Energy is one of the most fundamental elements of our universe. Human
being use energy to do work, lights our cities, powers our vehicles, trains,
planes and rockets, warms our homes, cooks our food, plays our music and
gives us pictures on television. Energy is the basic inevitability for
survival. It is indispensable for development activities, to promote education,
health care, transportation and infrastructure for attaining a reasonable
standard of living and is also a critical factor for economic development
and employment. Bangladesh has very limited nonrenewable energy resources
of its own. She is facing energy predicament and serious desertification
problem in rural areas including suburban and coastal region, especially
in the hilly areas. These issues could be enhanced if renewable energy
is used as a primary source of energy in those areas. Micro-hydroelectric
power generation may be a potential energy source for hilly areas in Bangladesh.
In hills, there are springs and streams that are running throughout the
Now a days, energy crisis especially electricity in the form of electrical
energy has been raised to a higher degree throughout the country. Lack
of proper maintenance of the machines and equipments, many years old setup
in production of electricity have made the situation even more badly.
The demand for electricity is increasing day by day for burgeoning population
as well as industries.
Energy crisis has been emerging out since a few years. Due to lack of
far extending plan to cope the demand of energy, the government has failed
to solve the problem and the situation is getting worse day by day. In
recent days, the electrical energy crisis become in such extent that even
four to five hours we are under load-shedding. The people of town and
villages are suffering from scorching heat and they are blaming the government
and the local electrical power authority. Under such a crucial energy
situation, we should look for alternative sources for generating powers.
Khagrachari Hill District is full of hills and waterfalls. The people
of hilly areas usually live on the top of the hills. The major problem
for them is the crisis of drinking water on such height. A small scale
hydroelectric power station can be set up across these springs and streams.
The hydroelectric energy thus obtained can be used to drive pumps for
lifting water on the top of the hills, thus solving water problem for
highlanders. The people in the hill areas are still deprived and don`t
have the civil facilities such as sanitation, proper education and economy.
The main objectives of this research are to study and locate proper location
for micro-hydroelectric power generator, to measure the available height
and flow rate and finally to estimate the plausible power generation.
The effects on the environment have also been addressed to a limited extent.
MICRO-HYDROELECTRIC POWER GENERATION
Micro-hydroelectric plants are the smallest type of hydroelectric energy
systems. They generate between one kilowatt and one megawatt of power.
The amount of electricity that can be generated at a hydro plant is determined
by two factors: head and flow. Head is how far the water drops. It is
the distance from the highest level of the dammed water to the point where
it goes through the power-producing turbine. Flow is how much water moves
through the system. Generally, a high-head plant needs less water flow
than a low-head plant to produce the same amount of electricity.
A dam serves two purposes at a hydro plant. First, a dam increases the
head or height of a waterfall. Second, it controls the flow of water.
Dams release water when it is needed for electricity production (Special
gates called spillway gates release excess water from the reservoir during
HYDRO ENERGY SCENARIO IN BANGLADESH
Renewable energy exploitation in Bangladesh is not new. People are using renewable
energy sources like solar, wind, hydro power for different purposes from primordial
time. The scope of hydropower generation is very limited in Bangladesh as the
country consists of low and flat lands except some hilly regions in the north
and northeastern part. The only hydro power station of the country, the Karnafuly
Hydro Power Station with a generating capacity of 230 MW by 7 units, is located
in Kaptai, across the river Karnafuly (Sadrul Islam et
al., 2006). This plant is generating 3.28% of total 3651.2 MW demand
of the country (Islam et al., 2008). The first
micro hydropower unit of 10kW has been installed in a village of Bandarban through
private initiatives. The project is providing electricity to 140 families in
the village and to a Buddhist Temple (Islam et al.,
Sangu project would be a new project with estimated annual energy of
about 300 GW h year-1. For an installed capacity of 140 MW,
the annual plant factor is 23% and it is assumed that the plant would
operate in a peaking mode. Matamuhari hydroelectric project would be a
potential project of capacity 75 MW and approximate average annual energy
200 GW h year-1. It would operate in a peaking mode similar
to the Sangu project.
