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Hydropower Potential Of Nepal
By DR. AB THAPA
Worldwide, hydropower represented 19 percent of the total energy generated in 1999, the most recent year for which data are available. In many countries, hydroelectric power is the dominant source of electric power. In 1999 Norway derived 99 percent of its power from hydroelectric plants Canada , the largest producer of hydroelectric power in the world, generated 340.3 billion KWh. in 1999. This figure constituted 60 percent of the nation’s electric power. Hydroelectric-power generation in the United States increased from about 16 billion KWh in 1920 to 305.6 billion KWh in 1999. Although the United States runs a close second to Canada in the total amount of hydroelectric power produced, only 8 percent of the electric power used in the United States was generated by hydroelectric power plants in 1999. Nepal produced only about 2.2 billion KWh hydroelectricity in the year 2003 despite the fact that Nepal is one of the very rich countries in hydropower resources. Its hydropower potential is estimated at 83.28 million KW.
INTERNATIONAL Water Power & DAM CONSTRUCTION journal had published some years back data on hydropower potential of various countries. The hydropower potential has been divided into three categories: (1) Gross theoretical hydropower potential, (2) Technically feasible hydropower capability and (3) Economically feasible hydropower capability. Hydropower potential or the gross theoretical hydropower potential has been defined as the annual energy potentially available in the country if all natural flows were turbined down to the water level of the border of the country with 100 percent efficiency. Such potential is expressed in terms of annual energy generation (GWh /year) or power (GW, MW or KW).
Determination of Nepal ’s Hydropower Potential
Dr. H.M. Shrestha had been conducting research works in the Moscow Power Institute of the former Soviet Union more than 40 years ago. His research works had culminated in establishing with a quite reasonable degree of accuracy the hydropower potential of Nepal to be about 83 million KW. As a result, his findings have been accepted without any reservation by everybody. In course of his daunting research works he had analyzed the maps of rainfall distribution and average surface run-off of the rivers flowing in Nepal . The typical profiles of Nepal ’s rivers were observed, and an empirical formula was derived that could be used for approximate evaluation of the power potentials of small rivers. The rivers were classified according to the sources of their feeding.
For the purpose of evaluation of the power potential, the rivers have been divided into two groups: (1) Big rivers with catchment area of more than 1,000 sq. km. (2) Small rivers, which have catchment area less than 1,000 sq. km. A total of 115 rivers were studied. Out of the total 115 rivers, the number of big rivers are 33. The rivers have been divided into basin wise also. The river basins are Sapta-Kosi, Sapta-Gandaki, Karnali& Mahakali, and southern rivers. Catchment areas of each of the above basins excluding the areas in Tibet are 27,300 sq. km., 31,600 sq. km., 47,300 sq. km., and 39,300 sq. km. respectably. Similarly the gross theoretical hydropower potential of each of the above mentioned basins are 23.35 million KW, 20.65 million KW, 36.18 KW, and 4.1 million KW respectively. According to Dr. Shrestha’s findings the gross theoretical hydropower potential of all big rivers with catchment area exceeding 1,000 sq. km. is 72.45 million KW. The hydropower potential of small rivers, which have catchment area less than 1.000 sq. km., is only about 10.83 million KW. Thus, Dr. Shrestha established that the theoretical hydropower potential of Nepal is 83.28 million KW.
Misleading Information
Our media, planners, politicians etc are never tired of telling that Nepal is the second richest country in the world after Brazil in hydropower resources. They chose to ignore even though they are repeatedly told that neither the Brazil is the world’s richest country in hydropower resources nor Nepal is the second richest. There are a number of countries even in our own neighbourhood such as China, India and Russia possessing far more hydropower resources by comparison with Nepal. China is the richest country in the world in hydropower resources. According to some recent data the hydropower potential of China is estimated to be about 676 million KW. Hydropower potential of Brazil is only about 365 million KW. Hydropower potentials of Russia , India , Peru , Colombia , Canada and Ecuador are 330 million KW, 300 million KW, 210 million KW, 147 million KW, 110 million KW and 93 million KW respectively. Technically feasible hydropower potential of Congo is 120 million KW. Thus the total hydropower potential of Congo should be far more than 110 million KW. Hydropower potential of Nepal is about 83 million KW.
There was a funny incident that explains how little we know about the hydropower resources in general and the techno-economic limitations in transmitting electricity across a very long distance in particular. Certain section of media and planners were upbeat when one of the multinational hydropower developers proposed a deceitful plan to develop Nepal’s abundant hydropower resources to export hydroelectricity to China, which is the world richest country in hydropower resources. Some of us might have been terribly shocked when that very multinational company was severely punished a few years later for its illegal deeds in its own home country. However, many of us might not have still realized that we were being deliberately misled.
Basin Studies
Basin studies had been carried out in the past to identify the economically feasible projects in Nepal . Status of each of the river basin studies is briefly described hereinafter: (1) Karnali River Basin Plan Study to utilize the hydropower potential had been done and the report submitted in 1966 by NIPPON KOEI of Japan under the UNDP assistance. This basin study was revised in 1990s to present in more detail the projects identified in the earlier studies. (2) Gandak River Basin Power Study was done by SNOWY MOUNTAINS E.C. of Australia in 1979. (3) Kosi Basin Masterplan Study was done under the assistance of the Japan International Cooperation Agency in 1980s.
Economically Feasible Hydropower Potential
Water and Energy Commission( WECS) of HMG had carried out in 1984 a study to determine the economic feasibility of major hydropower projects located across the country. With the exception of “megaprojects”, such as the Chisapani Karnali and High Kosi, or projects that had already been studied to feasibility level, such as the Sapta Gandaki, Mulghat, Kankai and Marshyangdi, virtually every project in the WECS projects list had been evaluated.
The above mentioned study suggests that due to the long lead time required for the development of hydropower projects, the planning studies to identify and evaluate potential future projects must be initiated 10 to 12 years in advance of the required in-service dates of the projects. The development of low cost sources of additional electric power supply in Nepal had often been hampered by a lack of up-to-date studies on alternative projects that could be considered for development. This resulted in the commitment to relatively costly projects for early development due to lack of alternatives. Unfortunately, Nepal is facing in 1980s, 1990s and even until now the same type of problems.
The WECS study points out that the high capital costs of most of the projects in the hydropower sector justifies fairly detailed and comprehensive studies at an early stage in order to ensure that an adequate number of feasible alternatives are available to allow selection of only the most economic projects for actual development. The study cautions that in the difficult geologic conditions found in the Himalayas it is always possible to encounter unforeseen problems that could significantly increase project costs.
(Dr. Thapa writes on water resources)
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