Olivier Vidal

La recherche sur la transition énergétique pose plusieurs défis de taille : c’est une recherche orientée problème (celui de la décarbonation du mix énergétique), qui doit être résolument éthique et intégrer dès sa formulation des principes de justice sociale et environnementale…, et ce alors même que la notion de transition est problématique en cela qu’elle donne l’impression que le processus qui mènera aux changements attendus – si changements il y a – sera linéaire et fondé sur la substitution d’une source d’énergie par une autre. Partant de ce constat, ce texte dresse des pistes de recherche sur des thématiques saillantes, notamment sur les acteurs et échelles des transitions, les techniques et leurs externalités, les modèles économiques et sociaux qui permettent de guider l’action, les modèles de consommation et de production, et il s’interroge sur les rapports entre consommation et production. Il défend in fine l’idée que la recherche, forcément interdisciplinaire et réflexive, a un rôle fort à jouer pour fonder l’action en matière de transition sur des constats scientifiquement fondés.

Humanity is using mineral resources at an unprecedented rate, and demand will continue to grow over the coming decades, fuelled by the energy and digital transitions and the economic development of highly populated countries. But the nature and quantities of mineral resources needed are highly dependent on the types of use envisaged, which vary according to the organisation and level of development of societies. The demand for raw materials must therefore be estimated using a dynamic and regionalised approach, taking into account the different development scenarios, particularly as regards the deployment of renewable or decarbonised energy resources. This article summarises the main analyses of previously published articles by Olivier Vidal et al. [1-4].

Consumption-based carbon assessments are essential for evaluating climate change responsibility. However, the results vary greatly depending on the boundary chosen, making them hard to understand for non-expert readers and hindering their uptake by policy makers. Sankey diagrams are a type of flow diagram where the thickness of a flow is proportional to its value. They allow to shed light on the various ways to calculate carbon footprints and on the implications of choosing one method over another. Although several multi-regional input-output databases allow for the calculation of footprints, none of them has been systematically represented as Sankey diagrams. To fill this gap, we build an open access web application to represent carbon footprints for 49 world regions between 1995 and 2019 based on EXIOBASE 3 data. We include production-based, consumption-based and consumption-based with capital endogenized accounts. We then provide examples of the insights gained with such diagrams.

L’humanité utilise les ressources minérales à un niveau sans précédent et la demande va continuer de croitre au cours des prochaines décennies, alimentée par les transitions énergétique et numérique et le développement économique des pays très peuplés. Mais la nature et les quantités de ressources minérales nécessaires sont fortement dépendantes des types d’utilisation envisagés, lesquels varient selon l’organisation et le niveau de développement des sociétés.La demande en matières premières doit donc être estimée selon une approche dynamique et régionalisée, prenant en compte les différents scénarios de développement, notamment pour ce qui concerne le déploiement de ressources énergétiques renouvelables ou décarbonées.Le présent article reprend en les résumant les principales analyses d’articles précédemment publiés d’Olivier Vidal et al. [1-4].

To maintain perpetual economic growth, most energy transition scenarios bet on a break in the historical relationship between energy use and gross domestic product (GDP). Practical limits to energy efficiency are overlooked by such scenarios, in particular the fact that high-income individuals tend to buy goods and services that are more energy intensive. Detailed assessments of the energy embodied in regional final consumption are needed to better understand the relationship between energy and GDP. Here, we calculate the energy necessary to produce households and governments' final consumption in 49 world regions in 2017. We correct prices at the sector level and account for the energy embodied in the whole value chain, including capital goods. We find that high-income regions use more energy per unit of final consumption than low-income ones. This result contradicts the common belief that a higher GDP is correlated with a better efficiency and questions the feasibility of mainstream energy transition scenarios based on universal GDP growth.

Humanity is using mineral resources at an unprecedented level and demand will continue to grow over the next few decades before stabilizing by the end of the century, due to the economic development of populated countries and the energy and digital transitions. The demand for raw materials must be estimated with a bottom-up and regionalised approach and the supply capacity with approaches coupling long-term prices with energy and production costs controlled by the quality of the resource and the rate of technological improvement that depends on thermodynamic limits. Such modelling provides arguments in favour of two classically opposed visions of the future of mineral resources: an unaffordable increase in costs and prices following the depletion of high quality deposits or, on the contrary, a favourable compensation by technological improvements. Both views are true, but not at the same time. After a period of energy and production cost gains, we now appear to be entering a pivotal period of long-term production cost increases as we approach the minimum practical energy and thermodynamic limits for many metals.

Humanity is using mineral resources at an unprecedented level and demand will 1 continue to grow over the next few decades before stabilizing by the end of the century, due to 2 the economic development of populated countries and the energy and digital transitions. The 3 demand for raw materials must be estimated with a bottom-up and regionalized approach, and 4 the supply capacity with approaches coupling long-term prices with energy and production costs 5 controlled by the quality of the resource and the rate of technological improvement that depends on 6 thermodynamic limits. Such modelling provides arguments in favour of two classically opposed 7 visions of the future of mineral resources: an unaffordable increase in costs and prices following the 8 depletion of high quality deposits or, on the contrary, a favourable compensation by technological 9 improvements. Both views are true, but not at the same time. After a period of energy and 10 production cost gains, we now appear to be entering a pivotal period of long-term production 11 cost increases as we approach the minimum practical energy and thermodynamic limits for many 12 metals.

The dynamics of copper production is modelled with a prey-predator approach linking the evolution of reserves to that of industrial wealth. Our model differs from earlier approaches in that it does not require a priori knowledge of the initial stock of resources. The model variables and a long-term reference price are estimated from historical data, taking into account the combined effects on price and reserves of technological improvements and changes in ore grade. The business-as-usual scenarios invariably lead to a peak of primary production by the middle of the century. The peak of production is not the result of the complete exhaustion of exploitable copper, but of the combination of 1) the deviation of reserves growth from the exponential historical trend and 2) the incapacity of technological improvements to offset the increase in production costs. In the leveled-off-demand scenario for which future demand is simulated based on assumed evolutions of world population and GDP per capita, no collapse of primary production is observed within the century for optimistic regeneration of reserves and a collection-recycling rate reaching 70% by 2100, at constant energy prices.

The evolution from 2000 to 2050 of the needs in concrete, steel, aluminium and copper to build the infrastructure of electricity generation is modelled for the scenarios of García-Olivares et al. (2012), Ecofys-WWF (2012) and the blue map scenario of the IEA (2010). A simple dynamic model is used to estimate the primary production, recycling and lost flows as well as the cumulative stocks of material to be produced, to go into the infrastructure and to be lost. The energy of material production is also estimated. When compared with the expected evolution of global material and energy demands, the modelling results suggest that i) the transition to low-carbon energies implies a substantial increase of raw materials and energy consumption, ii) the shorter lifetime of wind and solar facilities and the loss of recycling implies that the total amount of metal to be produced during the deployment of the infrastructure of energy is significantly higher than their amount stocked in the infrastructure, and iii) the needs in materials and energy will occur in a period of expected increase of primary metal consumption at the world scale and limited potential of recycling