Barkal is one of the remote and unelectrified Upazila (sub-district) in the
Chittagong Hill Tracts region (ranging 300-500 m in height). Engineers of Bangladesh
Power Development Board (BPDB) have conducted reconnaissance survey in the Upazila
and identified availability of water sources for Micro-Hydro Power Plant. Based
on the electrical load demand of the adjacent area, they proposed and designed
a 20 kW Micro-Hydro Power Plant with the help of RETScreen, developed by CANMET
Energy Diversification Research Laboratory of Canada (CEDRL) (Sadrul
Islam et al., 2006).
In 1981 the Water Development Board and Power Development Board carried out
a study on the assessment of Small/Mini Hydropower Potential in the country.
It identified 12 potential rivers/charas with an estimated annual production
of 1.1 GW h in Chittagong-Bandarban area, 6.3 GW h in Sylhet and Moulovi Bazar
area, 8.6 MW h in Mymensingh-Sherpur area and 1.8 GW h in the Dinajpur-Rangpur
area. However, only inadequate study has been made for the micro-hydro potential.
Recently, LGED (Reba, 1999) has taken up a project at
Bamer chara in Bashkhali of Chittagong District and BCSIR (Hasanuzzaman
et al., 2002) in Sailpropat, Bandarban and in Madhobkundu, Moulovibazar.
The BCSIR has estimated that these two sites have the potential for annual energy
production of 43.8 MW h and 1.3 GW h, respectively.
In 1984, six Chinese experts visited Bangladesh and identified some potential
sites for development of mini hydro power plant. Out of these sites, only
Mahamaya Chara has been taken up for development of an integrated project
for flood control, irrigation and power generation. A working group has
been formed by the engineers of Bangladesh Power Development Board (BPDB)
and Bangladesh Water Development Board (BWDB) to carry out groundwork
of the project. A dam is proposed to be constructed on the Mahamaya Chara
for the retention of monsoon run-off from a drainage area of about 10.5
km2 and to provide irrigation facilities from the reservoir
behind the dam. It is also planned to utilize the reservoir water for
the generation of hydroelectricity. A mini hydro power plant will be installed
at the foot of the dam.
Some researchers have studied a channel in Halda River near Madhunaghat Bridge
on the Chittagong-Kaptai road in the Chittagong district as prospective site
for micro-hydro (Wazed et al., 2004). The average
flow velocity is 0.75 m sec-1, average flow rate is 7.87 cu-m sec-1
and average available water head is 3.28 m. The monthly average flow rate and
available head in Mohamaya Chara Bamerchara and flow rate in Sailopropat, Bandarban
(Reba, 1999) has been reported.
SAPCHARI WATERFALL IN KHAGRACHRI DISTRICT
Khagrachari is a hilly district situated east-southern region of Bangladesh.
There are a few waterfalls, springs and streams throughout this hilly
area. But not all of them are suitable to set up a micro-hydro power station.
Considering water flow, locality oriented, approachability and security
we have chosen the Sapcharai waterfall for study. The abridged portrayal
of the site is shown in Table 1.
Sapchari waterfall is situated in Khagrachari Hill District and about 115 km
north from Chittagong town. The waterfall is near to the Sapchari village and
is emerged out from Alutila Hill Range situated by the Chengi River. One may
go Khagrachari by bus from Chittagong city. From Khagrachari bus terminal using
rickshaw or some other means s/he may reach at Khabangpujjya. Then across the
Chengi river the Sapchari Village is situated. In the south of the Sapchari
village the Sapchari waterfall is located. The landscape is very charismatic
and the whole view of Khagrachari town can be observed from the top of the waterfall.
However care should be taken for snakes that might be poisonous. While going
up on the hills it will be very wise to take a first aid box for any incident.
