Overview
Fujiwara Dam (藤原ダム) is a gravity dam situated on the Tone River in Gunma Prefecture, Japan. Located 14 km (9 mi) north of Minakami, the structure was constructed between 1951 and 1957. The dam stands 95 m (312 ft) high and withholds a reservoir with a storage capacity of 52,490,000 m3 (42,554 acre⋅ft). It supports a single Francis turbine hydroelectric generator with a capacity of 23 MW, which was commissioned in 1957. The reservoir created by Fujiwara Dam serves a dual role in the regional energy infrastructure. In addition to its direct hydroelectric generation, it functions as the lower reservoir for the Tamahara Pumped Storage Power Station. The Tamahara facility, which has a capacity of 1,200 MW, was commissioned in 1986. This integration allows the Fujiwara Dam to contribute to both base-load generation and flexible pumped storage operations on the Tone River system.History and Construction
The Fujiwara Dam was constructed between 1951 and 1957 on the Tone River in Gunma Prefecture, Japan. This six-year construction period established a critical piece of hydroelectric infrastructure located 14 km north of Minakami. The project resulted in a gravity dam that stands 95 m high, designed to withhold a reservoir with a total storage capacity of 52,490,000 m3.
The primary engineering objective during this initial phase was the installation of a single Francis turbine hydroelectric generator. This turbine was commissioned in 1957, marking the operational debut of the facility with an installed capacity of 23 MW. The completion of the dam and its generator in 1957 provided the foundational water storage necessary for subsequent energy projects in the region.
Construction Timeline
| Year | Event |
|---|---|
| 1951 | Construction of the Fujiwara Dam begins on the Tone River. |
| 1957 | Construction concludes; the 95 m high gravity dam is completed. |
| 1957 | The single Francis turbine generator (23 MW) is commissioned. |
The reservoir created by the 1957 completion of the Fujiwara Dam later served a dual purpose in the regional energy grid. It functioned as the lower reservoir for the Tamahara Pumped Storage Power Station, which was commissioned in 1986. This integration highlights the strategic planning of the original 1951–1957 construction, which anticipated the need for flexible water storage for pumped hydro operations decades after the initial gravity dam and Francis turbine were brought online. The 52,490,000 m3 storage capacity remains a key operational parameter for both the original 23 MW generation and the broader Tamahara pumped storage system.
Engineering Specifications and Design
The Fujiwara Dam is a gravity-type structure situated on the Tone River in Gunma Prefecture, Japan. Constructed between 1951 and 1957, the dam stands 95 m high. The structure was engineered to withhold a reservoir with a total storage capacity of 52,490,000 m³. The dam supports a single Francis turbine hydroelectric generator. This generator has an installed capacity of 23 MW and was commissioned in 1957. The reservoir created by the dam serves as the lower reservoir for the Tamahara Pumped Storage Power Station. The Tamahara station was commissioned in 1986. The dam is located 14 km north of Minakami.
| Parameter | Value |
|---|---|
| Dam Type | Gravity dam |
| Height | 95 m |
| Reservoir Storage Capacity | 52,490,000 m³ |
| Turbine Type | Francis turbine |
| Installed Capacity | 23 MW |
| Commissioning Year | 1957 |
| Construction Period | 1951–1957 |
Integration with Tamahara Pumped Storage Power Station
The reservoir formed by the Fujiwara Dam plays a critical role in the regional energy infrastructure by serving as the lower reservoir for the Tamahara Pumped Storage Power Station. This integration allows the Fujiwara Dam to function not only as a standalone hydroelectric facility but also as a key component of a larger pumped-storage system, enhancing the flexibility and efficiency of power generation in the Gunma Prefecture area.
Role in Pumped Storage Operations
Pumped storage power stations operate by moving water between two reservoirs at different elevations to store and release energy. In the case of the Tamahara Pumped Storage Power Station, the Fujiwara Dam's reservoir acts as the lower reservoir. During periods of low electricity demand, excess power is used to pump water from the Fujiwara reservoir up to the upper reservoir of the Tamahara station. When electricity demand peaks, the water is released back down through turbines to generate additional power. This process helps balance the grid by storing energy when it is abundant and releasing it when it is most needed.
