Proximity and low-carbon initiatives have become the new metrics of energy transition programmes that have been carried out over the last decade. These new goals have intensely transformed both the functioning (and management) of urban technical services and the energy strategies designed by local authorities, as they were supposed to lower the dependency of territories on fossil energies and their volatile markets. The renaissance of district heating systems and their recent transformations illustrates these ongoing changes where proximity rimes with priority. In this article, I study the reconfigurations of a district heating network in the German mid-sized city of Magdeburg and analyse how a new infrastructure regime develops and is structured by proximity and energy efficiency. The article shows both the successes and pitfalls of these emerging strategies, as they sometimes lead to the creation of new forms of vulnerability that affect urban technical services.