at the same level as electricity production facilities.

However, the question of payment to the suppliers reappeared during the drafting of the bill on energy transition planned for 2015. During discussions on this bill, the obligation to pay suppliers was amended by Brottes. This amendment provided for a difference between the energy saved during load shifting and the energy whose consumption was postponed until after the load-shifting period. It proposed that the load-shifting aggregator should only pay the supplier for electricity whose consumption has been reported. The justification for this amendment was based on a definition of "injected electricity" that was entirely consistent with the reasoning of Bivas and not with the original rationale of the 2013 Brottes law. It was written: "This amendment aims to clarify the notion of load shifting by distinguishing from other types of load shifting the "definitive" load shifting, which is not followed by a rebound effect and which is not covered by self-generation. Since this type of load shifting produces real energy saving, it is not justified for the load-shifting operator to pay a premium to the supplier, insofar as the latter will not have to supply electricity afterwards."6 Thus, this amendment gave a new interpretation to the notion of "injected electricity". It associated the notion of "injected electricity" with the additional electricity injected for the postponement of consumption, whereas, in Brottes' law, this "injected electricity" was considered to be the necessary condition for the aggregator to participate in the balancing mechanism. The rebound effect does lead to an injection of electricity, but this effect is nevertheless assumed by the suppliers as part of their balancing responsibility. They sell the electricity to the consumers on this occasion.

Most of the players involved in regulation noted this semantic shift, which called into question all the formalizing and clarifying efforts previously made by the TSO and the ERC. The main drafter of the law explained in an interview that, following the 2013 Brottes law, Bivas' discourse had clearly resonated with parliamentarians and Minister Ségolène Royal. According to the drafter, the ERC's reasoning had not been understood by parliamentarians and, as a result, the notion of "injected electricity" as defined in the previous law was not understood. For the parliamentarians, "injected electricity" referred solely to the postponed consumption. The MPs did not understand why the supplier should be paid for the part of the load shifting that had not been carried over, i.e. the electricity saved. The amendment also made it possible to provide additional funding for load shifting and at the same time satisfy the parliamentarians: if consumption is postponed, a payment to the supplier seems legitimate; if it is saved, and therefore not produced, the suppliers must manage to finance it by themselves.

Nevertheless, some members of the ministry and the ERC were concerned about the potential accumulation of funding for load shifting (following this new amendment coming from the premium and the capacity mechanism. In a favourable economic context, this accumulation could create a significant windfall effect. Such a situation of excessive remuneration had occurred in the past (in the support mechanisms for renewable energies) and these stakeholders had had great difficulty changing such overly favourable regulations. Some of them had shared their concerns with the consumer protection association, UFC-Que Choisir, which had filed a complaint with the Council of State against the premium: "This premium is scandalous (...), there is no general interest being pursued. This subsidy creates a risk of over-remuneration of capital since it pays for the electricity that the load-shifting operator sells on the markets. This risks creating unreasonable margins. They are creating an approximate system based on special interests."7 Consumer associations had been particularly critical of load shifting, which was presented as a practice that simply turns off heating equipment automatically for 20 minutes when consumers need it most.

During the examination of the text in the parliamentary commission, several amendments in favour of distributed load shifting were proposed by opposition parliamentarians, who claimed that the government and majority parliamentarians were playing into EDF's hands. They also accused the government of modifying the text between the Senate and the Assembly. Conversely, the ecologist MPs expressed doubts about the actual energy savings obtained with diffuse load shifting. Had they simply read the articles published by consumer associations or the Médiapart website, or had they been approached by representatives of the ERC or EDF? The parliamentarians had difficulty explaining their position at the first sign of contradiction or criticism and accused each other of being manipulated by company lobbyists. The confusion of the debates encouraged Brottes to hold a meeting with EDF and Voltalis for a more direct confrontation of the technical and economic arguments.

The legislation passed by parliament following a new legislative reading on 26 May 2015 showed a decline in Voltalis' influence. The accumulated doubts and the virulence of the debates had encouraged Brottes to rely more on the ministry, which had become increasingly convinced of the need for greater caution in the design of the mechanism. The direct confrontation between the representatives of EDF and Voltalis had also enabled him to better understand the reasoning of the various protagonists. Thus, Article 46 bis clarifies the need for payment to a supplier whose customers have been load shed, taking up the arguments put forward by the ERC in its first statement. Nonetheless, the law required that this payment be shared between the load-shifting aggregator (for the postponed amount of electricity and all suppliers (for the saved amount of electricity). It incorporated elements from the parliamentary debate and the amendment inspired by Voltalis. The law also made it possible to improve Voltalis' remuneration by adding to the payment for the service provided to the network, a remuneration equivalent to the electricity saved. Although the initial idea of a distinction between "saved electricity" and "postponed electricity" originated from a misunderstanding of the notion of "injected electricity", this distinction made it possible to introduce additional support for distributed load shifting into the mechanism whenever such shifting contributed to reducing consumption. The ERC pointed out to the legal drafter the difficulty of applying such a rule, but this point was not followed up.