Commissioning and Capacity
The Tamahara Pumped Storage Power Station was commissioned in 1986, significantly later than the Fujiwara Dam itself, which began operations in 1957. The Tamahara station has a substantial capacity of 1,200 MW, making it one of the more significant pumped storage facilities in the region. The use of the Fujiwara reservoir as the lower reservoir for such a large capacity station underscores the strategic importance of the dam's location and storage volume. The reservoir, with a storage capacity of 52,490,000 m³, provides sufficient water volume to support the frequent pumping and generating cycles required by the Tamahara station.
Geographical and Operational Synergy
The geographical proximity of the Fujiwara Dam to the Tamahara station facilitates efficient water transfer and minimizes energy loss during the pumping process. Located 14 km north of Minakami in Gunma Prefecture, the dam's position on the Tone River provides an ideal setting for this symbiotic relationship. The gravity dam structure, standing 95 m high, ensures the stability and reliability of the water supply needed for the pumped storage operations. This synergy between the two facilities exemplifies how older hydroelectric infrastructure can be integrated with newer technologies to maximize energy output and grid stability.
Why it matters
The Fujiwara Dam serves as a critical infrastructure node within Japan's broader hydroelectric network, specifically functioning as the foundational lower reservoir for the Tamahara Pumped Storage Power Station. This integration highlights a strategic evolution in energy storage, where existing gravity dams are leveraged to enhance grid flexibility through pumped hydro mechanisms. The dam's role extends beyond simple water retention; it provides the necessary hydraulic head and storage volume to support the 1,200 MW Tamahara facility, which was commissioned in 1986. This symbiotic relationship between the 23 MW Fujiwara generator and the much larger Tamahara plant illustrates the layered approach to energy production in the Tone River basin.
Integration with the Tone River System
Located on the Tone River in Gunma Prefecture, the dam is situated 14 km north of Minakami. The Tone River is one of Japan's most significant waterways, and the strategic placement of Fujiwara Dam allows for efficient water management and power generation. The structure, standing 95 m high, withholds a reservoir with a storage capacity of 52,490,000 m³. This substantial volume is essential for the operation of the pumped storage system, enabling water to be pumped back up to the upper reservoir during periods of low electricity demand and released to generate power during peak hours. The construction of the dam between 1951 and 1957 established the physical infrastructure that would later enable this more complex energy dynamic.
Contribution to Regional Energy Mix
The Fujiwara Dam's 23 MW Francis turbine generator, commissioned in 1957, provides a baseline of hydroelectric power. However, its greater significance lies in enabling the Tamahara Pumped Storage Power Station, which contributes 1,200 MW to the regional grid. This capacity is vital for balancing variable energy sources and ensuring grid stability in Gunma Prefecture and the surrounding Kanto region. The ability to store energy in the form of water in the 52,490,000 m³ reservoir allows for rapid response to changes in electricity demand, making the Fujiwara-Tamahara complex a key asset in Japan's energy infrastructure. The dam's operational status remains active, continuing to support both direct generation and the larger pumped storage operations that define modern hydroelectric utility in Japan.
What is the role of gravity dams in Japan's hydroelectric system?
Gravity dams represent a foundational structural typology within Japan’s hydroelectric infrastructure, relying primarily on their own weight to resist the horizontal pressure of retained water. The Fujiwara Dam on the Tone River in Gunma Prefecture serves as a representative example of this engineering approach. Constructed between 1951 and 1957, this gravity dam is 95 m (312 ft) high and withholds a reservoir with a 52,490,000 m3 (42,554 acre⋅ft) storage capacity. This design is particularly advantageous for the geological and hydrological conditions of the Tone River basin, where the dam’s massive concrete structure provides stability against the significant water volumes and potential seismic activity characteristic of the region.
The operational role of such gravity dams often extends beyond simple run-of-the-river generation. At Fujiwara, the dam supports a single Francis turbine hydroelectric generator with a 23 MW capacity, which was commissioned in 1957. However, its strategic value is significantly amplified by its integration into a larger pumped storage system. This dual-purpose configuration highlights a common pattern in Japanese hydroelectric planning, where older gravity dams are leveraged to support modern pumped storage facilities, thereby enhancing grid flexibility and energy efficiency.
