MULTIPURPOSE MINI / MICRO
HYDRO PROJECT PLANNING AND
MANAGEMENT
PRJ 002
NYAKINDA WALTER
F17/10476/2003
SUPERVISOR: MR. WALKADE
EXAMINER: DR. MANG’OLI
INTRODUCTION
Category
Size
Pico-hydro
Micro -hydro
Mini-hydro
Small -hydro
Medium-hydro
Large- hydro
< 5kW
5 kW–100kW
100kW-1000kW
1MW – 15MW
15 MW- 100 MW
More than 100 MW
PROJECT OBJECTIVE
The objective of this project is to investigate the
feasibility of multipurpose mini/micro hydro
projects on a co-operative or self help basis
Mini/micro hydro projects can be divided into
three categories based on their specific
utilisation:
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Milling project
Add-on electrification projects
Stand-alone electrification
Benefits of MHP scheme
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They require considerably less funding and a shorter
time to implement
They permit the local population participation in all
activities
Since the site is usually next to the load centre,
transmission distances are short
Decentralised nature of these schemes coincide with
the dispersed nature of rural population
The interference with the environment is minimal
They do not require elaborate civil works and the
power generating equipment is relatively simple and
can be locally manufactured
Project Feasibility
A list of studies that should be undertaken:• Topography and geomorphology of the site.
• Evaluation of the water resource and its generating
potential
• Site selection and basic layout
• Hydraulic turbines and generators & their control
• Environmental impact assessment and mitigation
measures
• Economic evaluation of the project and financing
potential
• Institutional framework and administrative procedures
to attain the necessary consents
Components of a mini / micro hydro power scheme
Lateral Intake
Sediment Trap
Losses
Power produced can be calculated as follows:
P= ρ Q g H η
Where:
n ρ = specific water density [kg/m3]
n Q = Discharge [m3/s]
n H = "net head" [m]
n g = acceleration due to gravity [m/s2]
n H g = specific hydraulic energy of machine [J/kg]
n η = turbine efficiency
Turbine Selection based on Head and Discharge
Cross-flow turbine
Synchronous generators
The synchronous speed is given by:
Nsync = 120 f
P
Where: f = frequency
p = number of poles
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Asynchronous generators
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These are simple squirrel-cage induction motors
running at a speed directly related to system
frequency.
The generator is accelerated to a speed above
synchronous speed.
For stand-alone plants the generator must be supplied
with reactive power. This is achieved by adding a bank
of capacitors across the machine terminals.
Slip is given by:
S = Nsync – Nm
Nsync
Where: Nsync = synchronous speed
Nm = motor speed
Nm = 120 f (1 - s)
P
The generating speed (Ng) is given by:
Ng = 120 f (1 + s)
P
Typical efficiencies of small generators
Rated power [kW]
10
50
100
250
500
1000
Best efficiency
0.910
0.940
0.950
0.955
0.960
0.970
Community ownership
Programmes promoting the use of micro-hydro
power in developing countries have concentrated
on the social, as well as the technical and economic
aspects of this energy source.
Ø Technology transfer and capacity building
programmes have enabled local design and
manufacture to be adopted.
Ø Local management, ownership and community
participation has meant that many schemes are
under the control of local people who own, run
and maintain them.
Ø
CASE STUDY - TUNGU-KABIRI MHP PROJECT
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The site selected for the project case study was on
River Tungu about 200Km north of Nairobi, and
12Km from Chuka town, close to Mbuiru village.
About 200 members of this community came together
and formed a commercial enterprise to own, operate
and maintain the micro hydropower plant.
Each individual bought a share in the company, with
a maximum share value of about US$50.
The members also contributed labour, dedicating
every Tuesday for over a year to the construction
work
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The day-to-day operations of the plant are
managed by a 10-member community power
committee
The electricity is currently used mainly for microenterprises such as a welding unit, a batterycharging station, a beauty salon, a barber shop,
photographic studio, video hall and some retail
outlets.
The scheme now distributes electricity over an area
of 3 square kilometres.
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The canal length is 250m
The penstock length is 20m
Head height is 13.5m
The facility is rated at 18 kW; it produces 18kW
mechanical power or 14 kWe.
Flow rate in canal is 200 l/s with an effective 180 l/s
running a T12 cross-flow turbine.
The cross flow turbine is connected to a 40 kW
synchronous generator that produces 3-phase AC
power.
MHP in Kenya
CONCLUSION
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So far only a few mini hydro schemes have been
realised, either as part of the national grid supply or
as stand-alone systems for agro-industrial
establishments or missionary facilities.
Only few examples of community-based
installations are known.
FURTHER WORK
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It is expected that the recent liberalisation of the
Kenyan power market will facilitate the engagement
of private project developers and independent power
producers in areas presently not sufficiently served
by the national grid.
The Ministry and the Kenya Bureau of Standards is
preparing standards and code of practice to govern
the installation and operation of SHP, this steps are
expected to encourage the development of
community based mini/micro hydro power
initiatives
END
THANK YOU