Planning within a global sight: the structural plan of Ravenna and the emergy storage assessment

It's quite interesting to see how the debate on the limits of growth has vanished from Italian planners real agendas. The more "sustainability" is recurring in local planning rhetoric, the more attention is focused just on the local conditions of environmental health. In order to de-link the ideas of welfare and growth, and to assess the actual influence of plans in resource management, it is useful to adopt a thermodynamic point of view: exergy and emergy are presented as two analogous, necessary and not-sufficient instruments to investigate such themes. From the perspective of global sustainability, plans are not able to deeply influence present consumption rates, determined from different scales of technological, socio-economic and historical premises, but have an influence in large resources stock management. From both the emergy and exergy perspectives, cities are, at the same time, loci of the consumption and accumulation of resources. The concept of emergy storage has been proposed as a tool to assess the accumulations entity, as well as the weight of artificial stocks compared with natural capital stocks, in the same local context of Ravenna, Italy. The results are then compared with emergy flow analysis and practical indications have been produced for the ongoing planning activity. The large natural capital within the Ravenna administrative boundaries turn out to be overexploited, mostly due to the regional role of the city, and some considerations have been produced about the energetic hierarchy of the city.