Wakura Onsen, located in Nanao City, Ishikawa Prefecture, is one of Japan’s best high-end hot springs districts. It is also the home of Niji To Umi, one of the hot springs inns owned by the Kagaya Group. It is there that the “Project to Create an Independent and Distributed Energy System Through Digital Grid Router-Enabled Electrical Power Interchanges” selected by the Ministry of the Environment for FY2014 to FY2016 was jointly implemented by Tateyama Kagaku Industry Co., Ltd., one of our corporate investors, and what was then the Abe Lab at the University of Tokyo.
In addition to solar power, another source of renewable energy available to Wakura Onsen is the waste heat generated from its ~92° centigrade hot springs. In this pilot project, we utilized DGRs to conduct electrical power interchanges between three different facilities on the inn’s grounds, each equipped with a different energy source, in order to demonstrate an electrical system capable of operating independently even in a disaster. These sources were a binary power generator utilizing waste heat from the hot springs, biodiesel generators, a solar power system and storage batteries, respectively.
These three facilities were Niji To Umi’s main building, its energy building, and the office building of the company that manages the inn. By utilizing the multiple sources listed above at multiple electrical demand facilities, we created a system capable of operating independently during a disaster.
The DGRs installed at these three locations each tag their electricity and record how much of which electricity is used during electrical interchanges. At the same time, they switch among electricity resources depending on the demand and priority of which generator to use.