Abstract:We outline a future where society re-energises itself, in the sense both of recapturing creative dynamism, and of applying creativity to meeting physical energy needs. Both require us to embrace self-organising properties, whether in nature or society. We critically appraise backcasting as a methodology for visioning, arguing that backcasting's potential for radical, outside-the-box thinking is restricted unless it contemplates a break with class society, connects with existing grassroots struggles (notably over land) and dialogues with utopian socialist tradition. We develop a case study of food, starting from the physical parameters of combatting the entropy expressed in the loss of soil structure, and apply this to urban food-growing. Drawing upon 'real utopias' of existing practice, the paper proposes a threefold categorisation: subsistence plots, an urban forest, and an ultra-high productivity sector. We emphasise the emergent properties of such a complex system characterised by the 'free energy' of societal self-organisation. Barling et al, 2008), backcasting, in contrast, begins from a desired outcome and then assesses the steps by which it may be reached. The methodology has particular relevance to the theme of this special issue because backcasting has, since its origins, had a special focus on energy. Any visioned future must make clear where its energy will come from, and backcasting arose as a response to Lovins' emphasis on the centrality of 'soft' energies, which include not just renewables but the advantages of small scale (Lovins, 1976); the essential point is that, since such a future will be radically different from what we have now, it cannot adequately be forecast from the present (Robinson, 1982). Compared to other methodologies, backcasting thus opens up a stronger understanding of sustainability (Mulder and Biesiot, 1998).I will argue that, underlying energy inputs is a deeper issue of flows and the management of entropy. Energy is conserved, and what flows into any system is what flows out. But, following the Second Law of thermodynamics, it is degraded in the sense that it loses the order which makes it useful (De Rosnay, 1979). At the most basic level, even the solar transition can be seen in this way: since the earth is not a closed system, its own entropy is offset by importing low entropy in the form of solar energy (Georgescu-Roegen, 1975); although conventionally we think we absorb energy from the sun, in reality the energy dissipated by the earth is equivalent to that entering it, the point being that the incoming energy has lower entropy (Penrose, 2010: 78-9). If we moreover remove the artificial distinction between energy and matter, the useable (ordered) input can be termed exergy (negative entropy) (Dincer, 2002). In a future solar economy entropy will be dissipated safely, in contrast to today's flows, where scarce exergy sources (whose extraction moreover degrades local ecosystems) are transformed into pollution and greenhouse gas emission and degrade the wider ea...