Dissertation Assessment of Run-Of-River Hydropower Potential
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Dissertation Assessment of Run-Of-River Hydropower Potential and Power Supply Planning in Nepal using Hydro Resources ausgeführt zum Zwecke der Erlangung des akademischen Grades eines Doktors der technischen Wissenschaften unter der Leitung von Univ. Prof. Dr. - Ing. Christian Bauer E302 Institut für Energietechnik und Thermodynamik eingereicht an der Technischen Universität Wien Fakultät für Maschinenwesen und Betriebswissenschaften von Iswor Bajracharya, M.Sc. e1129962 1200 Wien, Brigittenauer Lände 6639 Wien, im April 2015 Abstract The basic premise for the development of water resources in the country is the availability of accurate and reliable information about the resources. Nepal is rich in water resources but, lacks the reliable information about the hydro potential. The first estimation of the theoretical hydro potential was done about 5 decades ago with limited data and analysis tools. Since then very few studies have been done in this field. Therefore, the first part of this study estimates the theoretical run-of-river hydropower potential of Nepal. A GIS- based spatial tool and SWAT (Soil and Water Assessment Tool) hydrological model have been used to estimate hydro potential. The estimated total theoretical run-of-river hydro potential of Nepal is 119,185 MW at 30% flow exceedance and 103,341 MW at annual mean flow. Although large numbers of hydropower plants are currently under-construction, it is unlikely that the growing electricity demand in the country can be met from these power plants at the current rate of development. Therefore, the second part of this study deals with the power generation and expansion planning of Nepal for the period 2015- 2030. The modeling tool, LEAP (Long-range Energy Alternative Planning), has been used for this purpose. The major problems associated with the development of transmission lines in Nepal are discussed. The critical issue to be addressed by the government and politicians to end the power crisis in the country is the development of transmission lines besides developing the new power plants. Therefore, the first priority has to be given towards the completion of under- construction transmission lines in the major power corridors where hydro projects are being developed and new hydro projects are being planned to build. This will not only connect the hydro projects currently under-construction in the national grid of the country, but also, attracts new investment in the hydro power sector which will help develop power capacity to meet the future electricity demand. The reduction of transmission and distribution losses plays a significant role in the supply side management. The required power plant capacity decreases significantly when the system loss is reduced. The study shows that electricity mix has to be used in the power supply planning to meet the future electricity demand. The current trend of run-of-river based hydropower development has to be changed and the priority has to be given in the development of storage type hydropower. Other renewable energy sources such as solar and wind, have to be used in the power generation. Furthermore, the result shows that the current rate of power capacity development will not be enough even to meet the base case electricity demand. The timely development of transmission lines, construction of new power plants with a suitable electricity mix and reduction of power losses in the system are the key points to meet the future electricity demand and end the power crisis in the country. ii Kurzfassung Die Grundvoraussetzung für die Erschließung von Wasserressourcen eines Landes ist die Verfügbarkeit von genauen und zuverlässigen Informationen über die Ressourcen. Nepal ist reich an Wasserressourcen, jedoch fehlt es an zuverlässigen Informationen über das Wasserkraftpotential. Die erste Schätzung des theoretischen Wasserkraftpotentials wurde vor ca. 5 Jahrzehnten mit begrenzten Daten und Analysehilfsmittel erstellt. Da seitdem nur sehr wenige Studien in diesem Bereich durchgeführt wurden, behandelt der erste Teil dieser Studie die Abschätzung des theoretischen Laufwasserkraftwerkpotentials in Nepal. Ein GIS-basiertes Raumgerät und ein hydrologisches Soil and Water Assessment Tool (SWAT) Modell wurden verwendet um das Wasserkraftpotential abzuschätzen. Einer Abschätzung zur Folge beträgt das totale theoretische Laufwasserkraftpotential in Nepal 119.185 MW bei 30% sicherem Zufluss und 103.341 MW bei Jahresmittelfluss. Obwohl derzeit einige Wasserkraftwerke gebaut werden, ist es unwahrscheinlich, dass der steigende Strombedarf im Land durch die Kraftwerksparkerweiterung abdeckt werden kann. Darum wird im zweiten Teil der Studie auf die Stromerzeugung und die Ausbauplanung