Hydroelectric Power Generation and Water Supply Systems
Hydroelectric Power Generation
Resonac Graphite Japan operates hydroelectric power plants in three locations: Aoki, Tokiwa, and Hirotsu.
The Hirotsu and Tokiwa Power station underwent a full renovation of their water turbines, generators, and control systems in 2016 after being in operation for 77 years. Similarly, the Aoki Power station renewed its water turbine, generator, and control systems in 2017 after 63 years of operation. Water way undergo annual inspection and maintenance to ensure smooth, continued operations for the next 80+ years. Sustainable operations of the water supply system are a direct result of diligent and collaborative efforts of Resonac Graphite Japan and the local community.
Aoki Power Station
- Established:
- 1954
- Maximum Output:
- 10,060 kw
- Effective Head:
- 284 m
- Maximum Water Capacity:
- 4.0 m³/s
Tokiwa Power Station
- Established:
- 1941
- Maximum Output:
- 11,400 kw
- Effective Head:
- 69 m
- Maximum Water Capacity:
- 17.8 m³/s
Hirotsu Power Station
- Established:
- 1940
- Maximum Output:
- 20,800 kw
- Effective Head:
- 202 m
- Maximum Water Capacity:
- 11.4 m³/s
Water Supply System
Our water supply system was built between the completion of our Hirotsu Power Station and Aoki Power Station (1939-1954). Operating under authorized water rights, our system efficiently allocates local water resources to fulfill agricultural, household, and power generation needs. As owners of this water supply system, we play a crucial role in its management and operation.
Over the years, the system has become an integral part of the regional infrastructure, and even recognized within the "SDGs Future City Plan" of Omachi City. The social contributions through our water supply system extend to neighboring areas such as Ikeda Town, Matsukawa Village, and Azumino City (Akashina, Hotaka).
The role of the water supply system
The rivers that run through the city of Omachi are situated in a geologically low water-retention area, causing significant amounts of water, including rainfall, to seep underground. This posed challenges in securing a stable water supply for irrigation in the region. However, the water supply system successfully addressed this issue by efficiently distributing water to water-scarce areas through water way and using the channeled water to generate power.
- A 36km-long water way:
- The 36 km long water way transports water to remote areas with water scarcity issues, to be used for household and agricultural purposes.
- A 700m elevation difference:
- Efficient power generation is achieved by leveraging the 700m elevation difference among the three hydroelectric power plants.
- Periods of abundant rainfall:
- During heavy rainfall, the water way are fully utilized to prevent serious damage
- Periods of limited rainfall:
- During periods of water scarcity, top priority is given to water for agriculture over water for power generation
Due to the absence of upstream dams in the Nogu River, the water systems play a crucial role in effectively regulating the intake of water from Aoki Lake and Kisaki Lake, thus minimizing the occurrence of water-related disasters in the area.
The long water way warms the cool water from the Kashima River, and adjusts it to temperatures suitable for irrigation. This temperature regulation has been instrumental in supporting the establishment of numerous agricultural settlements in the Omachi region and brings not only significant benefits to farmers and local businesses but also to the residents of the area.
Resonac Graphite Japan is entrusted with the responsibility of water volume control, maintenance, and overall management of the water way.