By switching to the media and political arenas, the rigorous requirements that prevailed within the workgroups organized by the TSO and the ERC, such as the requirements for confrontation between the arguments, were no longer guaranteed. While parliamentary deliberation offered the possibility of taking political issues into account in regulation, it also had obvious weaknesses in terms of technical depth. Media and parliamentary debates allowed for approximations and reinterpretations of technical concepts, without the intervention of technical experts. The mechanism was eventually finalized following informal confrontations, held as a last resort and behind closed doors, while it was dogged with legacy of the misunderstandings of the parliamentary debate.

For many of the actors interviewed, the development of this regulation is emblematic of an institutional set-up built on a distinction between technical and political deliberation, but which fails to maintain this separation. The system places elected officials in a weak position in the face of technical complexity as they are unable to identify the weaknesses in the reasoning of the various stakeholders, the implicit hypotheses and the perimeters considered, while the various representations of economic mechanisms are oversimplified.

Designing incentive policy: an exercise in technical democracy

Policies that aim to encourage a partial reduction (not abandonment) of activity, for reasons of resource conservation or limited capacity, are sometimes the subject of incentive actions by public authorities. These may take the form of subsidies for energy reduction investments or the financial valuation of avoided CO2 emissions or saved energy, among others. Encouraging a reduction in consumption is much more complex than prohibiting the circulation or use of a product. The simplest tool remains taxation on the use of a resource or activity but the disadvantage of this tool is that it results in highly punitive financial transfers; hence the development of incentive policies by remunerating the practice of reducing or giving up consumption. These policies pose new challenges for public authorities and political decision makers in terms of designing incentive instruments, avoiding windfall effects and evaluating direct and indirect repercussions. Political authorities need to clearly understand each situation and how the instruments work, which can sometimes involve complex modelling and fragile assumptions (MacKenzie, 2008).

However, modelling efforts are generally based on a characterization of this 'reduction' (in consumption or emissions) employing counterfactual reasoning that compares situations with or without the reduction effort (Ehrenstein and Muniesa, 2013;Lohmann, 2009). They are likewise based on a delimitation of effects and on usage. In many cases, these models are controversial, often because they do not take into account certain indirect effects, which are not assessed at the same level by different observers. This was the case for many CO2 emission reduction projects under the Kyoto Protocol's Clean Development Mechanism, which requires a comparison of projects with a counterfactual situation (i.e. the same project without the support) in order for the applicant to receive emission credits. Sometimes, the balance of an emission-reducing action completely changes with the identification of an external condition that was previously neglected, such as the issue of land use when promoting the substitution of fossil fuels with biomass fuels (Boucher, 2012;Doganova and Laurent, 2016;Laurent, 2015). Counterfactual reasoning to establish a reduction in CO2 emissions can also be challenged by the definition of the scope of the comparison, which may or may not be considered negligible.

Drawing up these incentive policies is therefore both technical, due to their complexity, and political, in view of the many underlying hypotheses concerning the economic valuation of environmental effects, the definition of reference situations, and the choice of perimeters, among other factors. As shown with the example of distributed load shifting, the fine-tuning of the instrument requires time and effort in the representation and modelling, generally undertaken in 'technical' bodies such as the regulatory authorities. It also involves deliberation within political bodies, which allows for the integration of more parameters and indirect effects than can be handled by the technical bodies. Deliberation moves from one space to another, which means that the technical models, which are sometimes counter-intuitive, can be understood by stakeholders in spheres of political deliberation, in particular the elected representatives. Conversely, political requirements are taken into account in the technical development. Each body tries to intervene by adding additional rules or, on the contrary, simplifying the rules or mechanisms, at the risk of losing rigour or neglecting political expectations.

The equivalence between consumption reduction and production activity, inherent in the term Negawatt, was taken up by Voltalis to construct and communicate its representation of the contribution of diffuse load-shifting aggregation. It was confronted with another representation, advocated by the regulators, namely to convert "non-consumption" into an effective contribution to the network balance. The TSO and the ERC have adhered to the institutional framework in force, which considers that the network balance is ensured by a supply-demand market balance. To include load shifting in this market, they have used an abstract model of load shifting, in the form of a flow of electricity from the load-shed customers to the aggregator so that the latter could sell it on the market. In their representation, the supplier had to continue to supply the electricity intended for its load-shed customers. However, the logic and ingredients of this abstraction were not immediately understandable and were easily misused by the promoters of diffuse load shifting, leading to lasting confusion among the politicians involved in the successive decisions.