in Nepal im Zeitraum von 2015 bis 2030 eingegangen. Hierfür wurde die Modellierungssoftware Long-range Energy Alternative Planning (LEAP) eingesetzt. In weiterer Folge wird das damit verbundene Problem des Ausbaus des Übertragungsnetzes erörtert. Der kritische Punkt der von der Regierung zeitnah angegangen werden muss um die Elektrizitätskrise im Land zu beenden, ist der Ausbau des Übertragungsnetzes neben der Entwicklung neuer Kraftwerke. Erste Priorität hat der rasche Ausbau des Übertragungsnetzes im Bereich der sich im Bau befindlichen Wasserkraftwerke und dort wo weitere Projekte geplant sind. Dadurch werden nicht nur die sich im Bau befindlichen Kraftwerke ans Netz angeschlossen, sondern ebenfalls neue Projekte attraktiver, was in weiterer Folge dazu beiträgt, die installierte Leistung zu erhöhen um den Strombedarf abdecken zu können. Im Versorgungsmanagement spielt die Reduktion der Übertragungs- und Verteilungsverluste eine bedeutende Rolle, da die erforderliche installierte Leistung signifikant reduziert werden kann, falls die Systemverluste abnehmen. Die Studie zeigt, dass ein Elektrizitätsmix im Versorgungssystem eingesetzt werden muss um den Bedarf abdecken zu können. Der aktuelle Trend hin zu Laufwasserkraftwerken muss zu Gunsten des Ausbaus von Speicherkraftwerken und anderen erneuerbaren Energieträger wie Wind und Photovoltaik geändert werden. Des Weiteren zeigen die Ergebnisse, dass die momentane Entwicklungsrate der installierten Leistung auch nicht ausreicht um den Basisfall-Strombedarf abzudecken. Der zeitgerechte Ausbau des Übertragungsnetzes, die Errichtung zusätzlicher Kraftwerke im Rahmen eines passenden Energiemix und die Reduktion der Systemverluste sind die Schlüsselstellen um den künftigen Elektrizitätsbedarf abdecken zu können und die Stromkrise zu beenden. iii Acknowledgement A journey is easier when travelling together. This dissertation is the result of three years of my work whereby I have been accompanied, supported, motivated and guided by many people. It gives me immense pleasure to express my gratitude and sincere thanks to all of them. First and foremost, I would like to express my sincere gratitude and regards to my advisors, Univ. Prof. Dr.-Ing. Christian Bauer and Ass. Prof. Dr. techn Eduard Doujak, for their continuous support, guidance and encouragement throughout my academic program without whose advice it would not have been possible to write this dissertation. Likewise, I would like to express my sincere gratitude to my second advisor, Ao. Univ. Prof. Dr. Bernhard Pelikan from BOKU University for his valuable suggestion and comments. Next, I would like to express my deep gratitude and thanks to Prof. Dr. Tri Ratna Bajracharya from Institute of Engineering, Nepal for his support throughout my study period. My special thanks go to my colleague Mr. Leopold Ruppert for his help for revising the German translated abstract of my thesis. I would like to thank all of my colleagues in Institute for Energy System and Thermodynamics, Vienna University of Technology for their kind co- operation and help during my stay in Vienna. Next, I would like to acknowledge Prof. Dr. Bhakta Bahadur Ale, Prof. Amrit Man Nakarmi, and Dr. Rajendra Shrestha from Institute of Engineering, Tribhuvan University for helping me in one way or another. Thanks go to Dr. Raghunath Jha from Department of Civil Engineering, Tribhuvan University for his valuable suggestion. I am indebted to my friend Mr. Nawraj Bhattarai for his love and care. I would like to thank Mr. Lekh Natha Bagale for his help of weather data from DHM, Nepal. Thanks go to Mr. Gyanendra Lal Pradhan, Executive Chairman of Hydro Solutions, Nepal for his valuable suggestions. I am also deeply grateful to Prof. Dr. Govinda Raj Pokharel, Mr. Ram Prasad Dhital and all other persons from various organizations in Nepal whom I met during my field visit and helped me directly or indirectly. I My special thanks go to OeAD, Appear Project for providing me financial support for my study in Vienna, Austria. I would like to thank Mrs. Elke Stinnig from OeAD for her kind co- operation and support throughout my study in Vienna. Last but not the least, I feel a deep sense of gratitude to my mother who taught me about life and always motivated me to progress in life. I am very much indebted to my sister Santa Kumari, my brother Rajkumar, my brother-in-law Niroj Joshi, my wife Sarita whose endless and unconditional love, care, patience and support allowed me to complete this study. Finally, I am grateful to all those who helped me directly or indirectly in my research. Iswor Bajracharya, Vienna April, 2015 iv Abbreviations ADB Asian Development Bank ASTER GDEM Advanced Space borne Thermal Emission and Reflection Radiometer Global Digital Elevation Model DEM Digital Elevation Model DHM Department of Hydrology