Figure 1 and 2 show the photographs of the
Sapchari water fall, its stream, reservoir and flow from the reservoir.
|| Summery description of Sapchari waterfall site
|| Photograph of the Sapchari waterfall (A) and the Sapchari
stream originated from the waterfall (B)
||Photograph of the top reservoir of the waterfall (A)
and water flows from reservoir to the waterfall (B)
DATA COLLECTION AND ANALYSIS
Data collection is a major task in this study. The data was collected
throughout the year 2007 and during January-August, 2008 which covers
the extreme dry season to full monsoon of Bangladesh. The place is located
at the Hill tracks in Khagrachari district of Bangladesh. The Sapchari
waterfall has a primary reservoir and a secondary reservoir from which
the main waterfall is getting down to the third reservoir. The head from
the primary to secondary reservoir is 3.6 m (11.81 ft) and from the secondary
(Main Waterfall) to tertiary reservoir is 10 m (32.81 ft). The flow rate
is measured simply with a bucket and a stopwatch. We have measured flow
rate in the year 2007 and during January-August, 2008 that cover the shoddier
dry Summer to precarious rainy season of Bangladesh.
|| Time of day vs flow rate of water in cu-m sec-1
||Average flow rate of water in cu-m sec-1
in the months
||Average power generation in watt (W) in the months
Figure 3 and 4 show, respectively
the flow rate and average flow rate of the water in the waterfall in the
observed period. The water flow in a day is nearly steady. The variation
in the value may be of error in measuring the flow rate. It is pellucid
that the flow rate is as low as 0.0035 cu m sec-1 in Summer
and is as high as 0.038 cu m sec-1 in the rainy season. The
water flow is increases from summer and reaches the pick in the rainy
season. Then it starts to decline again.
The power generation capability with respect to the flow of the water
is exposed in Fig. 5. It is nearly proportional to the
flow rate. It is shown that the maximal rated power generation is about
RESULTS AND DISCUSSION
An extensive study has been carried out on the feasibility of hydroelectric
power generation in Sapchari Waterfall. A number of data has been gathered,
analyzed and sorted for decisions. There may remain some data fissure,
but enough data have been collected and analyzed to reach the final results.
||Head of the waterfall: 32.81 feet or 10 m
||Minimum flow rate in dry season: 0.0035 cu m sec-1
||Maximum flow rate in rainy season: 0.038 cu m sec-1
||Minimum power rating: 525 W
||Maximum power rating: 3458.11 W
||Transportation facility to the site: Medium
||Population in the vicinity: low, about 300 within 1 km2
Effects on ecosystem: There is a natural ecosystem in the surroundings
of the waterfall. Usually the water world in the waterfall consists of
small fishes, prawns and other microorganisms. Their natural surroundings
may be hampered by the oil and grease leakage from the mechanical moving
parts of the plant. Also, the people in the vicinity are used to live
on the water of the stream originated from this waterfall. The water pollution
by the oil and other lubricant leakage might be a great threat for population
health in the vicinity. If proper measure can be assured then these negative
effects will be very less.
Effects on local people`s life: The people in the area near the
waterfall are very underprivileged and live on cultivating the hilly areas
(Locally called Jum). With minimum electricity they can manage their daily
life more effectively and comfortably. They can enjoy all the facilities
of a city life. Also the maintenance of the plant needs a few people where
they might get employed. Using pumps they can manage their water easily.
If a micro hydro power plant is setup there, it will change their way
Effects on ecotourism: Tourism is not yet established in the area.
But it has an intense possibility to burgeon as a beloved tourist spot.
Though the spot of the waterfall has become an attraction for the adventurers,
it can be an additional feature for tourist attraction if a micro hydro
electric power plant is installed. The living standard of the local people
can be improved if the tourism is blossomed in this area.
Based upon the results and discussion, we could conclude that:
||The Sapchari waterfall is a prospective site for micro hydro power
generation. With the available head and flow rate a Kaplan Turbine
or a waterwheel will be the best for the electricity production and
the generator should be flexible enough to cover the range 500-3500
||Effect on the ecosystem of the area is very less and the ecotourism
will increases hopefully. Both the way of living and the living standard
of this vicinity will be ameliorated after such installation