As soon as deliberation implies political legitimacy and takes place within a political body (and the associated media space), the question arises of how to arrange the confrontation of arguments, the clarification of hypotheses and perimeters, and the validation of models. The trajectory of the regulation of diffuse load shifting shows that political deliberation bodies are no better equipped to manage this complexity than technical bodies are configured to grasp the political dimensions of decisions. This argues for the invention of new deliberation rules that would allow these two dimensions to be brought in line.

Délibération de la CRE du 9 juillet

portant communication sur l'intégration des effacements diffus au sein du mécanisme d'ajustement (Decision of the ERC of 9 July 2009 concerning the integration of load shifting into the balancing mechanism).

Europe Ecologie les Verts.(2009, 07 20)

Decision N° 331858

Amendment (no. 16) presented by F. Brottes, during the debate on the energy transition law (on 10 October 2014)

Frédéric Blanc, legal expert at UFC-Que Choisir, quoted by Jade Lindgaard,: Prix de l'électricité : petits arrangements entre ennemis (Electricity prices: small arrangements between enemies),Médiapart, 11 February 2015

Acknowledgements

This work benefited from the discussions that took place in the framework of the COLLENER project, financed by the Agence Nationale de la Recherche (ANR, programme sociétés innovantes, convention 2011-SOIN-003-01). Boucher, P., 2012. The role of controversy, regulation and engineering in UK biofuel development. Energy Policy 42, 148-154. Doganova, L., Laurent, B., 2016. Keeping things different: coexistence within European markets for cleantech and biofuels. Journal of Cultural Economy 9, 141-156. Ehrenstein, V., Muniesa, F., 2013. The conditional sink: Counterfactual display in the valuation of a carbon offsetting reforestation project. Valuation Studies 1, 161-188. Laurent, B., 2015. The politics of European agencements: constructing a market of sustainable biofuels. Environmental Politics 24, 138-155. Lohmann, L., 2009. Toward a different debate in environmental accounting: The cases of carbon and cost-benefit. Accounting, organizations and society 34, 499-534. MacKenzie, D., 2008. Making Things the Same: Gases, Emission Rights and the Politics of Carbon Markets. Accounting, Organizations and Society 34, 440-455. Pallesen, T., Jenle, R.P., 2018. Organizing consumers for a decarbonized electricity system: calculative agencies and user scripts in a Danish demonstration project. Energy Research & Social Science 38, 102-109.


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MÉMOTVIT' : L'apprentissage d'un champ lexical métier par les cartes : retours d'expériences

MEMOTVIT', un jeu de cartes comportant des définitions, permettant à des apprenants d'acquérir des connaissances sur des champs lexicaux inhérents à une discipline, et ce par le biais d'une activité ludique, en équipe. C'est un jeu qui sollicite l'intelligence individuelle et collective ainsi que les sens. L'objectif est de fournir à l'apprenant la capacité à connaître un champ lexical par contextualisation en équipe, puis une décontextualisassions individuelle et enfin une recontextualisation en équipe. L'apprenant peut évaluer son niveau de connaissance en s'autoévaluant grâce à une évaluation formative seul ou en groupe, un questionnaire en ligne. L'équipe fondatrice

INTRODUCTION

La pédagogie par le jeu est une pratique favorable à l'apprentissage des adultes, enfants et étudiants. Cette pratique pédagogique stimule la créativité et la spontanéité de l'apprenant afin d'encourager son développement holistique [START_REF] Carnovalini | A rhythm-aware serious game for social interaction[END_REF]. Le recours au « serious games » ou jeux sérieux sont des outils pédagogiques des plus pertinents tout en étant en parfaite cohérence avec les pédagogies actives actuelles [START_REF] Kasbi | Les serious games : une révolution[END_REF] [START_REF] Clark | Serious Games[END_REF]. La conception d'un jeu sérieu, sa fabrication, sa mise en place et son inclusion dans une séquence pédagogique est un défi à relever [START_REF] Boudier | Serious game : Révolution pédagogique[END_REF]. Dans ce contexte, certains auteurs mettent à disposition des fondements ainsi que des exemples pratiques et des comparaisons avec les jeux de société ou jeux vidéo [START_REF] Alvarez | Du jeu vidéo au serious game : approches culturelle, pragmatique et formelle[END_REF] [6] [START_REF] Thalmann | An Overview of Serious Games[END_REF].

