1 Introduction 1.1 Key features of small hydro schemes 2 Scheme identification 2.1 Preliminary study 2.1.1 Cost estimates 2.2 Feasibility study 2.2.1 Site survey 2.2.2 Hydrology 2.2.3 Geology 2.2.4 Environmental assessment 2.2.5 Preliminary estimates 2.2.6 Preliminary report 3 Refining the design 3.1 Hydrology 3.2 Geology 3.3 Headworks 3.3.1 Spillway options 3.3.2 Intakes 3.3.3 Canal design 3.4 Penstocks and intakes3.4.1 Penstock intakes 3.4.2 Steel penstocks 3.4.3 Wood stave penstocks 3.4.4 Plastic and GRP penstocks 3.5 Turbine selection 3.5.1 Low head turbines 3.5.2 Medium head turbines 3.5.3 High head turbines 3.6 Powerhouse arrangement 3.7 Useful spreadsheets 3.8 Preliminary financial analysis 3.9 Outside financing 3.9.1 "Bankable'' feasibility study 3.9.2 Economic and financial analysis 4 Detailed design of intake works, canals and penstocks 4.1 Environmental factors 4.2 Final optimisation 4.2.1 Technical optimisation 4.2.2 "Alab'' computer program 4.2.3 "Hydrohelp'' computer program 4.3 Intakes at low weirs 4.3.1 Coanda screen 4.3.2 Streambed intake 4.3.3 Bypassing 4.3.4 Settling basin 4.4 Conventional intakes4.4.1 Screen cleaners 4.4.2 Intake gates 4.4.3 Penstock filling 4.4.4 Additional information on intakes 4.5 Spillways 4.5.1 Flap (fish belly) gates 4.5.2 Obermeyer gates 4.5.3 Radial gates 4.6 Bypass gates 4.7 Stoplogs and bulkheads 4.8 Canal regulating gates 4.9 Additional information on gates 4.10 Canals 4.10.1 Controlling leakage 4.10.2 Small unlined canals 4.10.3 Canal linings 4.10.4 Under drainage 4.10.5 Further information 4.11 Penstocks and water hammer 4.11.1 Water hammer 4.11.2 Steel penstocks 4.11.3 Glass reinforced plastic (GRP) penstocks 4.11.4 HDPE and PVC penstocks 4.12 Surface treatment and painting of steelwork 5 Turbine selection 5.1 Introduction 5.2 Number of turbines 5.3 Particulate erosion 5.4 Kaplan and Francis turbines 5.4.1 Guide vanes 5.4.2 Guide vane actuation 5.4.3 Cavitation 5.4.4 Hydraulic stability and rough running 5.5 Low head turbines 5.5.1 Dimensions of Kaplan turbines 5.5.2 Vertical Kaplan turbines 5.5.3 Bulb turbines 5.5.4 Pit turbines 5.5.5 Matrix turbines 5.5.6 Axial Kaplan turbines 5.5.7 Open flume Kaplan turbines 5.5.8 Very low head turbines 5.5.9 Stoplogs and emergency isolation 5.6 Medium head turbines 5.6.1 Dimensions of Francis turbines 5.6.2 Air admission 5.6.3 Vertical Francis turbines 5.6.4 Horizontal Francis turbines 5.6.5 Twin horizontal Francis turbines 5.6.6 Inlet valves 5.6.7 Relief valves 5.6.8 Bypass valves 5.7 Pelton turbines 5.7.1 Dimensions of Pelton turbines 5.7.2 Pelton turbine arrangement 5.7.3 Pelton turbine runners 5.7.4 Pelton turbine options 5.7.5 Turgo turbines 5.8 Governing systems 6 Generators 6.1 Overspeed 6.2 Synchronous generators 6.2.1 Stators 6.2.2 Corona6.2.3 Excitation systems 6.2.4 Neutral earthing 6.2.5 Lightning protection 6.2.6 Generator cooling 6.2.7 Overspeed testing 6.2.8 Increasing generator inertia 6.2.9 Bearings 6.2.10 PTFE bearings 6.2.11 Bearing cooling and monitoring 6.2.12 Induction generators 7 Electrical systems 7.1 Single line diagram 7.1.1 Transformers 7.1.2 Station earthing7.1.3 Transmission 7.2 Control 7.2.1 Control philosophy 7.2.2 Communications 7.2.3 Programmable Logic Controllers 7.2.4 Programming instructions 7.3 Protection and instrumentation 7.4 Synchronising 8 Auxiliary plant 8.1 Auxiliary AC power supplies 8.2 DC power supplies 8.3 Water piping 8.4 Sump pumping 9 Specifications and contracts 9.1 Conditions of contract 9.1.1 General Conditions of Contract 9.2 Specifications for major generating plant 9.2.1 Turbine specifications 9.2.2 Governing systems 9.2.3 Inlet and bypass valves 9.2.4 Generator specifications 9.2.5 Tender schedules 9.2.6 Sample specifications 9.3 Specifications for other mechanical and electrical plant 9.4 Surface preparation and painting 9.4.1 Background 9.4.2 Specification requirements 9.5 Assessment of tenders 10 Powerhouse layout and design 11 Construction and commissioning 11.1 Project construction 11.2 Commissioning 12 Operation12.1 Generating plant12.2 Civil works 12.3 Safety and environmental requirements 13 Lessons from failures 13.1 Civil engineering failures 13.1.1 Ruahihi canal collapse 13.1.2 Wheao canal and head-pond breach 13.1.3 Aniwhenua canal leak 13.1.4 Lessons from civil engineering failures 13.2 Generating plant failures 13.2.1 Station in the Pacific, 1990 13.2.2 Mangahao power station 13.2.3 Tuai power station 13.2.4 Duffers power station 14 Appendix 1: Useful spreadsheets and computer programs 14.1 Hydro scheme data and cost estimates 14.2 Intake screen head losses 14.3 Turbine dimensions 14.4 Cost estimates for turbines and generators 14.5 Financial analysis 15 Appendix 2: Financial and economic considerations 15.1 Objectives of financial analysis 15.2 Objectives of economic analysis 15.3 Approach and methodology 15.3.1 Financial evaluation 15.3.2 Levelized Cost of Electricity 15.3.3 Overview of economic cost benefit analysis 16 Appendix 3: Environmental issues with two hydropower schemes 16.1 Aniwhenua 16.2 Onekaka 17 Appendix 4: Making the most of hydro specifications 17.1 Introduction 17.2 The tenderer/contractor - an interesting species 17.3 Specifications 17.3.1 Performance specifications 17.3.2 Performance specification vs prescriptive specification 17.3.3 Getting the "A'' team 17.3.4 Life cycle cost analysis 17.3.5 Is the specification tough enough? 17.3.6 Interfacing with existing equipment 17.3.7 Warranties 17.3.8 Drawings 17.3.9 Innovation vs conservatism 17.3.10 Contract inspection 17.3.11 Works acceptance vs Site acceptance 17.3.12 Project schedule 17.4 Looking beyond the specification 17.4.1 Educating our masters 17.4.2 Legal advice 17.4.3 Commercial advice and instruction 17.4.4 General Conditions of Contract 17.4.5 Special Conditions of Contract 17.4.6 Instructions to tenderers 17.4.7 Partnering 17.4.8 Tender evaluation 17.5 Conclusion References Subject index Contents of CD
