Hatchobaru Power Plant emitting

 Driving through Kokonoe Town in Oita Prefecture with the Kuju mountain range in view, a facility releasing thick white steam suddenly appears. It is the Hatchobaru Geothermal Power Plant, Japan’s largest geothermal plant with an output of about 110,000 kW.

“Most of the equipment dates back 40–50 years to when the plant opened, yet it still operates stably 24 hours a day, 365 days a year,” says plant manager Hideki Yoshikai (53). The first unit began operation in 1977, the second in 1990, and together they continue to supply electricity equivalent to 192,000 households.

Geothermal power generates electricity by extracting high‑temperature steam and hot water from 1,000–3,000 meters underground, separating the steam, and using it to turn turbines. Yoshikai says the plant can “keep running for another 50 years.”

Among renewable energy sources, geothermal power is not affected by weather like solar or wind. Because Japan relies heavily on imported energy and has low energy self‑sufficiency, geothermal is seen as a highly promising “purely domestic” energy source.