In his first policy speech, it wasn’t solar or offshore wind power that Prime Minister Ishiba mentioned as a renewable energy source with high potential. As Japan’s 102nd premier took office in October 2024, he counted geothermal power among promising energy sources to address Japan’s energy constraints.

In a major policy speech by a Japanese leader, the choice of geothermal energy, which uses underground heat to drive turbines, was unusual. Despite its well-known potential, geothermal energy development has barely progressed in Japan even after the feed-intariff (FIT)-driven renewables boom was unleashed in 2012.

Most of the capacity added since then has been in solar power, and the big bet for the 2030s is on offshore wind. Meanwhile, biomass and hydro have enjoyed mild success. But geothermal?

Since Ishiba’s inauguration, however, geothermal energy has gained momentum. In November, METI and MoE unveiled a policy package to bolster developments in the sector. The package includes the “Geothermal Frontier Project” to expand geothermal power using conventional technologies. Officials also set up a public-private forum to promote next-generation geothermal technologies, with more than 70 companies and groups joining as members.

Buoyed by increased demand for clean electricity, the sector is on the cusp of a technological breakthrough. Some of the emerging tech is forecast to increase Japan’s geothermal potential by more than four-fold. So, what’s different this time?