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Small hydropower generating units can ease power crisis

MD. Asadullah Khan
Energy plays an important role in accelerating economic growth inasmuch as it serves as an important element in providing food, shelter, healthcare facilities, safe water, sanitation, education and access to jobs to either an individual or group or the whole community. Sustainable human development, which means economic growth through equitable distribution of benefits, can only be ensured through the fulfillment of the energy needs of the nation. This brings into focus the interrelation between per capita energy consumption and per capita GDP. emphasising the fact that improvement in human status contributes to increase in per capita energy consumption.
The development of the country's energy sector hinges mainly on power generation based on natural gas, which is the country's only indigenous source of fuel. Till January 1997, as newspaper reports indicated quoting Petrobangla sources, the net recoverable reserve of natural gas was 10.88 TCE With power demand shooting up to 5400 MW since early June, against a generation capacity of 4184 MW, and despite commissioning of a spur line in Jalalabad gas field, there has been no appreciable increase in power generation. .
It is, therefore, imperative that the government starts exploring possibilities of generating power by using alternative and environmentally benign sources of energy. Experts indicated in a workshop held at Buet in 1999 the vast potential of hydropower, especially small hydropower units, in and around Bangladesh, especially in Nepal.
Hydropower is the one renewable energy resource with which mankind has long been familiar, and for which most efficient energy transformation technology is available. Most strikingly, the conversion efficiency from natural resource to electricity is 85% to 90% for hydropower compared to 20% to 30% for fossil fuels, nuclear and geothermal sources. People worldwide are now keen to go for hydropower because its environmental impact, except for land submergence under reservoirs, is minimal. The continued growth in the demand for electricity throughout the developed world has raised concern about the ability of the environment to sustain this development without harm to itself.
This brings into focus the need for harnessing hydropower, especially minihydropower units that are very much cost effective, with the possibility of providing an attractive means of achieving rural electrification, power supply to irrigation,
drainage pumps, and cottage industries. Moreover, the plants and equipment used in hydropower generation are relatively simple. Nepal, India, Pakistan, Thailand, and the Philippines have made significant strides in hydropower development. Hydropower unit sizes up to 1000 KW are termed as mini whereas small units may range from 500-5000 KW.
Despite the fact that hydropower is a clean and cheap method of power production, the scope for hydropower generation is quite limited in Bangladesh because of the topography. The lone hydropower plant in Kaptai, Rangamati, with installed capacity of230 MW, continues to generate 180 MW without any major breakdown or overhaul since its commissioning in 1962.
The chief engineer of the Kaptai hydroelectric project told me in 2003 that the generating capacity of the Karnaphuli project could be raised to 300 MW by addition of at least two units. There is a feeling among many knowledgeable quarters that the discharge from the Karnaphuli Hydroelectric Power plant could be recycled to the Kaptai lake either by conventional water pumps or by installing pumped-storage type units to enhance the potential of the Kaptai lake and hence generate more power.
Experts indicated that there are certain locations within the country where small hydropower stations could be set up as per the recommendations of the IECO Master Plan inl964 and the subsequent study made by four working groups in 1981. The working group explored the possibility of setting up mini-hydropower generation stations on hilly streams, chars, and rivers having steep slopes.
The recommended sites where projects could be started on a priority basis are: Fey’s Lake at Pahartali, and Choto Kumira in
Chittagong proper, Sealock in Bandarban, Nikhari Chara and Madhab char in Baralekha, Moulavibazar, Ranga Poni Gung in Jaintiapur of Sylhet, Bhugai Kangsha in PS Nalitabari and Marisi in PS Jhinaigati in the district of Sherpur, Punarbhaba and Talma in greater Thakurgaon and Pathraj in Dinajpur. Studies of these sites suggested that a total annual production of 11,56,320 KWH in Chittagong-Bandarban area, 63,06,041 KWH, in Mymensingh-Sherpur district, and 18,70752 KWH in the greater Dinajpur-Rangpur area could be generated.
Sangu river: Studies also suggest that by damming the river Sangu at Tarasa Chara location and building a reservoir with a surface area of 32,500 acres and a capacity of 1900,000 acre-ft, power generation of about 82 MW at this site could well-nigh become possible.
Matamuhuri river: A compacted earthfilling dam could be constructed at Champatoli over the Matamuhuri river with an installed capacity of 17,500kW.
Teesta barrage project: The Teesta barrage project built in 1990 with regulating structure holds promise of generating 125 million kWh of electrical power. There are at least 19 potential sites of hydropower generation in the Teesta barrage maintaining head difference of evenl metre because of enormous discharge available here. At least for six months in a year around the monsoon season, power can be generated in these sites. Other than the sites described above there are many streams in the hill districts of Rangamati, Khagrachari and Bandarban where small storage can be created for hydropower generation.
In the context of development of hydropower in the whole region, including India, Bangladesh and Nepal, Engr. Rishi Shah, an expert from Nepal, indicated in his paper at a workshop at Buet in
1999 that the Himalayan Kingdom of Nepal possesses hydro power potential of an unimaginable magnitude.
Energy, both electrical and mechanical, can be harnessed from the mighty rivers flowing down the steep gradient of the mountains for the development^ not only of Nepal but also for the entire region. They possess hydroelectric power potential of about 83 GW (1GW= Ibillion watt) out of which only 50% is considered to be economically feasible for exploitation.
In Nepal, some encouraging work has been done for promotion of micro/mini hydropower capacity up to 100 kW/5 MW by the private sector to provide electrical energy to many communities living in remote areas that are not connected with the national electrical grid/network. BBC circulated a news bulletin on July 28 that indicated that Nepal was building a hydroelectric plant that will produce 42,000 MW, a power potential that could be shared by the countries in the region provided India agrees to extend the grid line over its territory. There have always been excellent ideas on the establishment of a regional power transmission network within the Saarc countries but, shockingly, those ideas never came to fruition, frustrating the very spirit and the objective of Saarc.
There are instances galore of such large-scale power sharing in the countries of Latin America. The Itaipu Dam between Paraguay and Brazil is the largest hydropower project (14,000 MW) so far known. The two countries saw the potential of joint development because Paraguay could not use half of the power from the project.
Brazil purchases the power Paraguay does not need. Interestingly, there are strong electric ties between various
European countries with long-term purchase agreements. In Central Asia, there are power purchase agreements between Kyrgystan, China and Pakistan. Kyrgystan has been selling hydropower to China for sometime now.
Encouragingly, some of the historical and political barriers among these couri-tries have been pulled down in favour of economic development. Reports have it that a 500 KV transmission line has been built through Malaysia to link Thailand and Singapore. Thailand also buys electricity from Laos.
In the case of Bangladesh and its contiguous region, there appears to be as much concern as there are opportunities. While there are opportunities for importing electricity from Nepal into northern part of Bangladesh, there are disconcerting questions of sovereignty, politics and above all, concern about long term reliability. By all reasoning it can be said that, if the water sharing agreement signed between Bangladesh and India is any indication, one can be hopeful that similar agreement can be reached in the power sector as well.
Nepal will sell electricity to Bangladesh and India will transfer power for a fee. A series of agreements on inter-dependence can be reached to reduce the threat of supply interruptions even in times of political conflicts in the region. While the whole world is reeling under the looming threat of increasing greenhouse gas emissions and global warming caused by burning of fossil fuels in the power plants, exploitation of hydropower seems to be a brilliant idea to be exploited.
Md Asadullah Khan is a former teacher of physics and Controller of Examinations. BUET. E-mail aukhanbd@gmail com