Utilization of Sewage Heat as Part of Environmentally Conscious Urban Development - October 1996 Namekawa City, Toyama Prefecture

Utilization of Sewage Heat as Part of Environmentally Conscious Urban Development - October 1996 Namekawa City, Toyama Prefecture

In Japan in the 1990s, concerns about global warming and the depletion of energy resources increased, and the reuse of energy and the utilization of local resources became policy issues. The effective use of "sewage heat" was the focus of attention. Namekawa City in Toyama Prefecture has undertaken a demonstration experiment of a "sewage heat utilization system" that utilizes the heat contained in urban wastewater. Sewage stores low-temperature thermal energy derived from people's daily lives and industrial activities, and this energy is used for air-conditioning and hot water supply in buildings. The New Energy and Industrial Technology Development Organization (NEDO) participated in this project, making it an advanced effort through collaboration between the local government and the national government. Technically, heat is extracted and reused on a practical level by combining heat exchangers and heat pumps, contributing to both energy conservation and reduction of CO₂ e
missions. At the time, there were still issues to be addressed in terms of equipment costs and management, but even so, the project attracted nationwide attention from the perspective of recovering unused energy in urban areas. Namekawa City's efforts have since been recognized as a pioneering example of district heat supply and the use of area-wide energy, and should be remembered as a step forward in building a sustainable urban model.