Geothermal Power Generation

Japan has the third largest volume of geothermal resources in the world. However, there are still a very small number of power plants using geothermal energy in this country.

Power generation using wind, sunlight and other natural energy sources are characterized in that the time slot for power generation is limited and the capacity varies considerably, depending on the weather and the season.

In contrast, geothermal power generation excels in stability since it generates a fixed amount of electricity year round. Geothermal energy has been spotlighted in recent years as a renewable energy source for base load power generation.


Generating Power from the Energy of Magma

Geothermal power generation utilizes the thermal energy of magma underneath the ground in volcanic areas. At a shallow depth below a volcano, lie hot magma reservoirs. Their high temperature may heat the rocks and water around them to form geothermal reservoirs. In geothermal power generation, the steam obtained from these reservoirs rotates turbines to generate electricity.


Flash Steam System

A steam separator separates steam only once from geothermal fluid consisting of steam flashed under the ground and hot water. That separated steam turns turbines. Most of the geothermal power plants in Japan use this system. The hot water after separation is returned to underground reservoirs.

Process Towards Start of Operation in Geothermal Power Generation Project

RENOVA aims to pursue the long-term sustainable development of geothermal resources in harmony with local hot springs and the natural environment.

To undertake geothermal reserves surveys, RENOVA will hold continuous discussions with local stakeholders in a bid to gain their understanding.

Before conducting any subsequent survey as a result of the survey findings, RENOVA will again speak with local stakeholders to seek their understanding.

  1. Surface survey(in years 1 to 2)

    Surveying geothermal manifestation

    • Geological and geochemical surveys
    • Geophysical exploration
    • Selection of targets
  2. Underground exploration and evaluation(in years 3 to 5)

    Examining geothermal reservoirs

    • Well survey
    • Fumaroles test
    • Overall analysis
  3. Environmental impact assessment(in years 6 to 9)

    Conserving the environment and complying with laws and ordinances

    • Environmental impact assessment
    • Hot springs impact assessment
    • Licenses and approvals
  4. Construction(in years 10 to 12)

    Building a geothermal power plant

    • Design
    • Construction
    • Trial operation
  5. Operation(in year 13 and later)

    Operating a geothermal power plant

    • Operation
    • Maintenance
    • Reservoir monitoring