Through the analysis of energy supply choices, this article explores the way in which energy priorities and their climate-related features are incorporated into urban public policy. These choices must take account of different factors, as is the case with district heating, which is justified as a vehicle of renewable energy while subject to pressure in eco-districts because its techno-economic balances are destabilised by falls in demand. Our study focuses particularly on the city of Metz (France), which has chosen district heating as the primary source for provision for the municipal area and for its firsr eco-district. We analyse the tensions within these choices, with particular attention to the way in which they are negotiated inside municipal departments and with the local energy operator. This enables us to explore the tensions in defining the scale that governs decisions and the linkages between energy-related and urban priorities. (C) 2014 Elsevier Ltd. All rights reserved.