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PLACE:
BARAPOLE MINI HYDRO-ELECTRIC PROJECT , KANNUR
SUBMITTED BY
SREELAKSHMI A
1St
YEAR B.ED
PHYSICAL
SCIENCE
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Barapole Small
Hydro Electric Project
The project is
located in the Barapoal river which separates the Ayyankunnu Grama Panchayat of
Iritty Taluk in Kannur District and Makuttam in Kodak District in Karnataka.
The power house of the project was built at Palathinkadavil near Kootupuzha.
Figure shows a View of Barapole at Makuttam
The Barapole Hydro
Power Project is wholly owned by KSEB.
Barapole generates 15
MegaWatt of power with 5 MegaWatt of turbines on a small hydropower project.
The annual output is 36 Mega Units.
The cost of the
project is Rs 120 crore with a 15 MW installed capacity. The Barapole Hydro
Power Project is the largest among the mini hydro projects in Kerala. For the
first time in Kerala, the Barapal River, a tributary of the Valapattanam River,
is building a power project in the river. About one-third of the water that
flows into the river is discharged through two trenches built across the river
at the bottom of the river. The slopes to the left bank of the river above the
canals are two and a half meters wide and three meters deep on average. The
water flowing through the river through a sieve called track walk; sinks into the trench and the
water flows through the canal to a length of 15 m, 16 m wide and 74 m deep.
Shutters have also been built to control the flow of water to the lake. In
addition, the Solar Power Project is also envisaged to generate 15 MW of power.
The project is estimated to cost Rs 35 crore and the center will cost Rs 7.5
crore. Though it was originally conceived as a major project, a dam was
constructed across the river and the decision was changed by the Supreme Court
order that the water in the Rajiv Gandhi National Park should not be changed or
altered. According to the official, this project aims to provide maximum power during
the monsoon season and to conserve water in Iritty for summer.
Barapole
mini hydroelectric project
The
project can generate 36 million units of electricity per year. The project
includes the construction of conduits below the riverbed for diversion of water
to the power house. The other components include intake pool, power duct,
de-silting tank, the power channel and three penstock pipes and three turbines
with 5 MW capacity each. The project is located on the Barapole (Barapuzha)
river, a tributary of the Valapattanam river.
A
major advantage of the project is that its highest generation of power will be
during monsoon season. The power generated from the hydroelectric project will
be transmitted to the grid through the 110-kV substation at Iritty. The project
generates an additional 3 MW of solar power as solar panels are being laid over
the three-km long canal from the river. As the project is located on a site
ideal for developing eco-tourism, the hydel tourism wing of the KSEB is
planning to develop some amenities there to draw tourists.
HYDRO ELECTRICITY
Hydroelectricity is electricity produced from hydropower. In 2015, hydropower generated 16.6% of the world's
total electricity and 70% of all renewable electricity and was expected to increase by about 3.1% each year for
the next 25 years.
The cost of
hydroelectricity is relatively low, making it a competitive source of renewable
electricity. The hydro station consumes no water, unlike coal or gas plants. It
is also a flexible source of electricity, since the amount produced by the
station can be varied up or down very rapidly to adapt to changing energy
demands. Once a hydroelectric complex is constructed, the project produces no
direct waste, and it generally has a considerably lower output level of greenhouse gases than
photovoltaic power plants and certainly fossil fuel powered energy plants. Rainforests are the prime locations for the dams that
are usually required to create the force of water needed to generate electric power;
therefore cutting down the trees near a dam actually increased the amount of
water flowing into the dams.
PHYSICS BEHIND
HYDROELECTRIC POWER STATIONS
Hydroelectric and coal-fired power
plants produce electricity in a similar way. In both cases a power source is
used to turn a propeller-like piece called a turbine, which then turns a metal
shaft in an electric generator, which is the motor that produces electricity. A
coal-fired power plant uses steam to turn the turbine blades; whereas a
hydroelectric plant uses falling water to turn the turbine. The results are the
same.
