ENERGY STORAGE SYSTEMS FOR OPTIMUM ENERGY UTILIZATION OF VILLAGE HYDRO SCHEMES IN SRI LANKA By J.M. Athula LIBRARY UNIVERSITY OF MORATUWA, SRI LANKA MORATUWA This thesis was submitted to the Department of Mechanical Engineering of the University of Moratuwa in partial fulfillment of the requirements for the Degree of Master of Engineering in Energy Technology Department of Mechanical Engineering Faculty of Engineering University of Moratuwa Sri Lanka June 2007 University of Mora tuwa 89425 89425 D E C L A R A T I O N / hereby declare that this submission is my own work and that, to the best of my knowledge and behalf, it contains no material previously published or written by another person nor material which to substantial extent, has been accepted for the award of any other academic qualification of a university or other institute of higher learning except where acknowledgment is made in the text. J . M . A t h u l a 1 A B S T R A C T Compared to the other countries in the region, Sri Lanka has a deep penetration of approximately 75% of grid electricity. However, providing electricity every rural household is a difficult goal, without employing off-grid technologies. Accordingly, the present 2% of household are receiving off-grid electricity will become 6% by year 2010, according to the prevalent government policy. This requires new technological interventions in the micro hydro sector, as the quality of hydro resources available for exploitation is coming down rapidly. This study aims at developing a concept of optimum energy storage to explore such meagre hydro resources. The proposed concept takes the advantage of highly developed technologies such as power electronics to offer an energy to energy matching supply. Demand solution as opposed to the orthodox micro hydro technology which is designed to match the evening peak lighting load of a rural village. The most critical aspect of an energy storage system is the sizing of energy storage. Aspects such as storage capacity, charging time, level of discharge and life cycle of storage play critical roles in designing a system. The proposed system uses the daily energy requirement of a rural village as the basis of a system sizing and measured data from six village hydro schemes to determine the generation capacity. Through the field measurements carried out, availability of excess energy in orthodox village hydro system has been determined. A new rural energy solution based on improved energy utilization factor is proposed for both existing and new village hydro schemes. In the case of existing village hydro schemes, the recovered energy can be used to extend the energy services to several more rural households and in the case of new schemes, the solution can be used to bring down the cost of project by substantially reducing the power generation component sizes including auxiliary civil structures. u A financial analysis was carried out and the solution was found to be feasible. A pilot scale project was implemented in Dodampitiya, a rural village in the general area Opanayaka and was commissioned on 15 t h March 2007. The system is operating satisfactorily provides good opportunities to further develop the technology and requires to be closely mentioned well into the future. iii I CONTENTS PAGE DICLARATION I ASBTRACT II CONTENTS IV LIST OF TABLES VI LIST OF FIGURES VII » ACKNOWLEDGMENT VIII CHAPTER 1 INTRODUCTION 1 CHAPTER 2 VILLAGE HYDRO SYSTEMS 8 2.1 Introduction 8 2.2 Basic Components of Village Hydro Systems 8 2.3 Planning of Village Hydro Systems 10 2.4 Village Hydro Survey 15 * 2.5 Results of the Survey 16 2.6 Sample Selection on Random Sampling Method 16 2.6.1 Outcome of the sample selection 17 CHAPTER 3 VILLAGE HYDRO POWER PLANT FOR ENERGY STORAGE SYSTEMS 18 3.1 Introduction 18 • 3.2 Use of Energy Storage Systems in Other Countries 19 3.3 History of Energy Storage 22 3.4 Methods of Energy Storage 23 3.5 Components of Energy Storage Systems 25 3.6 Battery performance 30 iv CHAPTER 4 METHODOLOGY 34 4.1 Introduction 34 4.2 Methodology 34 4.2.1 Electrifying New N Number of households 37 4.2.2 Capacity Improvements 38 4.2.3 Design New Plant Capacity 39 4.3 Model Village for Analysis 40 CHAPTER 5 CASE STUDY 