L'utilisation de support aux jeux tels que des plateaux ou des systèmes physiques permet aux joueurs (i.e. apprenants) une immersion, un contexte et environnement d'apprentissage inclusif ; autrement-dit, l'apprenant est acteur de sa formation. Des sociétés telles que CIPE (Centre International de la Pédagogie d'Entreprise) [START_REF] Cipe | Centre International de la Pédagogie d'Entreprise (CIPE)[END_REF] fournissent depuis les années 80 des moyens d'apprentissage par le jeu via des plateaux, cartes, jetons et diverses pièces tels que RÉACTIK, le jeu des Gentils-flux, ou le jeu KANBAN. Les jeux du CIPE sont utilisés en apprentissage thématique de la stratégie, la qualité, l'organisation du travail, la planification, la sécurité au travail ou la gestion de projet pour les entreprises. D'un point de vue académique ces jeux peuvent être également être utilisés tout comme des jeux créés par des enseignants chercheurs tels que Delta Design [START_REF] Bucciarelli | Delta Design: Seeing/Seeing as[END_REF].

Les établissements d'enseignement supérieur sont également des lieux où la création de jeux sérieux s'est développée. Par exemple, GopenDoRe créé par l'équipe DoRANum [START_REF] Gadrat | Jeu GopenDoRe : le jeu coopératif pour acquérir des bonnes pratiques de gestion et de partage des données de la recherche[END_REF], est un jeu de cartes coopératif pour l'acquisition de bonnes pratiques en gestion de partage de données. Sur la même thématique, le jeu FAIR-Play développé par le CIRAD de Montpellier est basé sur des cartes et un plateau [START_REF] Boussou | Libérez la science, un jeu FAIR-play[END_REF]. Le SCD de l'université de Guyane a mis au point un jeu de plateau Jeu Fastoche permettant l'appréhension du fonctionnement de l'archive ouverte HAL [START_REF] Latour | Jeu Fastoche HAL[END_REF]. L'ENSAM a développé plusieurs jeux pédagogiques tels que gAMustry 4.0 qui est jeu de plateau pour l'acculturation aux technologies 4.0. Ce jeu a été développé par L. Roucoules et l'équipe du campus de Aixen-Provence. G. Grampeix a développé dans le cadre de projets étudiants en 2 ème année le jeu SimCitiesDurable. Ce jeu de plateau a pour objectif de rendre une ville durable d'un point de vue environnemental. Par ailleurs, les auteurs ont travaillé conjointement au développement du jeu de cartes Mémotvit' et son inclusion dans la maquette pédagogique de formation d'ingénieur Arts et Métiers sur le campus de Cluny.

Ainsi, l'article traite de la genèse de MEMOTVIT', de sa conception, de son déploiement dans une séquence pédagogique, de son évaluation ainsi que de sa valorisation et dissémination.

ORIGINE DE LA DEMARCHE ET DEFINITION DU JEU

Le dispositif d'apprentissage MEMOTVIT' a été initié par une expérience vécue lors de la visite du service SAPIENS de l'USPC [START_REF] Cri | SAPIENS -Alliance Sorbonne Paris Cité[END_REF] par les auteurs en 2017. L'objectif de l'expérience était la découverte d'intégrer le jeu dans certaines activités d'apprentissage. Notamment, le recours à des cartes au service de l'acquisition d'un champ lexical thématique inhérent aux disciplines ou métiers a permis l'émergence de MEMOTVIT' au sein du campus Arts et Métiers de Cluny.

Les auteurs, pour certains, ayant une expérience dans la discipline de métrologie (i.e. science de la mesure) ont vu une belle opportunité de proposer un jeu de cartes (un mot + une définition + un lien vers le Vocabulaire International de Métrologie (VIM) en ligne [START_REF] Jcgm | Vocabulaire International de Métrologie légale (VIM) -Bureau International[END_REF]) pour faire acquérir aux élèves ingénieurs des

METHODOLOGIE MISE EN OEUVRE ET DIMENSIONS NUMERIQUES, SPATIALES ET ORGANISATION-

NELLES

Le jeu comprend une règle du jeu et 76 cartes : 70 définitions et 6 cartes blanches permettant d'apposer un mot et définition au gré de ses envies ou pour faire apprendre un mot de vocabulaire ne figurant pas dans la liste initialement établie. Ces cartes sont contenues dans un étui en bois réalisé en interne par les auteurs [START_REF] Arts | Fablab Clunisois[END_REF] tout comme le graphisme [START_REF] Trujillo | EMTrujillo My Portfolio -Memotvit[END_REF] comme le montre la Figure 1. -Examen de milieu de séquence pédagogique ; -2 x 4hs de travaux pratiques où l'étudiant est mis en situation devant des problématiques techniques et industrielles de métrologie pour lesquelles ils doivent proposer des solutions et les mettre en place ; -Examen de fin de séquence pédagogique.

Durant la dernière heure de CM, le jeu est proposé aux élèves. L'élève découvre une activité hors du cadre dont il est familier (i.e. pédagogie déductive ou inductive).

