Survey on the Operation of the District Energy Supply System in Japan According to Secular Change

Abstract

Japan aimed for independent energy provision of large-scale energy consumers and energy efficient supply, so it actively introduced the District Energy System (DES) in the 1970s. A total of 133 sites (2 sites are unclear) are currently in operation, with 23 DESs established since 2000, and 110 sites consisting of superannuated facilities that are more than 20 years old. The purpose of this study is to compare and analyze the operational status of the DESs according to secular change, by identifying the supply area, the primary energy usage, and the utilization of renewable energy. As of 2003, 164 sites were in operation, and as of 2015, there were 133 sites. About 83% of the 133 sites were obsolete, being – more than 20 years old. About 87% areas showed lowered ratios of input primary energy in 2015 compared to that in 2003. The rate of operation of the main DES energy production system, cogeneration, has declined significantly, and the number of areas that use a current system rather than operate in cogeneration, has increased. This may have been due to the reduction of end use demand by the aging of the cities and the deterioration of the facilities. Therefore, it is necessary to suggest a new direction for the DES in preparation for the aging of their localities.