'The public' are potentially implicated in processes of sociotechnical change as political actors who welcome or resist technology development in general, or in particular places and settings. We argue in this paper that the potential influence of public subjectivities on sociotechnical change is realised not only through moments of active participation and protest, but also through 'the public' being imagined, given agency, and invoked for various purposes by actors in technical industrial and policy networks. As a case study we explore the significance of an imagined and anticipated public subjectivity for the development of renewable energy technologies in the UK. We use interviews with a diversity of industry and policy actors to explore how imaginaries of the public are constructed from first-hand and mediated experience and knowledge, and the influence these imagined public subjectivitics may have on development trajectories and on actor strategics and activities. We show how the shared expectation of an ever present latent but conditional public hostility to renewable energy project development is seen as shaping the material forms of the technologies, their evolving spatiality, and practices of public engagement involved in obtaining project consent. Implications for the actors we are interested in and for broader questions of democratic practice are considered.