Take a look at the following diagram of
a hydroelectric power plant to see the details
The theory is to build a dam on a large
river that has a large drop in elevation. The dam stores lots of water behind
it in the reservoir. Near the bottom of the dam wall there is the water intake.
Gravity causes it to fall through the penstock inside the dam. At the end of
the penstock there is a turbine propeller, which is turned by the moving water.
The shaft from the turbine goes up into the generator, which produces the
power. Power lines are connected to the generator that carries electricity to
our homes. The water continues past the propeller through the tailrace into the
river past the dam. By the way, it is not a good idea to be playing in the
water right below a dam when water is released!
Falling water produces hydroelectric power.
A hydraulic
turbine converts the energy of flowing water into mechanical energy. A hydroelectric
generator converts this mechanical energy into electricity. The operation of a
generator is based on the principles discovered by Faraday. He found that when
a magnet is moved past a conductor, it causes electricity to flow. In a large
generator, electromagnets are made by circulating direct current through loops
of wire wound around stacks of magnetic steel laminations. These are called
field poles, and are mounted on the perimeter of the rotor. The rotor is
attached to the turbine shaft, and rotates at a fixed speed. When the rotor
turns, it causes the field poles (the electromagnets) to move past the
conductors mounted in the stator. This, in turn, causes electricity to flow and
a voltage to develop at the generator output terminals.
Diagram of a hydroelectric turbine and generator.
Reusing water
for peak electricity demand
Demand for electricity is not
"flat" and constant. Demand goes up and down during the day, and
overnight there is less need for electricity in homes, businesses, and other
facilities. For example, here in Trivandrum, Kerala at 12:00 PM on a March hot
weekend day, there is a huge demand for electricity to run millions of air
conditioners! But, 12 hours later at 12:00AM not so much.
Hydroelectric plants are more efficient
at providing for peak power demands during short periods than are fossil-fuel
and nuclear power plants, and one way of doing that is by using "pumped
storage", which reuses the same water more than once.
Pumped storage is a method of keeping
water in reserve for peak period power demands by pumping water that has
already flowed through the turbines back up a storage pool above the power
plant at a time when customer demand for energy is low, such as during the
middle of the night. The water is then allowed to flow back through the
turbine-generators at times when demand is high and a heavy load is placed on
the system.
The reservoir acts much like a battery,
storing power in the form of water when demands are low and producing maximum
power during daily and seasonal peak periods. An advantage of pumped storage is
that hydroelectric generating units are able to start up quickly and make rapid
adjustments in output. They operate efficiently when used for one hour or
several hours. Because pumped storage reservoirs are relatively small,
construction costs are generally low compared with conventional hydropower
facilities.
Trench weir: An
innovative structure for diverting water from high gradient rivers
A weir is an impervious
barrier constructed across a river to raise the water level on the upstream
side.In a weir the water overflows the weir, but in
a dam the water overflows through a special place called a spillway.
Trench weirs are
commonly adopted in boulder streams for diverting water for use in hydropower,
irrigation and water supply schemes etc. Here, a trench is built across the
river below its bed level. The top level of this trench is covered with bars to
prevent the entry of sediment into the trench.
Conventional types of
raised-crest weirs for diverting water from the high gradient rivers for its
use in generation of hydropower, irrigation, water supply schemes, etc. are not
well suited as the afflux brings a remarkable change in morphology of the
river. The sediments are deposited upstream of the crest as a result, the intake
gets easily choked up. Moreover, any structural component that protrudes out of
the river-bed gets damaged easily by the force of large sediments rolling down
during floods. The most suitable weir adopted in such scenario is trench weir,
which is simply a trench built across the river below its bed level. The top of
the trench is covered with bottom rack bars. Water while flowing over it,
passes through the bottom racks and enters into the trench and being collected
in an intake well located at either of the banks at the end of the weir. This
type of weir has a definite advantage as it does not affect the morphology of
the river. However, due to being below the bed of the river, the bed sediment
load of size less than the clear spacing of the rack bars enters into the
trench which necessitates post-monsoon clearance of the trench.
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