L'activité dure 40 min pour un groupe de 24 étudiants. Une première partie de contextualisation en groupe où l'enseignant choisi certaines cartes en fonction des connaissances que doivent acquérir les étudiants. Il lit ensuite les cartes : le mot présenté ainsi que sa définition. Il explique les concepts associés en s'appuyant sur des rappels du cours. Ensuite deux équipes de 12 sont formées pour réaliser l'activité. C'est la partie de décontextualisation. L'étudiant est libre de ses choix. Les idées et la façon de faire deviner le mot durant les trois manches (i.e. parole, puis un mot et enfin le mime) par un étudiant au reste du groupe sont notés au tableau par l'enseignant ainsi que les points acquis par les deux équipes. Ensuite à la fin de l'activité, la recontextualisation faite par l'enseignant avec la participation des étudiants permet de revenir sur les idées et méthodes déployées par ces derniers pour faire deviner un mot de vocabulaire. Finalement une synthèse sur les définitions trouvées est faite par l'enseignant. Les apprenants sont invités à se positionner via un questionnaire formatif d'appariement sur la plateforme d'e-learning. Ce questionnaire peut être réitéré sans Carry-le-Rouet, 4-6 avril 2023 limite ou complété à n'importe quel moment dans la séquence pédagogique.

Les séances de travaux pratiques (TPs) suivantes feront appel aux termes du champ lexical de la métrologie qui ont été vu durant l'activité MEMOTVIT'. Ces TPs pourront permettre à l'étudiant de s'évaluer ou d'être évalué de manière formative vis-à-vis de ses acquis d'apprentissage sur ce dit champ lexical. En effet, au sein des sujets de TPs, des documents ressources, des mises en situations de l'étudiants ainsi que dans le discours de l'enseignant, ce champ lexical sera omniprésent.

IMPLICATION DE L'EQUIPE PEDAGOGIQUE, DES ETUDIANTS, ET DE LA GOUVERNANCE

La direction du campus et la direction à la formation ont été informées en priorité de la volonté d'inclusion du jeu en pédagogie. L'initiative d'insertion de la pédagogie par le jeu a suscité l'intérêt par rapport à la politique de l'ENSAM et notamment du campus de Cluny sur le plan d'innovation pédagogique.

Aussi, parmi les auteurs, il y a du personnel de la bibliothèque du campus. En effet, ses compétences en pédagogie, en documentation et le lien particulier qu'il tisse avec les étudiants par ses fonctions a été forces de propositions et essentiel à l'aboutissement du projet MEMOTVIT'. Conjointement aux réflexions, un travail de graphisme et reprographie a permis un conditionnement et une esthétique assurant une certaine crédibilité envers des étudiants ingénieurs. Un ingénieur pédagogique de l'ICIFtech [START_REF]Institut de Conseil et d'Innovation en Formations Technologiques[END_REF] et enseignant la métrologie complète les auteurs.

À la suite du montage du jeu MEMOTVIT', avant son insertion dans la maquette pédagogique présentée à la section 2, le jeu a été « bêta-testé » en présence des auteurs, d'enseignants, du personnel de la bibliothèque, et d'étudiants en 1 ère et 2 ème année (délégués aux travail (1 par groupe d'ED) et délégué à la pédagogie (un par promotion)). L'équipe a pu en extraire des éléments à modifier. Elle a sondé l'impressions des participants et fait évoluer le jeu MEMOTVIT' avant sa mise en place comme le montre la Figure 2. L'initiative d'insertion de la pédagogie par le jeu a suscité l'intérêt par rapport à la volonté du campus de Cluny et une politique nationale de l'ENSAM sur la création de plateformes d'innovations pédagogiques comme le projet ACCENS piloté par l'ICIFTech [START_REF]Institut de Conseil et d'Innovation en Formations Technologiques[END_REF] et de moyens pédagogiques novateurs notamment par projet (p.ex. projet APLA [START_REF] Kazakevičius | Le Futur De L'Enseignement Et De L'Apprentissage Aux Arts Et Métiers Paristech aménagement et programmation de laboratoires d'apprentissage[END_REF]). En effet, ces plateformes mettent à disposition des espaces ayant des configurations modulaires et d'équipements différents pour répondre aux besoins spécifiques de chaque campus pour l'apprentissage : par la collaboration, en groupe ou individuel, par l'expérience, le jeu, la communication pour l'expression. Ainsi l'apprenant y développe sa créativité, peut collecter, travailler, pratiquer et créer.

PUBLIC CONCERNES, BENEFICIAIRES

Bénéficiaires de 1er plan

Les élèves ingénieurs de l'ENSAM Cluny utilisent ce jeu lors d'activités pédagogiques d'apprentissage (cours ou TPs) encadrées par l'enseignant depuis 2018. L'objectif est d'acquérir des connaissances relatives aux champs lexicaux d'unités d'enseignement ou de métiers (p. ex. dans sa 1ère version : « la métrologie »).

