Technical, financial and urban potentials for solar district heating in Italy

AIRU, the Italian association of district heating, and the Department of Energy of Politecnico di Milano have tried to evaluate the economic, technical, and urban potential of solar district heating in Italy as an efficient and flexible system to spread the use of solar thermal energy in urban areas. This potential has been estimated with the analysis of five case studies of solar thermal integration in district heating networks in the north of Italy: three with a centralized solar plant in existing district heating, one with distributed solar in an existing network, and finally one of a new solar district heating network. These studies, realized in the framework of Solar District Heating Plus project, aim at verifying the technical and economic feasibility of this integration. Besides the more common economic and technical study, a critical analysis looking at the urban aspects of this technology is proposed in order to analyze local potentialities and barriers for this technology. Centralized solar thermal integration has had positive results, while distributed solar rooftop-plants integration turns out to be not economically sustainable. A need for heat planning and heat mapping in urban design emerges as needed to promote and simplify the spread of large-scale renewable-energy plants.