A review of Italian district heating

District heating is a way to provide heat to residential users, commercial buildings and industrial services, for space heating, hot water and process heat, through a heat distribution network. The distribution system is powered by the heat of one or more sources, such as dedicated heat production systems based on renewable energy and fossil fuels or waste from industrial systems. Large District Heating systems can meet the heat demand of large urban areas and include a range of heat production facilities, transmission pipelines and distribution networks, connecting thousands of consumers. In this review we want to highlight the situation of district heating first at a European level and then at an Italian level, through data on the diffusion, on the heated volume and on the relative costs of this technology.