M I N I   H Y D R O   P O W E R

The Dewata Minihydro

Technical Features

The project is based on a feasibility study which was done in early 2000 by ENTEC AG, a Swiss engineering consultancy firm specializing in Minihydro  implementation.
 

The following general layout was proposed in the study:

The flow of the Cikahuripan river is diverted with a Tyrolean weir into the settling basin and from there conveyed through the headrace canal along the left side of the road leading to the Dewata Estate,

  • at the end of the headrace canal there is a small storage facility with the function of a forebay,
     
  • the penstock connects the forebay with the two crossflow turbines in the powerhouse, which is located next to the joining of the Cikahuripan and Cimeri river,
     
  • the hydropower scheme is run in synchronization with the diesel generators, whenever the demand exceeds the possible supply from the hydropower scheme.

* Click to enlarge

 

The “design flow” of the Cikahuripan river is 600 l/s and it is available during 157 days (43%) of an average year. The minimum storage inflow of 260 l/s is available during 282 days (77%). This means, that with the planned storage size of 2.275 m2 and the current tea production practices it is possible to cover the full electrical load with the hydropower scheme alone during at least 60% of an average year. If during critical periods in the dry season, only green and Japanese tea, but no black tea is produced, it is possible to reach full hydropower coverage during 77% of an average year.



During the remaining time of the year the hydropower scheme is operated alternately with the diesel generators. The length of the periods during which it is possible to cover the full load with hydropower then depends on the flow available and the actual load.

Design of the hybrid hydropower/diesel system



Set-up

 

  • Full-scale exploitation of hydropower potential of Cikahuripan  River
     

  • Run-of-the-river scheme
     

  • Hybrid System with

    • Primary power supply from the hydropower scheme and
       

    • Intermittent supply from diesel generators and hydropower scheme during periods the river flow is not sufficient. 



Design Characteristics

  • Design flow:                              600 l/s (Cikahuripan)

  • Gross head:                                65 m (full storage)

  • Net head:                                    62 m (full storage)

  • Design capacity:                       240 kW (2x120 kW)

  • Storage size:                             2.275 m3    



Energy Output Hydropower Plant

  • Average output:                         106 kW

  • Annual output:                    925.000 kWh

  • Percentage of demand:                93 %   



Energy Output Diesel Generator

 

  • Annual output:                       72.000 kWh

  • Percentage of demand:                  7 %      


Penstock


Spiral welded, 6 mm wall thickness, 600 mm diameter,       200 m length
 


Turbines


Two 120 kW crossflow turbines T14 model                      
 (P.T. Heksa Prakarsa Teknik, Bandung)
 


Coupling

Fly-wheel


Direct coupling

one, 600 kg
 


Generators


two 165 kVA generators
(Hitzinger, Austria)
 


Controller


Digital control system DTC 14, remote control from factory power house
 

Civil works were executed by a local contractor using workmen from the tea estate and neighboring villages. Building materials for stone masonry were obtained from the nearby local area.
 

P.T. Hadie Dayanaputra,
Bandung
The contractor in charge of excavation, civil works, etc.

ENTEC AG
The Swiss engineering consultants assisting in  design and construction

P.T. Heksa Prakarsa Teknik, Bandung
The manufacturer of the turbine and steel structures


With the exception of imported generators and control electronics, all other equipment of the plant has been produced locally e.g. the turbines and steel structures by PT. Heksa in Bandung. The “local content” in the costs was more than 80%, which made it possible for the tea estate PT. Chakra to finance the investment from the internal revenue.

 


Click to Enlarge