Forest and river

Wakayama Aridagawa Cho: Futagawa Small Hydroelectric Power Station

Infrastructure |
Dam Type Reaction Water Turbine
Facility Overview

About The Facility

At the Futagawa Dam upstream of the Arida River, about 0.7 tons of water is constantly being carried out every second to maintain the environment in the downstream area.Aridagawa Town built a town-owned Futagawa Small Hydroelectric Power Station to utilize this unutilized energy.The turbine is a horizontal axis Francis turbine, the maximum output is 200 kW, and the annual predicted power generation is expected to be 1.2 million kWh.The electricity generated is sold to Kansai Electric Power Co., Ltd. based on the "fixed price purchase system of renewable energy" set by the country.

In addition, the obtained electricity sales profit is accumulated as a fund, and it is devoted to the support of the residents' eco activities (assistance for installation of residential solar power generation facilities, environmental education, etc.).

How We Work

Waste reduction, which is the pillar of environmental administration alongside energy, is greatly involved in the construction of this power station.
Although operating collection and transportation for recyclable waste took about 32 million yen per year before, high-quality recyclable waste has been appraised currently due to stationification of gathering sites and thorough separation of garbage by residents and administration, resulting in the revenue of approximately 2.6 million yen per year.
This power station was constructed utilizing the fund which accumulated this revenue and reduced processing cost.

In the future, we plan to build a sustainable mechanism such as further renewable energy projects and support for eco activities of residents so that we can also accumulate electricity sales from small hydropower generation as a fund.
Moreover, as a nationwide advanced example in which the town establishes a power plant alone in the prefectural multi-purpose dam in Japan, its introduction scheme attracts attention.

Contents of the Tour

1. Tour Type: Tour, Visit training, etc.

2. Tour Contents:

  • Overview:

    • Outline description of dam and power station at the upper part of the dam wall(0.5h)

    • Detailed explanation of the power station at the power station directly under the dam(0.5h)

3. Acceptance Conditions:

  • Number of the visitors: A group of 5 or more. Up to about 30 people.

  • Others: Cancel in case of strong wind or rain

4. Access:

40 minutes by car from Fujinami station Kishido line, 2 hours by car from Kansai International Airport

5. Nearby Tourist Spots:

Akagijima (designated as National Important Cultural Landscape and Tanada hundred election), Kanaya Meibusu Onsen (with solar power generation facilities)

Visit Us

Aridagawa Town is certified as "Next Generation Energy Park" by the Agency for Natural Resources and Energy of the Ministry of Economy, Trade and Industry, and there are various renewable energy facilities besides the town-operated Futagawa Small Hydroelectric Power Station we introduced.

In the mountain ranges in the north and south of the town there is a wind farm by private enterprises, and solar power generation facilities have been aggressively installed in town public facilities as well.Information on town solar power plant could be provided upon your request.

Make an inquiry to visit the facility by clicking the button above.
Town-owned Futagawa Small Hydroelectric Power Station
Where We Are
Aridagawa, Arida District, Wakayama Prefecture 643-0542
Introduction Video
Facility Owner Profile
Facility Owner Name
Aridagawa-cho yakuba (town office)
2018-4 Shimotsuno Aridagawa-chō, Arida-gun, Wakayama-ken
Main Business
Local administration, Operation of small hydropower station, Operation of solar power plant, Promotion of renewable energy promotion, Prevention of global warming
Tel: 0737-52-2111
Fax: 0737-52-7822
Accepted Languages
  • Japanese

Dam Type Reaction Water Turbine

Energy > Energy Conversion > Hydraulic to Electric > Hydroelectric Power with Dam > Reaction Turbine


A dam type hydroelectric power generation is a method which uses potential energy of water made by a dam installed in the middle of river flows. A dam is installed in order to stop the flow of water and make a drop in the flow of water. The power plant itself is installed near or bottom of the dam. Basically,  as the water level of the dam goes down, the amount of energy generated will be smaller, because power plants use a head difference from the surface of the dam.

A reaction turbine develops power from the combined action of pressure and moving water. The runner is placed directly in the water stream flowing over the blades rather than striking each individually. Reaction turbines are generally used for sites with lower head and higher flows than compared with the impulse turbines.

Current Situation

This turbine is best suited for higher flow rate and lower head situation.Examples of reaction turbine are Francis turbine, Kaplan and Propeller Turbine, Deriaz Turbine, Tubuler Turbine, etc. Francis turbine is the most preferred hydraulic turbine in the world. In Japan, 70% of hydropower plants use them Also, with about 60% of the global hydropower capacity in the world, Francis turbines are the most widely used type of hydro turbine.

In Use
To use and apply technologies commercially or publicly on the assumption of economic establishment and sustainable operation mainly by companies.
Readiness Technologies Readiness Levels for the DOE
Actual application of technology is in its final form – Technology proven through successful operations.

Technology Scheme

Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy.

As water falls down through the blades of the turbine, it forces them to spin, turning a shaft that is connected to the generator. The turbine converts the kinetic energy of falling water into mechanical energy.

Merit & Strength

1. Available at wide range of water head

It is operated at the water head of 50~800m.

2. Possible to control the amount of flow rate

In Francis turbine, it is possible to control the amount of flow rate.

Demerit & Weakness

1. Complicated maintenance work

As the sand flows along with the water flow to the turbine and collide with the runner, periodic maintenance is required to operate the link mechanism accurately. Its maintenance is disassembling and inspecting complicated link mechanisms, which is complicated and expensive.

(*) Deloitte Analysis section is provided by Deloitte Tohmatsu Consulting Exponential experts to serve helpful information on the subjects discussed. This section content describes generic information related to a technology, product, system or service developed or in use at the facility mentioned at the top. The same description may apply to several facilities.
A image of turbine
Wakayama Aridagawa Cho: Futagawa Small Hydroelectric Power Station
Infrastructure |
Dam Type Reaction Water Turbine
Make an inquiry to visit the facility by clicking the button above.
Town-owned Futagawa Small Hydroelectric Power Station