Three Types (Pelton, Screw, Undershot) of Small Hydropower Generator


3 Types of Small Hydroelectric Generators with 10kW Power in maximum for Various Head at Low Initial Cost

Our small-scale hydroelectric power generators that utilize river water can be optimally selected and applied corresponding the locational conditions such as water flow and head. The range of power generation output is 10kW or less generated by relatively small-capacity turbine. Since our small-scale generators can be decentralized in immediate surroundings of rivers and canals, the equipment can be installed at a lower cost compared to large-scale types. In addition, the capital investment is more easily estimated than large-scale types.


  • Pelton type (horizontal axis)


  • Pelton type (vertical axis)



  • Screw type



  • Undershot type



Major Features and Advantages

① Three types of products are highly reliable equipment configurations and suitable for introduction and operation.

② The total generation efficiency is equal to or higher than conventional products.

③ The safety system can always work and automatically retract the turbine generator so as not to be damaged in

  abnormal conditions.

④ Onsite incidental work is minimal, and equipment costs are lower than conventional equipment by other companies.


Technology Data

Possible applications

Among the three types of generators, the Pelton type for high head generates power by the water pressure derived from height difference between the water intake and the turbine, and flow rate. It takes water from a high place in the river, supplies water to the Pelton turbine generator installed at a low position with a pressure pipe over a long distance.

In addition, the screw type and undershot type for low head are installed immediately to an existing weir (or additional head work might be required) with a width of 2 to 5 meter and a head of 1 to 3 meter, and utilize water falling from the weir to drive the water wheel to generate electricity.

The choice for low head between the screw type or the undershot type is determined by the locational conditions to be considered for installation and the effect on the water.

The following conditions are basic specifications.

・ Pelton type small hydropower generator has 30 meters head or more, flow rate of 5 L/sec or more

・ Screw type small hydropower generator has one meter head or more, flow rate of 200 L/sec or more

・ Undershot wheel type small hydropower generator has one meter head or more, flow rate of 800 L/sec or more


Competitive advantage

In general, in developing countries, there are many small and medium-sized irrigation canals in familiar places, so there are many places where such small and inexpensive generators are highly recommended to install.

The initial cost and operation cost at the site are relatively inexpensive compared to conventional products. The initial cost per kW is 1.7 million yen which is almost 70% of the initial cost of the conventional product.

The estimated initial and operation cost are as follows;

・ Water turbine generator 5 kW type set costs 8.5 million JPY

The cost of this turbine generator depends on the power generation capacity and condition of installation.

・ Operating cost is about 100,000yen/year for wear and tear parts for maintenance.

・ The wear and tear parts at the initial stage only will be delivered when the equipment is installed.



Table 1 Introduction of small hydropower generation



Features ——-Highly reliable configuration and generation efficiency

Our technologies include low head handling, cost savings, and a height adjustment mechanism for undershot hydropower generators.

Please refer to the attached brochures in detail.



Technical maturity / Past record of introduction

The company has so far installed 23 small hydropower units of the three types. In 2020, the company will install one unit of undershot type in Japan.

                                               Table 2 Installed generators of domestic and international




Information on patent related to this technology

Screw type

Patent No. 6020988

The company are currently applying for a patent on the undershot water type.


Contact person

Mr. Masayuki TSURUHA (Representative)

Email:[email protected]

Technology owners

Bamboo Chemical Laboratory, Ltd.