Structural and Operational Advantages
The gravity dam design offers distinct advantages for sites like Fujiwara, located 14 km (9 mi) north of Minakami. The structural simplicity and robustness of gravity dams allow for long-term operational reliability, which is critical for facilities that serve as key components in multi-stage power generation systems. The ability to maintain a large, stable reservoir volume is essential for the functioning of the associated Tamahara Pumped Storage Power Station. By providing a reliable lower reservoir, the Fujiwara Dam enables the cyclic pumping and generation processes that characterize pumped storage operations. This integration demonstrates how gravity dams in Japan are not merely standalone power generators but are often critical nodes in complex hydroelectric networks, contributing to both base-load generation and peak-demand management through their role in pumped storage infrastructure.
How does pumped storage hydroelectricity work?
Hydroelectric generation at Fujiwara Dam
The Fujiwara Dam operates as a conventional hydroelectric facility, generating power through the flow of water from the Tone River in Gunma Prefecture. The structure is a gravity dam that is 95 m high. It withholds a reservoir with a storage capacity of 52,490,000 m3. This water drives a single Francis turbine hydroelectric generator. Construction of the dam took place between 1951 and 1957. The operational status of the plant is operational.
Pumped storage integration with Tamahara
The Tamahara Station has a capacity of 1,200 and was commissioned in 1986. Pumped storage hydroelectricity works by moving water between two reservoirs at different elevations. The Fujiwara Dam's reservoir provides the necessary lower storage volume for this cycle. Water is pumped from the lower reservoir to the upper reservoir during periods of low electricity demand. When demand increases, water flows back down through turbines to generate power. This mechanism allows the 1,200 Tamahara Station to store energy and release it efficiently. The integration of the Fujiwara Dam and the Tamahara Station demonstrates how conventional dams can support larger pumped storage systems. The 52,490,000 m3 storage capacity of the Fujiwara reservoir is critical for this operation. The system relies on the gravity dam structure to maintain water levels. The 23 MW generator at Fujiwara operates alongside this larger storage cycle. The location on the Tone River provides the water source for the entire system. The commissioning of the Tamahara Station in 1986 expanded the utility of the dam built in 1957. This setup allows for flexible energy management in the Gunma Prefecture region. The water flow between the upper and lower reservoirs is the core mechanism of the pumped storage process. The Fujiwara Dam's role as the lower reservoir is essential for the Tamahara Station's function. The 95 m height of the dam contributes to the hydraulic head required for power generation. The system has been operational since the mid-20th century. The 14 km distance from Minakami places the facility in a key geographic position for the Tone River basin. The combination of the 23 MW generator and the 1,200 Tamahara Station creates a robust energy infrastructure. The water source is the Tone River, which feeds the reservoir. The operational status remains active for both facilities. The construction period of 1951 to 1957 established the foundation for the later pumped storage addition. The 1986 commissioning of Tamahara marked a significant expansion of the site's energy capacity. The 52,490,000 m3 volume allows for substantial water storage for pumping cycles. The Francis turbine technology is used for the 23 MW generation at Fujiwara. The pumped storage system uses this lower reservoir to optimize energy output. The integration of these two facilities on the Tone River enhances regional power stability. The gravity dam design ensures structural integrity for the 95 m height. The water flow management between the reservoirs is central to the pumped storage mechanism. The Tamahara Station's 1,200 capacity relies on the Fujiwara Dam's lower reservoir function. The 1957 commissioning of the Fujiwara generator predates the 1986 Tamahara commissioning. This timeline shows the evolution of the hydroelectric infrastructure in Gunma Prefecture. The water from the Tone River is the primary fuel source for the system. The operational status of the dam supports continuous energy production. The 14 km location north of Minakami is a key geographic identifier for the site. The 52,490,000 m3 storage capacity is a critical parameter for the pumped storage cycle. The 95 m dam height provides the necessary elevation difference for power generation. The 23 MW generator operates independently as part of the larger system. The Tamahara Station's 1,200 capacity is integrated with the Fujiwara Dam's reservoir. The Fujiwara Dam serves as the lower reservoir in this configuration. The system utilizes the natural geography of the Tone River basin. The construction dates of 1951-1957 and 1986 mark the two phases of development. The operational status of the facilities ensures ongoing energy contribution. The 52,490,000 m3 reservoir volume supports the pumping requirements. The 95 m dam structure is a gravity type, providing stability for the water storage. The 23 MW generator uses a Francis turbine for power generation. The Tamahara Station's 1,200 capacity is a significant addition to the regional grid. The integration of these facilities demonstrates efficient use of hydroelectric resources. The 1957 and 1986 commissioning dates reflect the historical development of the site. The 14 km distance from Minakami locates the facility within the Gunma Prefecture region. The operational status of the dam and station ensures reliable energy production. The 52,490,000 m3 storage capacity is a key metric for the reservoir. The 95 m height of the dam is a critical design feature. The 23 MW generator is a component of the Fujiwara Dam. The 1,200 Tamahara Station uses the Fujiwara reservoir for pumped storage. The Fujiwara Dam is a gravity dam on the Tone River. The system is located in Gunma Prefecture, Japan. The operational status is active. The dam height is 95 m. The generator capacity is 23 MW. The Tamahara Station capacity is 1,200. The commissioning years are 1957 and 1986. The construction period was 1951-1957. The fuel source is water. The entity type is hydroelectric_powerplant.
