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Hydro power: Pico and Micro Hydropower Systems

Hydro power: Pico and Micro Hydropower Systems

Nakayama Iron Works, Ltd.

Pico & Micro Hydropower System: 
Low-Cost Hydroelectric Generator

Project 2012 1

The “Micro Hydropower System” developed by Nakayama Iron Works Ltd., is a type of hydroelectric system that can produce a few kW to 1 MW of electricity. Until now, the company has installed hydropower plants with a maximum capacity of 49.9kW, and they are now working on a project with a maximum capacity of 420kW. The technology can produce electricity using small streams as main resource for power generation.

The system was developed based on the company's expertise in crushing machines. Keeping the rotation of crushing machines in mind, the company came to understand that this rotation can be used as a power source, which led to the idea of developing micro hydro systems, where the rotation of turbine is converted to electricity. The company's main product is recycling machineries (crushing machines) and they are keen to make the environment clean and safe.

Major Features and Advantages

I. Wide Range of Turbine Types and Capacity
The company offers different types of hydro turbines, e.g. Cross flow turbine, Pelton turbine, Francis turbine, Propeller turbine, Kaplan turbine, Pump turbine etc. They offer turbines with a capacity of a few kW to 1 MW. All turbines work under different range of head and discharge. Based on the site data suggested by the customer, and the geological condition at the site, the company offers suitable turbines for the respective sites.

II. Installation
To install a hydro turbine at any site, it requires flow of water coming from some heights. Geological condition at the site also needs to be considered. A micro hydro system can be installed at a range of different sites including, irrigation canal, rivers (run of river systems), existing dam for irrigation or drinking and water purification plants.

III. On/off Grid
The micro hydro systems can be operated on or off the grid system depending on the user and availability at the site. The system has an electric control panel that switches the energy supply on/off. It provides power independently to homes and small business facilities, or complements other energy sources such as solar photovoltaic and wind.

The company supplies electromechanical equipments of micro hydro systems. To fulfill the requirements of micro hydro, the company has connections with consultants (Seiko Electric, Nishigikogyo, River village etc.), civil companies (local construction companies), electric and control companies (Yaskawa elec., Seiko Electric etc.) and turbine makers from Indonesia and Japan.

Technology Data

Conceivable applications

  • Run-of-river with a minimum head drop of about 2-3 m (even in remote areas). Particular attention shall be paid to the selection of site with potential for high value return and profit.
  • Off-grid electrification development system

Competitive advantage

The micro turbine is a matured technology, so manufacturing of the mechanical parts of the equipment (Pelton Wheel, Cross flow system) can be made either in Indonesia or in Japan, depending on the conditions.

Our company’s competitive advantages are as follows, which we have got through joint research with Kyushu University, and other manufactures.

  1. Low cost to manufacture micro turbine power system.
  2. Reliability and stability of the electric control panel system, which is based on the multiple experiences accumulated through the development of ON/OFF grid systems for solar and wind power generators.
  3. Reduced cost for power generation by this micro turbine power system (approx. 1,000,000 JPY/kW), which is significantly low, comparing with the cost by conventional power generation systems.


Introduction of small hydro power generation installation of less than 200kW capacity as an ON/OFF grid system.

OFF Grid
Example A: Application of the micro hydro turbine power system in household network.
                          Off Grid 1

Example B: Combined application of photovoltaic power system and micro hydro turbine power system in household network.

Off Grid 2

ON Grid
Electric grid is an interconnected network of several power sources, such as solar, wind, and hydro electric plants. It is necessary to undertake joint research with researchers, manufacturers, and PLN. The micro hydro turbines are applicable to rural areas.
 On Grid

Technical maturity

Small community development projects in Japan:
– 200 W Pico hydro with Pelton wheel (2012)
 Project 2012 1
Project 2012  2

– 15 kW Mini hydro integrated with Pelton wheel (10 kW) and Cross flow type (5 kW) systems (2014).

Project 2014

Based on conventional technology, we started to develop small hydroelectric power systems using water conduit in 2012. Later, in collaboration with the Indonesian Small Hydropower Association, a more affordable technology was established and successfully implemented.

Additionally, we have been proceeding with a small hydropower project in India since 2012 with JAG Seabell co., Ltd. through OEM to provide turbines for hydro power generation. There are a lot of potential sites overseas that can be considered for power generation using ultra-low head technology. More irrigation channels are located in those sites, comparing with Japan.

*For more information on the JAG Seabell co., Ltd.’s Micro hydropower system, please check here.

Conceivable risk

ON Grid electrification system difference from country to country.

Information on patent related to this technology

Patent 2014-003848

Company Data

Name Nakayama Iron Works, Ltd.
Address 2246-1 Amagu, Asahimachi, Takeo City, Saga
Capital JPY 86,500,000
Contact person Mr. Yoshinobu WATANABE / Ms. Sayaka OKA
Tel.: +81-954-22-4171
Fax: +81-954-23-0691
Number of employees 150 (15 for interntional operation)
Date of company foundation June, 1908
The type of business Design and manufacture of:
– Stone crushers, screens, sand making machines,
belt conveyors and other related equipment for the
quarry/mining and recycling industries
– Mobile and stationary rock crushing plants, asphalt/
concrete recycling plants
– Soil remediation equipment and dust suppression
– Small hydroelectric power generation equipment and
Overseas offices NCSS (Nakayama Crushing Services Singapore Pte, Ltd)

Modality of business transaction

Manufacture of screens and belt conveyor modules
Manufacture of small hydroelectric power generation equipment and systems

Export of product
Dual powered mobile crushing equipment and stationary plants
On-Off grid system integration for small hydro power



The control system of “on-off grid” is operated by two ways to switch on/off the energy supply.

The system, shown in the bottom of the diagram, is a simpler one of the two, and it is a
combination of power conditioner and diode, which is relatively common for solar power
production. However, this method only provides a protection circuit, and there is no power
control in this system.

Another method, illustrated in the upper part of the picture is based on a compact wind power generating system. This system can maximize output power by monitoring the rotation speed and torque of the turbine.

Regarding the orders and purchases, customers can order either/ both of these two control systems. It can be flexible, according to clients’ requirements, for instance initial cost, amount of power generation and implementation process.

This Japanese advanced technology will enable us to easily build small hydroelectric power systems without rotation control.

What’s new?

Compact Hydropower systems:

The company also offers compact hydro power systems, which is their new innovation. With the help of Seiko Electric and Taiko Kikai ltd., Nakayama Iron works has developed a compact hydropower systems. Everything is inside a container which works as a power house. Inside the container all the mechanical and electrical equipments are installed and the necessary wiring has been done.

Advantages of compact micro hydro systems:

  • Simple and easy installation
  • Stable output
  • Low cost
  • Movable


Fig. 1. Layout of compact micro hydro system.



Contact Person(s)

Mr. Yoshinobu WATANABE / Ms. Sayaka OKAE-mail:

*Please mention that you saw UNIDO's website when making the first contact with the company.

Registered Category

  • Energy Technologies : Renewable energy