42 5.1 Introduction 42 5.2 Analysis of a Model Village 43 5.2.1 Basic Introduction of the Model Village 43 5.2.2 Electrifying New Households 45 5.2.3 Existing Demand Increase 51 5.2.4 New Capacity Design 52 5.3 Analysis of Energy Storage Methodology in Sample Sites 54 5.3.1 Introduction of the Selected Sites 54 5.4 Unused Energy Utilization 55 5.4.1 Electrifying New Households 55 5.4.2 Existing Demand Increase 56 5.5 Financial Analysis 57 CHAPTER 6 DISCUSSION AND CONCLUSION 61 REFERENCES 65 APPENDIX 66 LIST OF TABLES CHAPTER 2 2.1 Load factor variation 13 2.2 Summery of the village hydro survey 15 2.3 Random sample selection Table 17 2.4 Selected Sample Sites 17 CHAPTER 5 5.1 Model Village Transmission Line Loss Determination 44 5.2 Model Village Transmission Line Voltage Drop Determination for Additional Households Electrification 46 5.3 Application of Energy Storage Methodology in Model Village Transmission Line Voltage Drop Determination for new Household Electrification 47 5.4 Application of Energy Storage Methodology in Model Village to Determine the New households on Energy Consumption Variation 49 5.5 Application of Energy Storage Methodology in Model Village for New household determination due to low Battery bank efficiency 50 5.6 Application of Energy Storage Methodology in Model Village Increasing the Present Energy Demand 52 5.7 New Plant Capacity Design on Energy Storage Method 53 5.8 Selected Samples of the Village Hydro System 54 5.9 Use of stored energy for additional household 55 5.10 Use of stored energy for increasing energy demand for existing households 56 5.11 Battery Bank (2.2kW) and 3 kW Inverter Cost 57 5.12 Present Value factor Variation on energy sale 58 vi LIST OF FIGURES CHAPTER 2 2.1 Parts of a village hydro system 9 2.2 Catchments Area of a typical village hydro system 11 2.3 Estimation of average rain fall 12 CHAPTER 3 3.1 Two Generator (1kW each) Running in Parallel in Vietnam 21 3.2 Components of Energy Storage Systems 26 3.3 Total Battery Bank Capacity 400 Amp-Hours @ 12 VDC 28 3.4 Total Battery Bank Capacity 200 Amp-Hours @ 24 VDC 29 3.5 Total Battery Bank Capacity 400 Amp-Hours@ 12 VDC 29 3.6 Battery Equivalent Impedance Circuits 31 CHAPTER 4 4.1 Demand and Generation Curve 35 4.2 Schematic diagram of an energy storage system 36 4.3 Proposed Power Plant for a Model Village 40 CHAPTER 5 5.1 Model Village 43 5.2 Daily Load Curve of Pitabaddha 0.8 kW Plant 54 Vl l A C K N O W L E D G M E N T This research project was carried out under the supervision of Dr. Thusitha Sugathapala, Head, Department of Mechanical Engineering, University of Moratuwa. His leadership and guidance and valuable inputs in project milestones were of immense help in completing this at the level of a Master Degree project. I am very appreciative of his dedication and fullest co-corporation. This was carried out as a pilot project by the Energy Conservation Fund, and I was appointed the Project Manager, responsible for the entire project development activities. I am very grateful to Mr. Harsha Wickramasinghe, General Manager, Energy Conservation Fund for having appointed me as the Project Manager and providing me with various information and details of his personal experience in this respect as well. I would be very much grateful to Mr. M.M.R Pathmasiri, Director (Energy Management), Energy Conservation Fund and Mr. S. Fernando,(director Renewable Energy) Sri Lanka Energy Managers Association for guiding me in the right way for me to achieve my objectives from this project and for extending his fullest support in various ways get this finished in success. I wish to express my deepest gratitude to Mr Chamila Jayasekara for extending his fullest support in compilation of this report and giving his knowledge gathered from his past experience for me to finish this in professional manner. Further, I wish to extend my gratefulness to Mr. Vimal Nadeera, Programme Manager, Mrs Shalika Lankeshani, Project Engineer, Mr B. W.A Bulathgama Programm Officer and other members of the staff of the Energy Conservation Fund for having provided with daily consumption reports of Village Hydro schemes and helping me with information of previous surveys conduction this respect. viii