In order to promote the use of renewable and unused energy at the local level to achieve decarbonization, a local energy use plan that takes into account energy supply and demand balance on hourly basis and de-mand location necessary. Therefore, this study calculated the decarbonization effect by assuming heat supply scenarios of unused heat from waste incineration plant based on the future vision around the waste incineration plant, and analyzing the waste heat supply and demand on a monthly and hourly basis for a case study area, Koshigaya City, Saitama Prefecture. The results showed that by locating hospitals and greenhouses which have certain heat demand at night or in summer in the surroundings of the waste incineration plant, more unused heat can be utilized and the decarbonization effect by replacing fossil fuels can be larger.