Mitsui Fudosan begins Japan's first closed-loop geothermal demonstration

Mitsui Fudosan, Shin Nippon Science, and Japan New Energy have commenced a demonstration project for next-generation geothermal power in Ibusuki, Kagoshima Prefecture. The project utilizes a coaxial double-pipe closed-loop system, which circulates water through sealed pipes to harvest underground heat without extracting natural hot water or steam. This method aims to minimize environmental impact and reduce dependence on specific geological conditions like steam reservoirs.

Drilling for the project has been completed, with demonstration plant construction and operation expected in the 2027–2028 period. The consortium aims for commercialization as early as fiscal year 2029, which would mark a domestic first. This technology is seen as a way to expand Japan's geothermal potential, which currently accounts for only 0.3% of its power generation despite the country holding the world's third-largest geothermal resources.

Separately, Taisei Corporation is conducting feasibility studies on using supercritical CO2 as a heat transfer fluid in geothermal systems. These advancements align with Japan's national energy goals to significantly increase geothermal capacity by 2040 and 2050.