Hydro Based Technologies


Technology: Improved Water Mill (IWM)

Use: Mainly for grinding along with other end uses such as agro processing, electricity generation

An Improved Water Mill (IWM) is an intermediate technology based on the principle of existing mills that improves performance generating up to 3 kW. The improvement of traditional water mill is done by improving various components of the traditional mill but the most significant is replacement of traditional wooden runner with hydraulically better-shaped metallic runner having cup shaped blades.

Two types of IWMs are in practice, short shaft and long shaft. Short shaft(SS) are used solely for grinding purpose whereas the Long shaft (LS) are installed with grinding and other end uses such as paddy husking, saw-milling, lokta beating, chiuri expelling and many more including electrification. IWM provides energy services to households at a cheap investment and maintenance cost within a short period required for the construction work.  

Improved Water Mill specification

  • Head 20 meter
  • Discharge 20-100 l/s
  • Speed 200-250 r.p.m.
  • Output Power Capacity 3 kW

For whom: Ghatta owners and community
Subsidy: Government subsidy available under Improved Water Mill Programme in selected districts


IWM Electrification

Besides agro-processing, IWM electrification is a very important end-use that can be coupled with LS IWM system. Depending upon the water resources available the electricity up to 5 kW can be generated from the IWM electrification system. For this purpose an induction generator with controller device can be added to the LS IWM by means of pulley and belt transmission system. The electricity generated from IWM electrification system can be used for basic lighting purpose, mobile charging operation of TV and radio and small cottage enterprises etc. To promote IWM electrification system government provides subsidy upto 5 kW system only.

The short shaft IWM is limited for grain grinding only. To optimize the capacity of SS IWM, a new technology Axial Flux Permanent Magnet Alternator (AFPMA) has been developed from joint research of CRT/N, Gramin Urja Tatha Prabidhi Sewa Kendra and Kathmandu University. AFPMA can be easily coupled with SS IWM and electricity can be produced. The technology has been able to produce power upto 1 kW and it is under research for the system to generate power upto 3 kW.

Technology: Motor Dynamo-based Family Hydro (MDFH)

Use: electricity generation

MDFH is a technology based on generation of electricity via 12 Volt (V) motor dynamos. A pelton turbine is coupled with the dynamo which is run through water. In order to generate electricity the dynamo must be excited through external 12 V battery. This is a DC system and the power output ranges from 60-100 watts depending upon the head of the site (Head above 30 metres is preferred).

MDFH components:

  • 12 V motor dynamo
  • Pelton runner of 90 mm diameter made of brass designed for 1800 RPM
  • 12 V excitation battery
  • Nozzle 8-10 mm dia
  • Pentock 1-1.5 inch dia
  • Transmission wire 7/22 Standard Wire Guage (SWG)
  • House wiring wire 3/22 SWG

This technology can be used for any DC operating any devices such as lighting DC compact florescent lamp (CFL), Radio, charging mobile and external batteries. Devices requiring voltage less than 12 V, for example 6 V radio, can be operated by using a DC-DC converter which is readily available in the market.

For whom: household and community
Battery charging can be done as business
Subsidy: No provision of government subsidy, Subsidy provided by CRT/N


Technology: Hydraulic Ram Pump

Use: irrigation and drinking water
A hydraulic ram pump (hydram) is an automatic pumping device which utilizes a small fall of water to lift a fraction of the supply flow to a much greater height; i.e. it uses a larger flow of water falling through a small head to lift a small flow of water through a higher head. The main virtue of the hydram is that its only moving parts are two valves, and it is therefore mechanically very simple.

Hydram Specification:

  • Drive head range: 2 – 30 m                 
  • Drive flow: 10 – 2000 l /min
  • Drive pipe diameter: ¾” – 8”
  • Delivery head range: up to 100 – 200 m
  • Delivery flow: 0.5 – 200 litres/min (up to 300m3/day)
  • Ram pumps system efficiency: 50-75 %

For whom: community
Subsidy: No provision of government subsidy