Politicised nexus thinking in practice: Integrating urban wastewater utilities into regional energy markets

Infrastructures are key interfaces of urban resource use, connecting production to consumption, cities to their hinterland and energy to water and land use. They have, however, received scant attention in debates on nexus thinking in general, and the urban nexus in particular. Drawing on an emergent critical literature on the nexus in urban studies and science and technology studies, this article examines practices of (attempted) inter-sectoral infrastructure integration at the interface of urban wastewater treatment and regional energy provision in Germany. It analyses the nexus approaches and experiences of eight German cities / city-regions as so-called ‘flexibility providers’ in regional energy markets for electricity, gas and heating. It demonstrates how the practices of wastewater utilities operating in energy markets involve far more than technical adaptation, requiring in addition a major reordering of existing material, spatial and institutional configurations to both wastewater and energy systems. This is proving a deeply political process with important implications for our understanding of socio-technical transitions at the water-energy nexus.