Micro-hydro power is a type of Hydro
electric power that typically produced up to 100
kW of electricity using the natural flow of water.
These type of power plant can provide power to
an isolated home or a small community. Micro-
hydro system complement solar energy because
in many areas in winter the water flow is
maximum and solar energy is minimum. In such
areas micro-hydro power is used along with
photo voltaic solar energy.
Construction of a Micro-hydro power plant is
site specific. It is made up of a number of
components. Some of them are……
Turbines converts the flow and pressure
energy into mechanical energy. Turbines are
basically of two types i.e. Reaction & Impulse and
Depending upon the head of the available water
further divide in three categories i.e. High,
Medium & Low head.
According to site specification (i.e. head and
flow) we choose the turbine to use in micro-
hydro power plant.
Turbine type Flow Head
Pelton wheel Low High ( > 70 feet)
Cross Flow High Low (<25 feet)
P = 9.81 × ρ × Q × H
ρ = Density of water, kg/m3
Q = Flow Rate, m3
H = Head, meters
The standard generators used in
micro hydro power projects are
the synchronous generator and
the induction motor used as a
Induction generator :- Induction
generator usually an induction
motor. Which rotates 1-5% faster
then synchronous speed so that it
can achieve negative slip, to run in
Synchronous generator :- Salient pole
Synchronous generator or alternator are used in
micro-hydro projects. These generator supplies
its own excitation through rectifier or external
batteries system can be used for excitation.
Some times industrial pumps (i.e.
centrifugal) are use as generator.
Water turbines vary
in speed as load is
applied. This speed
variation will seriously
affect both frequency and
voltage output from a
To over come this
problem electronic load
controller is used in
micro-hydro power plant.
The ELC prevents speed variations by
continuously adding or subtracting an artificial
load, so that the generator is working permanently
under full load.
A further benefit is that the ELC has no
moving parts, it is very reliable and maintenance
Economic energy source.
No reservoir required.
Utilize natural flow of water.
No harmful effect on surrounding.
No costly equipment used.
Low power generation during summer
Suitable site characteristics required.
Efficiency is low .
New computerized control systems and
improved turbines may allow more electricity to
be generated from existing facilities in the future.
Small scale and low head hydro capacity will
probably increase in the future. Low head
turbines, and standardized turbine production,
lowers the costs of hydro-electric power at sites
with low heads.
Micro-hydro power plant is an important part of
world’s electricity supply. Specially in remote areas it
is providing reliable and economic source of
As no fossil fuel required in hydro power plant, it
can help to save other source of energy.