the impact of renewable energy and energy effi-cient technologies, what to choose in case of limited supportive actions: a case study

research topics dealing with the application of the markal model have been quite common in the last 20+ years. every new paper has added new insight into the potential of using such a model for a variety of purposes. not only global but also local applications have shown both limits and benefits when dealing with manifold energy-environmental-resources optimal management. the aim of this work is to strengthen the idea that such models, even with the limits that have been underlined, can continue to contribute as a valid tool to assist local policy makers to have a better/ objective idea of the impact and potential of certain actions. besides, it provides a non-biased tool in case incentive resources run out and a diverse portfolio of actions to achieve set environmental targets does exist. in times where economic crises strike every sphere of political and civil actions, it is more important to be able to rely on objective instruments to support choices at every level. thus the local level becomes more and more strategic. the paper deals with an application of the standard markal model to a northern italian province (190 municipalities and half a million people), in order to give useful circumscribed information on the results coming out from a simple, but interconnected, optimized energy model, when a previous skimming has been performed to identify the target actions of possible incentives. the choice is to benefit only few actions, in order to make the effect of it keener. in this case the two competing actions in the residential sector are (i) fostering more efficient buildings vs. (ii) additional support for renewable technologies. the scope of the applied research is to give economic and environmental indexes useful to decide where to invest the limited local resources. for this scope different energy development scenarios have been analyzed and their performance indicators identified. developing consistent local energy plans, by using a consolidated bottom up approach and by a combination of long-term planning strategy based upon technological development and replacement is still far from a routine procedure from a local policy makers' standpoint. the study focuses on the thermal use of energy in the residential sector, being it the main target of the epb directive (2002/91/ec), whose impact, along with the role of renewable energies, are investigated with and without a public support. also, the role of the public commitment is highlighted in terms of effective policy that could drive the technological competition and the real estate market to achieve the optimal configuration of the energy system (the lowest cost and the lowest environmental impact), by means of subsidies for thermal solar and biomass technologies.