This article presents a study on a waste-to-energy (WtE) technology and its application for district heating (DH) at a particular site in the city of Avil es (Spain). The study is based on the recovery of surplus heat from a cooling facility at a steel mill in the neighborhood of Avil es. The thermal energy demanded by the potential users, which include apartment blocks, a hotel, and a sport, and spa center, has been estimated in 1.1 MW in winter and 0.5 MW in summer, during daytime. The process proposed has two main stages: first, surplus hot air is collected by hoods in the factory and circulated through a heat exchanger, and second, the resulting hot water is transported to the destination sites by means of a new insulated pipeline network. Total technical costs (not including financial nor insurance costs) have been estimated in 660 ke. The study raised a number of key issues such as the necessity of simulation tools to predict the process performance when modifying the plant scheme or the convenience for additional economical or social incentives, like those related to the current municipal project denoted as "Isla de la Innovaci on." V C