Over 126 million people visit Onsens annually, spending considerable amount of money at spas, hotels, restaurants, and shops at hot springs. Because of the significant economic activities related to tourism, local communities didn’t think that Onsen business and geothermal power plants could co-exist.
They were concerned that deployment of geothermal power plants would change the quality and compositions of spring water, which contains a lot of organic matter that is known to provide health and beauty benefits. Most importantly, the community feared that geothermal power plants would dry up their precious spring water wells.
Their concerns were eliminated when binary geothermal power plants were introduced.
Nation’s First Binary System Installed at an Evacuation Site
Yumura Onsen in Shinonsen town, Hyogo prefecture, installed two 20 kW (a total of 40 kW) binary geothermal power plants at Yakushiyu, a day spa, which also is a state designated evacuation site where people in the community can assemble in the case of emergencies or disasters.
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| “Onsen” Binary Geothermal Systems (2 x 20 kW), Credit: The Town of Shinonsen |
Binary geothermal power plants, or “Onsen” Binary plants, use chemical fluids known as a second liquid (e.g., Isobutene and n-Pentane) that boils at a lower temperature than water. Hot spring water passes through a heat exchanger and heats up the second liquid in a closed loop. Heat from the geothermal water causes the secondary fluid to flash to vapor, which then drives the turbines, and subsequently the generators. The vapor is condensed back to liquid and begins the cycle again. Because this is a closed-loop system, virtually nothing is emitted to the atmosphere....Read More Here