Bénéficiaires de 2ème plan

Les étudiants de l'ENSAM des 8 campus implantés sur le territoire français car le jeu sera disséminé dans les 7 autres bibliothèques des campus et pourra servir plus largement à d'autres enseignants.

Bénéficiaires de 3ème plan

D'autres formations d'enseignement du secondaire ou du supérieur en France ou à l'étranger voulant faire découvrir du vocabulaire propre à une discipline. Les industriels sont intéressés par l'utilisation de ce jeu dans le cadre de leur formation de personnel en interne.

CONTEXTES D'APPRENTISSAGE ET DE FORMATION

Intégration dans la maquette pédagogique

Le jeu MÉMOTVIT' est inscrit en enseignement de métrologie ; module faisant partie intégrante de l'unité d'enseignement d'ingénierie (UEI) « Réaliser -Système » de la formation d'ingénieur de l'ENSAM Cluny. L'activité MEMOTVIT' place l'étudiants seul ou en groupe en fonction de l'étape du jeu, au coeur de sa formation. Le jeu lui permet ainsi d'être acteur et d'être pleinement impliqué dans l'acquisition de connaissances d'un champ lexical spécifique à une discipline. Cette formation est évaluée d'un point de vue formatif à la fin de la séquence pédagogique. L'étudiant, avec accès au VIM [START_REF] Jcgm | Vocabulaire International de Métrologie légale (VIM) -Bureau International[END_REF], et par un questionnaire formatif, peut progresser dans des conditions saines et détendue. Le test donne lieu à une évaluation chiffrée mais qui ne sera pas comptabilisée dans le dossier de l'étudiant. La note joue uniquement le rôle de curseur pour permettre à l'étudiant de situer son niveau d'apprentissage.

Evaluation ou auto-évaluation formative

L'évaluation formative permet à l'apprenant de prendre conscience de ses difficultés, de ses erreurs, de ses hésitations, de ses dépassements, de ses progrès. L'évaluation formative donne de l'autonomie en stimulant la prise de conscience. Elle redonne la confiance et l'intérêt dans l'apprentissage en éliminant le stress de la mauvaise note, et permet à l'élève de ne pas finir l'année avec une très mauvaise opinion par la matière qu'on lui enseigne et de lui-même. Cette approche contribue à installer un climat de confiance et des interactions plus riches, plus positives, et à terme, plus efficaces entre étudiants et enseignants.

L'étudiant reçoit un retour individualisé de son questionnaire (i.e. feed-back) favorisant son apprentissage et le rendant acteur. Les responsabilités classiques de l'enseignant (évaluation, régulation) sont maintenant partagées avec l'apprenant (autoévaluation, autogestion des erreurs, autorégulation), ce qui augmente considérablement l'efficacité de la pédagogie.

Le questionnaire formatif d'appariement sur Moodle proposé en séance est partiellement illustrée à la Figure 4. Il peut être rempli n'importe quand dans la séquence et sans contraintes de temps. La Figure 5Figure 5, quant à elle, présente les résultats de 87 participants dont seulement 49 ont choisi de terminer le test. Le questionnaire permet de récupérer les informations suivantes : Prénom et nom de l'apprenant inscrit au cours et ayant débuté le questionnaire, son adresse électronique, l'état d'avancement du questionnaire, la date à laquelle la réponse au questionnaire a débuté, la date de fin et ainsi le temps passé pour le compléter, le taux de réussite de chaque onglet thématique (Figure 4.), une note par étudiant, une moyenne et dispersion de l'activité, une moyenne et dispersion pour chaque onglet thématique .Il est également possible de récupérer la tendance et la progression de chaque étudiant dans la complétude du questionnaire. Chaque étudiant connaît son taux de réussite et son état de progression en temps réel. En revanche ni le résultat sur une promotion ni le positionnement de l'étudiant par rapport au reste de la promotion sont dévoilés. L'étudiant peut également réitérer le questionnaire autant de fois qu'il le souhaite durant la phase de révision de l'UE.

Dans un avenir proche, le questionnaire sera disponible sur la plateforme Wooclap (application d'interaction en classe) et ainsi il pourra être mené directement en salle avec une participation en temps réel des étudiants via l'utilisation de leur téléphone portable.

FINALITE DE LA DEMARCHE

La finalité de la démarche de pédagogie par le jeu via l'outil MEMOTVIT' entraîne l'étudiant à utiliser des termes usuels associés à la thématique, discipline ou métiers associés au jeu (ici dans cette version « la métrologie »). Pour cela, il doit :

-Maîtriser l'orthographe des mots, -Maîtriser le sens de la définition, -Être capable de restituer et utiliser le mot dans un contexte particulier.

