Zélia Hampikian: From distribution to synergies? Local energy flows and transformations in the city’s networking processes

Within the discourse framed by a commitment to energy transition, there is a growing emphasis on promoting energy flows at sub-urban scales between various activities. Local, national and transnational stakeholders are, for example, proposing to recover so-called ‘waste heat’ produced by a wide range of activities (industry, data centres, wastewater treatment, etc.). At the same time, there is a push to share decentralised energy production across different sectors (residential, tertiary, commercial, etc.) at scales ranging from the block to the neighbourhood. In short, forms of connection between urban activities for the exchange of energy are being promoted, and examples of their implementation are multiplying.

This thesis proposes to view these connections as new forms of urban networks, which are replacing or overlapping with a model of a large, centralised network that is over a century old, based on technical and economic efficiency, territorial integration and increased consumption. It aims to understand how the emergence of these local flows is changing the co-construction of the city and energy networks.

To understand these transformations, this thesis draws on two strands of research. On the one hand, urban and socio-technical research on networks helps to understand the reconfigurations of these infrastructures. On the other hand, the field of industrial and territorial ecology analyses the dynamics that lead to the exchange of material flows between human activities. Combining these findings thus enables us to understand the subject under consideration in its social, technical and metabolic dimensions, that is to say, from a socio-material perspective.

The analysis is based primarily on three case studies, focusing on understanding their emergence, operation and development: the supply of Dunkirk’s district heating network via an industrial heat source, heat recovery from a data centre to supply a neighbourhood in Marne-la-Vallée, and the pooling of energy production in the La Confluence neighbourhood of Lyon. More broadly, the study examines concrete or proposed reconfigurations of the organisation of the urban energy supply chain.

The findings of the thesis fall into three categories. Firstly, these networks are no longer driven solely by the technical and economic efficiency of the networked structure for supplying the region. The interests of the various actors involved all relate to the objective of optimising the use of flows: there is thus a shift from a quest for technical and economic efficiency to one of metabolic efficiency. Secondly, the networks emerging from these exchanges are unstable, particularly due to uncertainties regarding the short- and long-term evolution of available flows. Consequently, they do not replicate the unifying effect afforded by the stability of large conventional networks. Finally, in the face of these instabilities, the stakeholders propose developments aimed at reducing dependencies on uncertain flows. These developments are characterised by relying on network growth that no longer pursues a goal of universalisation. On the contrary, a strict spatial selection of network expansion is applied, based on the actuality of flows as perceived by the stakeholders. Rather than generating new consumption through a supply-driven approach, the aim is thus to integrate new flows already present in the region.

In short, the thesis highlights a certain ‘metabolic shift’ in the process of connecting the city through energy. Whilst the expansion of infrastructure has long been at the heart of network development, the flows of energy produced and consumed that already exist within the area may now be the primary motivation for establishing connections.

Members of the jury

• Sabine Barles, Professor, University of Paris 1 Panthéon-Sorbonne (rapporteur)
• Nicolas Buclet, Professor, Université Grenoble Alpes (examiner)
• Olivier Coutard, Research Director, CNRS, UMR LATTS (examiner)
• Gilles Debizet, Senior Lecturer, Université Grenoble Alpes (examiner)
• Gabriel Dupuy, Professor, University of Paris 1 Panthéon-Sorbonne (rapporteur)
• Laurence Rocher, Senior Lecturer, Université Grenoble Alpes (examiner)
• Taoufik Souami, Professor, University of Paris-Est (supervisor)