Sustainable energy transformation should not be just a technical or organizational mode of governance. It should be embedded in its socio-political context and reflect challenges as perceived by relevant actors and as framed by the relevant institutions on different scales. The paper explores practices of inter-sectoral integration of new decentralized actors into transformed energy politics and infrastructures. The paper poses the question: “Why, how and for whom would actors (like grid operators) integrate municipal utilities (e.g. wastewater treatment plants) into transformed energy markets and infrastructures?” Analyzing fresh empirical fieldwork (interviews) the paper offers insights into the German “Energiewende”, showing how local actors are participating in restructured regional, national and European energy markets. The author is investigating how powerful incumbent actors of energy provision are defending their market shares within rescaled institutional settings. Framing our research in terms of familiar concepts of integrated resources management and politics of scale, aiming thereby to make a substantial contribution to political science research on the energy transformation.