Types de capacités et acquis d'apprentissages concernés/visés

Les capacités et acquis d'apprentissages concernés sont les suivants :

-Communiquer dans une logique professionnelle, -S'inscrire dans une dynamique professionnelle, -S'entrainer aux situations professionnelles avec un vocable adapté, -Mieux se connaître et se projeter selon les exigences et contraintes professionnelles, -Identifier / reconnaître les différences lexicales afin d'éviter les malentendus, et de commettre des impairs dans une discipline ou un métier, -Adapter son comportement et son langage à un interlocuteur francophone ou anglophone et cela en fonction de la discipline dans laquelle il y a des échanges, -Évoluer et travailler en équipe. En effet, l'étudiant doit se mobiliser rapidement et en équipe afin d'apprendre.

Variantes du jeu

Plusieurs variantes du jeu sont possibles et disponibles. La première est l'insertion de 6 cartes vierges. Pour adapter le jeu à ses exigences, avant le début de la partie, l'animateur ou les joueurs peuvent insérer à leur guise des expressions (et éventuellement les définitions associées) sur des cartes blanches plastifiées fournies.

La seconde permet à l'enseignant ou l'animateur de décider en début de partie que les joueurs peuvent écarter une carte lors de leur tour, le joueur est alors pénalisé. La pénalité consiste à ce que son équipe lui fasse deviner le mot suivant.

Une dernière variante est la pose de carte sur un bandeau (Figure 6) permettant à la carte d'être visible des participants mais pas du porteur. Ainsi ce dernier doit deviner sa carte en fonction des dires, faits et gestes d'un autre participant.

Rôle du formateur

Le formateur, animateur et/ou enseignant a un rôle majeur dans l'activité. Tout d'abord il a un rôle d'arbitrage des deux équipes et du bon respect des règles sous peine de point ou temps de pénalité.

Son rôle principal, de par sa maîtrise du vocable présent dans le jeu, doit pouvoir aiguiller les apprenants s'il y a vraiment des difficultés. Une explication précise des mots et définition est donnée avant le jeu en s'appuyant sur des cas pratiques, industriels ou de laboratoires afin de contextualiser le mot de vocabulaire.

Il a pour rôle de comptabiliser les points et les méthodes employées par les étudiants (mots, mimes et gestuelles employés). À la fin de l'activité, l'enseignant recontextualise avec la participation des étudiants, ce qui permet de revenir sur les idées et méthodes déployées pour faire deviner un mot, avant de réaliser une synthèse sur les définitions rencontrées.

Evaluation du projet MEMOTVIT' : mesure des effets et possibles évolutions

Le jeu est suivi d'un questionnaire d'évaluation de l'activité par les étudiants ayant participé. Ce questionnaire a pour objectif d'avoir un retour rapide des étudiants, et des commentaires ayant permis des améliorations du jeu à ses débuts et permet désormais d'ajuster la séquence de jeu en pédagogie.

L'objectif de ce questionnaire est d'obtenir des informations en peu de temps et pour un grand nombre d'étudiants. Ainsi il reste sous un format manuscrit pour rester efficient. À l'avenir, ce questionnaire sera informatisé pour faciliter son traitement ainsi que la minimisation de papier consommé (3 sondages par feuille, format DL selon l'ISO 269 soit 9,9 x 21 cm). Cette informatisation risque de voir le nombre de participation à cette évaluation baisser car cela laisserait l'étudiant libre de le remplir ou non.

Par ailleurs de nombreux échanges avec des étudiants et des enseignants ont permis de mettre au point la pratique de cette activité et une meilleure pratique plus efficace et rapide tant sur sa mise en place que sur la mémorisation des mots et leur définition.

En

Perspectives de transférabilité de la démarche

Le jeu est mis en place dans la maquette pédagogique et est fonctionnel depuis l'année universitaire 2018. Une démarche de dissémination est en cours auprès des bibliothèques ENSAM.

De plus, un rapprochement est en cours avec l'IUT de Clermont-Ferrand, l'IUT de Toulon ainsi que INP Grenoble.

En ce qui concerne une diffusion plus large (i.e. ESR, industrie, etc), le jeu a suscité de l'intérêt auprès de la société Michelin pour de la formation en interne. Un rapprochement avec la société Ikigai -Games [START_REF] Games | IKIGAI Games" Association Games for Citizens[END_REF] pourrait également permettre une diffusion numérique de ce jeu. A des fins de protection, conjointement avec le service juridique de l'ENSAM, et un dépôt de marque et de logo a été établi en juillet 2022 auprès de l'INPI [START_REF] Ensam | Memotvit[END_REF].

