power plant
design and construction by Fuji Electric Co., Ltd.

Design and construction by Fuji Electric Co., Ltd.

geothermal power generators

Five power generators using hot spring heat are installed on the mountain side of the Ryukyoso lodge.

Hot spring gushing out from the well is separated into steam and hot water by a separator, and generators #1, #2 and #3 generate electricity by steam, and generators #4 and #5 generate electricity by hot water.

capability and surplus of geothermal power plant

Each generator has capability of 135 kW, and the actual output is 125 kW per each unit. Since there are five generators, the total output makes 625 kW.

facility of the lodge is planned to use electricity within 165 kW, so, the remaining 460 kW can be supplied to the surrounding consumers such as inns, shops and households etc.. Thus, the Ryukyoso lodge provides function of “microgrid” by using renewable energy of geothermal heat.

heat source circulates underground

Hot spring erupts from 800m below ground, and after the gushing steam and hot water are used, the flow of these heat sources are drawn and returned to the ground by a circulation well dug to 300m below ground.

mechanism of power generation


Generator Catalog, posted from the site of Energy Business Headquarters, Energy Development Department, Daiichi Jitsugyo Co., Ltd. In Japan, which has global partnership with Access Energy in U.S.A.

Geothermal power plant of the Ryukyoso lodge has a binary power generation mechanism. The heat from the hot spring is first transferred to a CFC alternative (a liquid called R25Fa that easily vaporizes even at low temperatures) by the closed system of heat exchanger, and second, heated CFC alternative boils up and becomes steam which turns the turbine of the power generators.