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- On February 20, 2018
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Feb 18,2018 -The Government of Nepal has a new federal government after promulgation of new constitution and new government also set a target to end the crisis in Nepal in period of their governance . More over state chief minister of state no 6 , Mr Mahendra Bahadur Shai and Parliament member Mr Gajendra Bahadur Mahat just declared to electrify every region of the state. With the recent change of government, the fate of the plan is in limbo. Hydropower, the major source of Nepal’s electricity, cannot end Nepal’s energy crisis in such a short time because of its capital-intensive and time-consuming nature. Alternative technologies like solar, micro-hydro, biogas and wind have been explored; yet, for several reasons they have not been enough. More appropriate energy generation technologies have to be explored to widen energy access to different parts of Nepal.
A relatively new technology invented and commercialized in Europe and improvised now by researchers in Nepal shows promise of delivering small amounts of electric power—from a kilowatts up to few Megawatts. These technologies are commonly known as Low Head Hydro Power technologies. Compared to most hydropower plants of Nepal that need hundreds of meters of head (the difference of height between the points from where water is first released from a river or dam to the location of the turbine), and micro-hydro power plants that need tens of meters of head, Low Head Hydro Power can operate in less than a meter to 15 m of head.
Figure : Screw Turbine
Researchers of Nepal are working mostly on two types of low head turbine systems i.e Arcemedian Spiral Turbine commonly known as Screw Turbine and Gravitational Water Vortex Power Plant (GWVPP). The former one is one of the oldest hydraulic concepts. A Screw Turbine has an inner cylindrical shaft around which one or more helical surfaces (flights) are wrapped. A generator is placed at the top of the screw turbine shaft which results in electrical production when the hydrostatic pressures of water within the screw exert forces tangential to the helical surface, causing the screw to turn and water to flow from the top to the bottom of the screw.
Figure : Gravitational Water Vortex Power Plant
When water passes through a strategically designed basin, a vortex of water is formed causing the turbine located at the center of the basin to rotate. The energy of the turbine can either be used mechanically or be used to generate electricity. Compared to most hydropower plants of Nepal that need hundreds of meters of head (the difference of height between the points from where water is first released from a river or dam to the location of the turbine), and micro-hydro power plants that need tens of metres of head, GWVPP can operate in less than a meter of head.
Nepali researchers started research work in Low head Turbine in Nepal since 2012. After continuous efforts of several Nepali researchers, three major innovations were accomplished in GWVPP. Conical basins were found to be more efficient than the original design with cylindrical basins in forming water vortices. Similarly, if the turbine is positioned at 60 to 70 percent of height from the bottom, efficiency would be optimum. Moreover the curved balde profile runner with suitable blade angle (angle between blade and hub) is most efficient runner for power production. These innovations were a result of rigorous mathematical modeling, laboratory tests and design efforts. The researchers overcame problems typically faced by researchers in developing countries including lack of adequate funding and technical expertise, difficulty in manufacturing, and little support from governmental and non-governmental bodies. The results obtained have been peer-reviewed and accepted by the scientific community in international conferences and academic journals, including Elsevier’s Renewable and Sustainable Energy Reviews and Springer’s Journal of Environmental and Pollution Research.
With relatively lower installation costs and low head requirement, these plants can be installed in many places in Karnali region of Nepal, including the Tarai, thus providing a novel method for generating electricity in places without access to the national electricity grid. Recently a team of Engineers from Vortex Energy Solution have done pre-feasibility study on many river of Jumla and Kalikot i.e Gidi Khola, Tila Khola, Rudu Khola, Banchu Khola etc. Small power plants like these can be beneficial to small and medium enterprises in using local and renewable energy resources, thus greatly reducing their operating costs and carbon footprint.
Low-head small scale hydro-electricity generation is feasible in many places of Nepal, including the Tarai, and has the potential to help abate the energy poverty Nepal is facing. Innovations in Nepal’s universities should find their way to society and the international scientific community. Research and innovations like this should be supported by the government, media and the general public to encourage Nepali innovators to develop appropriate solutions to Nepal’s pressing problems.
Author: – Er. Rabin Dhakal, Researcher of Institute of Engineering
CEO- Vortex Energy Solution Pvt. Ltd.
Reference : http://urjanews.com/details/4609/Prospects-of-Low-Head-Hydro-Power-System-in-Karnali-Region-of-Nepal