Bryan Leyland trained in New Zealand and then went overseas for nine years. During this time he worked on power projects all over the world. He returned to New Zealand in 1970 to work for Lloyd Mandeno, an outstanding hydropower engineer. In 1974 Bryan set up his own consulting firm and spent most of the next 25 years working on the overall and detailed design and commissioning of 26 small hydropower schemes totaling 250 MW and the refurbishment of 27 schemes in New Zealand and overseas. Ten of the scheme won awards as "engineering projects of outstanding technical significance". On three occasions he was involved in the repair and recommissioning of schemes that had suffered catastrophic failures. This gave him a valuable insight into the need for high quality geotechnical and civil engineering. He has also acted as a consultant to the World Bank and to the Asian Development Bank on hydropower investigations and on dam safety. He has written many papers on hydropower development, power systems and electricity markets. In 2009 he was listed by Waterpower and Dam Construction as one the 60 most influential people in the hydropower industry worldwide.
We are a group of individual investors who are trying to tap into the small hydro space. At the moment we are working on two small hydro schemes. None of us are engineers by trade, so our strategy has been to lean heavily on a reputable consultant with experience and know-how. (...) Now that the consultant is entering into the tender drawings phase, We are trying to raise many of the design considerations highlighted in this book to them. As we debate each item, I cannot help but feel extremely relieved to have bought and read this book. At the very least, even though we are led by our consultant on the designs, we are not completely blind and have working knowledge to influence the designs.This book has been invaluable to our business. The contents in the book are having a real life impact here in our projects.I highly recommend this book to anyone who is about to enter into the small hydro space.Alan Jenviphakul The book takes you from start to finish through the evolution of a hydro scheme. From initial site assessment, hydrology, environmental, banking and finance through the many layers of detailed design work to detailed analysis of the many types and configurations of turbine plant and generators available.Small Hydroelectric Engineering Practice is a thoroughly readable and enjoyable book for anyone interested in small hydro. It is an essential book for anyone working with small hydro whether a first time developer or an experienced hydro engineer.Dave MacKay, Inchbonnie Hydro, New ZealandA book, based on tradition, full of experience and presenting recent developments. Supported by many pictures, sketches and tables it is very comfortable to read and to learn in one run. Several pages dedicated to "learning from failures" and operational recommendations should be highlighted. A "must" in the library of a hydropower engineer!Prof. Dr Bernhard Pelikan, University of Natural Resources and Applied Life Sciences, Vienna, Austria;Vice President of the European Small Hydropower AssociationThis is a unique and comprehensive collection of practical engineering advice that should be essential reading for anyone involved in the development of a small to medium sized hydro-electricity resource. It covers all engineering disciplines and is based on a lifetime of involvement in this industry by the author. He should be commended for sharing both ingenious design solutions and the sometimes painful lessons learned, with others who might be fortunate enough to also be involved in harnessing these often overlooked renewable energy resources.Ir. W.L. Mandeno, FIPENZ, CPEng, Int.PE.Wellington, NZ By systematically explaining the different scheme components, Mr Leyland's book caters to a range of readers and keeps the book highly readable. He explained logically about the important decisions required when developing a scheme and suggests how to avoid repeating past mistakes. This lays the foundation for the subsequent detailed discussions including job specifications, contracts for procurement and installation.The book also includes a CD of eight spreadsheets to assist consultants, engineers, owners and development of small hydro electricity schemes. It reads well using clear, conversational language to explain a complex subject without a lot of jargon. As a fellow hydropower enthusiast, I believe this book is an excellent reference.Robert Shelton, MIPENZ