Abstract :
The ever
increasing demand of the electric power with the increase in population has put
all the pressures. To tap each and every source of power generation the conventional
method of power generation need to be reinforced with different alternatives.
Micro hydro
power was once the world's prominent source of mechanical power for
manufacturing. Micro hydro is making a come back for electricity generation in
homes. There is also growing market for
micro hydro electricity in developing countries. Hydro power is the conversion
of the kinetic energy in falling water into electricity. The vast majority of
hydro power today is being generated at huge facilities with large dams and
reservoirs. Reliable, low-cost, emission-free, renewable energy is produced in
this way, but the environmental and social costs of large scale hydro projects,
from the damming of rivers and flooding of large tracts of land to the
displacement of people from the affected areas has led to increasing opposition
to further large scale hydro power development.
Micro-hydro
is hydro power generation on a small, even tiny, scale. Recent improvements in
small turbine design allow for the efficient generation of power from even a
low-volume stream with only a short vertical drop (known as "head").
Scheme
components:
Figure 1
shows the main components of a run-of-the-river micro-hydro scheme. This type
of scheme requires no water storage but instead diverts some of the water from
the river which is channeled along the side of a valley before being ‘dropped’
into the turbine via a penstock. In figure 1, the turbine drives a generator
that provides electricity for a workshop. The transmission line can extended to
a local village to supply domestic power for lighting and other uses.
There are
various other configurations which can be used depending on the topographical
and hydrological conditions, but all adopt the same principle.
Small run-
of-the-river hydropower system consists of these basic components:
Water
conveyance – channel, pipeline, or pressurized pipeline (penstock) that
delivers the water
Turbine or waterwheel- transforms the energy
of flowing water into rotational energy.
Alternator
or generator – transforms the rotational energy into electricity
Regulator-
control the generator
Wiring –
delivers the electricity
Some system
also use batteries to store electricity generated by the system, although
because hydro resources tend to be more seasonal in nature than wind or solar
resources, batteries may not always be practical for hydropower system. If
batteries are used, they should be located as close to the turbine as possible,
because it is difficult to transmit low voltage power to long distance.
Suitable
conditions for micro-hydro power
The best
geographical areas for exploiting micro-scale hydro power are those where there
are steep rivers flowing all year round, for example, the hill areas of
countries with high year-round rainfall, or the great mountain ranges and their
foothills, like Himalayas. Islands with moist marine climates, such as the
Caribbean Islands, the Philippines and Indonesia are also suitable. Low-head
Turbines have been developed for small-scale exploitation of rivers where there
is a small head but sufficient flow to provide adequate power.
To assess
the suitability of a potential site, the hydrology of the site needs to be
known and a site survey carried out, to determine actual flow and head data.
Hydrological information can be obtained from the meteorology or irrigation
department usually run by the national government. This data gives a good
overall picture of annual rain patterns and likely fluctuations in
precipitation and, therefore, flow patterns. The site survey gives more detailed
information of the fluctuation in river flow over the various seasons.
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