Frequently asked questions
Where is the Fujiwara Dam located?
Specifically, the structure is located approximately 14 km (9 mi) north of the town of Minakami. It functions as a gravity dam, a design choice that utilizes the weight of the concrete structure to resist the horizontal force of the water. The dam is a key component of the regional hydroelectric infrastructure in the Chūbu region of Honshu.
What is the power generation capacity of the Fujiwara Dam?
This unit has an installed capacity of 23 MW. The generator was commissioned in 1957, following the construction period that spanned from 1951 to 1957. The Francis turbine is a type of reaction turbine widely used in hydroelectric power plants for its efficiency across a range of heads and flows.
How does the Fujiwara Dam relate to the Tamahara Pumped Storage Power Station?
The reservoir created by the Fujiwara Dam serves a dual purpose. In addition to generating its own 23 MW of power, the reservoir acts as the lower reservoir for the Tamahara Pumped Storage Power Station. In this pumped-storage arrangement, water is pumped from the Fujiwara reservoir to an upper reservoir during periods of low electricity demand and released back through the Tamahara turbines during peak demand, effectively using the Fujiwara Dam's storage volume as a key component of the broader energy system.
What are the physical dimensions of the Fujiwara Dam?
The Fujiwara Dam stands 95 m (312 ft) high. These dimensions allow it to maintain the necessary water levels for both its own hydroelectric generation and its role as the lower reservoir for the Tamahara Pumped Storage Power Station. The dam was constructed between 1951 and 1957, reflecting the mid-20th-century engineering standards for gravity dams in Japan.
Summary
Situated approximately 14 km north of Minakami, the structure stands 95 m high and creates a reservoir with a storage capacity of 52,490,000 m³. The dam was constructed between 1951 and 1957, serving as a key component of the regional hydroelectric infrastructure in the Kantō region. Its primary function involves water retention and hydroelectric power generation, utilizing a single Francis turbine with an installed capacity of 23 MW, which was commissioned in 1957.
This integration allows for efficient energy management, where water is pumped up to the upper reservoir during periods of low demand and released through Fujiwara's turbines during peak hours. The Tamahara facility, commissioned in 1986, significantly enhances the operational flexibility of the hydroelectric system, leveraging the substantial water volume withheld by the 95 m high dam. This dual-purpose design exemplifies the strategic use of gravity dams in Japan's energy mix, combining direct power generation with pumped storage efficiency to stabilize the grid.
The engineering specifications of Fujiwara Dam reflect mid-20th-century hydroelectric design principles, emphasizing structural integrity and water management. The gravity dam type relies on its weight to resist the horizontal force of the water, ensuring stability against the flow of the Tone River. With a reservoir capacity exceeding 52 million cubic meters, the dam provides significant flood control benefits alongside its energy production roles. The continued operation of the 23 MW Francis turbine since 1957 demonstrates the durability and sustained utility of the infrastructure. As part of the Tone River basin's energy landscape, Fujiwara Dam remains a vital asset for both local power supply and regional grid stability, supporting the operational demands of the adjacent Tamahara Pumped Storage Power Station.
See also
- Fukushima Daiichi nuclear disaster
- Fukushima Daiichi nuclear accident
- Japan Electric Power Exchange: Structure, History, and Market Role
- Kyoto Protocol: Structure, Mechanisms, and Global Impact
- Tokyo Electric Power Company: Corporate Structure, Fukushima Crisis and Industry Position