Energy planning and the realization of a new energetic infrastructure has become an issue for many actors. The local setting has become polycentric. Against this background the authors have tried to answer the question of the possible consequences of a polycentric local decision-making arena for the realization of sustainable energy transition, especially the implementation of smart grids. Polycentrism is characterised by configurations of units that are multi-level, multi-purpose, multi-sectoral and multi-functional. The impact of these configurations can be assessed using four criteria: control, efficiency, political representation and local self-determination. The authors used these criteria to analyse two cases. Both cases show that the consequences of polycentrism are variable and differ on the four criteria. The analysis shows tensions in polycentric configurations between control and efficiency on the one hand and local self-determination and political representation on the other. This outcome was a reason for the authors to argue for a better institutional design for the local polycentric arena with the help of the seven ‘rules-in-use’ of Elinor Ostrom. Her design is universal but requires specific local application. In this way more justice can be done to the local circumstances in order to be able to achieve effective results.