L'ICIFTech, a également décliné le jeu avec une version d'acquisition de champ lexical de « La pédagogie » plutôt que « La Métrologie » pour former les nouveaux enseignants de l'ENSAM durant leur séminaires d'accueil.

Une candidature en 2019 au prix PEPS [START_REF] De L'esr | Passion Enseignement et Pédagogie dans le Supérieur, PRix 2019[END_REF] a été soumise.

CONCLUSION

Ce papier dresse un bilan, et retours d'expériences d'inclusion du jeu en pédagogie. Une synthèse sur la génèse du jeu MEMOTVIT', sa conception est menée. La description de l'inclusion du jeu dans une séquence pédagogique inductive est illustrée et l'évaluation formative des étudiants permettant une amélioration continue de l'activité depuis 2018 en est faite. Une perspective au projet MEMOTVIT' est sa dissémination auprès d'établissement d'enseignement, ainsi que dans des entreprises industrielles et sa conversion numérique.

REMERCIEMENTS

Les auteurs tiennent à remercier les différents services supports de l'ENSAM qui ont permis l'émergence de MEMOTVIT', sa mise en place ainsi que de la valorisation de l'outil pédagogique. Un remerciement spécial à l'ICIFTech pour son support. Les derniers remerciements vont aux étudiants à compter de la promotion entrante en 2017 qui ont apporté leur retours d'expériences lors du bêta-test de ce jeu, et qui l'ont utilisé dans la séquence pédagogique de métrologie ou hors contexte.

Figure 1 :

 1 Figure 1 : Illustration du jeu complet MEMOTVIT' (76 cartes et règle du jeu à gauche et exemple d'une carte à droite).

Figure 2 :

 2 Figure 2 : Bêta-test du jeu MEMOTVIT'

Figure 3 : 6 . 2 .

 362 Figure 3 : Description des unités d'enseignement composant la 1ère année de formation de l'ENSAM -Mise en exergue de l'UEI où est intégrée MEMOTVIT'.

Figure 4 :

 4 Figure 4 : Illustration du questionnaire en ligne sur SAVOIR : questionnaire d'évaluation formative.

Figure 5 :

 5 Figure 5 : Résultat d'évaluation formative sur 87 participants dont seulement 49 l'ont terminée : En orange, information concernant chaque apprenant ; en noir, moyenne globale par questions ; enfin histogramme de répartition des participants.

Figure 6 :

 6 Figure 6 : Illustration d'une variante proposée du jeu MEMOTVIT'.

Figure 7

 7 est présenté les résultats du sondage auprès d'une demi-promotion sur un semestre. Il est possible d'observer par la tendance que l'activité est très bien perçue par les étudiants. Cependant, les étudiants restent peu convaincus que l'activité peut être faite hors des séances pédagogiques malgré qu'une version est disponible en bibliothèque (sur place ou en emprunt) et que certains étudiants l'utilisent hors séance. De plus, cela ne permet pas forcément de désacraliser la discipline qui reste difficile à comprendre et à maîtriser. En effet, elle nécessite une exigence et une exactitude sur le fond scientifique, verbal et de mise en oeuvre ; elle qui reste parfois contraignante pour les apprenants.

Figure 7 :

 7 Figure 7 : Résultats du questionnaire d'évaluation de l'activité MEMOTVIT' par les étudiants de 1ère année PGE durant le 1er semestre de l'année universitaire 2018-2019.

  travaux dirigés avec une mise en situation des étudiants sur des problématiques de mesure. -S'en suit, 2 x 2 hs de CM par accompagnement où l'étudiant est au centre (i.e. est acteur) de sa formation. En effet, il a accès à un certain nombre de ressources (e.g. support de cours, ouvrages articles, résultats de travaux, vidéos, etc.) sur la plateforme d'e-learning Moodle de l'ENSAM Cluny. Il peut interagir avec l'enseignant par des questions ou lors des interventions de l'enseignant. Les acquis d'apprentissage visés sont la compréhension et la mémorisation des notions de métrologie, son histoire, les outils mathématiques et la mise en place d'une activité de mesure à partir de la définition du mesurande jusqu'au calcul d'incertitude de mesure.

	La règle du jeu autorise deux contextes : un premier en
	séquence pédagogique encadrée par un enseignant, et un
	second d'auto-formation de l'apprenant. En séance
	d'enseignement à l'ENSAM, l'activité nécessite une salle
	informatique avec accès au VIM, et à la plateforme d'e-
	learning Moodle nommé SAVOIR à l'ENSAM, un jeu de
	cartes (76 cartes, une règle), un chronomètre, un tableau,
	un questionnaire d'évaluation distribué à chaque
	étudiant.
	L'activité s'inscrit dans une unité d'enseignement de
	métrologie comprenant une approche inductive :
	-2hs de

ème Colloque national S.mart