This dissertation explores the functional purpose of imagination as it is enacted in the context of shaping large transitions in sociotechnical systems. Large sociotechnical systems undergoing profound transitions embody instantiations where societies experience profound changes in the ‘rules of the game’ that underpin the conduct of daily life. The forms of imagination that guide these transformations, known in the political theory literature as ‘imaginaries,’ play a profound yet undertheorized role in transition of sociotechnical systems from one configuration to another. Expanding on this relationship, the study draws on three case studies of energy systems change in the United States during 20th and 21st century. Each case study explores unique element of how actors at a variety of levels – transnational governance, regional electrification, and in-home energy marketing – define and the possibilities for ideal human and technological action and interaction through a transition. These actors defining the parameters of a new form of systems operation and configuration are as equally focused on defining how these new configurations shape fundamental ideas that underpin American democratic sensibility. Moreover, in the process of articulating a new configuration of energy and society – be that in terms of managing global resource flows or the automation of energy use in a residential home – questions of what makes an ideal member of a society are interlinked with new contractual relationships between energy producers and energy users. Transitions research could and should pay greater attention to the normative commitments emergent systems actors – as it is in these commitments we can chart pathways to redefine the parameters that underpin emergent transitions.