WIND ENERGY EXPLAINED WIND ENERGY EXPLAINED Theory, Design and Application Second Edition J. F. Manwell and J. G. McGowan Department of Mechanical and Industrial Engineering, University of Massachusetts, USA A. L. Rogers DNV – Global Energy Concepts, Washington, USA This edition first published 2009 Ó 2009 John Wiley & Sons Ltd., Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com. The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Manwell, J. F. Wind energy explained : theory, design, and application / James Manwell, Jon McGowan, Anthony Rogers. – 2nd ed. p. cm. Includes bibliographical references and index. ISBN 978-0-470-01500-1 (cloth) 1. Wind power. I. McGowan, J. G. II. Rogers, Anthony L., 1948- III. Title. TJ820.M374 2009 621.31’2136–dc22 2009033881 A catalogue record for this book is available from the British Library. ISBN 978-0-470-01500-1 (Hbk) Set in 10/12pt Times Roman by Thomson Digital, Noida, India. Printed in Great Britain by CPI Antony Rowe, Chippenham, Wiltshire. Contents About the Authors ix Preface xi Acknowledgments xiii 1 Introduction: Modern Wind Energy and its Origins 1 1.1 Modern Wind Turbines 2 1.2 History of Wind Energy 10 References 21 2 Wind Characteristics and Resources 23 2.1 Introduction 23 2.2 General Characteristics of the Wind Resource 24 2.3 Characteristics of the Atmospheric Boundary Layer 36 2.4 Wind Data Analysis and Resource Estimation 53 2.5 Wind Turbine Energy Production Estimates Using Statistical Techniques 63 2.6 Regional Wind Resource Assessment 65 2.7 Wind Prediction and Forecasting 72 2.8 Wind Measurement and Instrumentation 74 2.9 Advanced Topics 84 References 87 3 Aerodynamics of Wind Turbines 91 3.1 General Overview 91 3.2 One-dimensional Momentum Theory and the Betz Limit 92 3.3 Ideal Horizontal Axis Wind Turbine with Wake Rotation 96 3.4 Airfoils and General Concepts of Aerodynamics 101 3.5 Blade Design for Modern Wind Turbines 115 3.6 Momentum Theory and Blade Element Theory 117 3.7 Blade Shape for Ideal Rotor without Wake Rotation 121 3.8 General Rotor Blade Shape Performance Prediction 124 3.9 Blade Shape for Optimum Rotor with Wake Rotation 131 3.10 Generalized Rotor Design Procedure 133 vi Contens 3.11 Simplified HAWT Rotor Performance Calculation Procedure 138 3.12 Effect of Drag and Blade Number on Optimum Performance 139 3.13 Computational and Aerodynamic Issues in Aerodynamic Design 141 3.14 Aerodynamics of Vertical Axis Wind Turbines 145 References 153 4 Mechanics and Dynamics 157 4.1 Background 157 4.2 Wind Turbine Loads 158 4.3 General Principles of Mechanics 161 4.4 Wind Turbine Rotor Dynamics 172 4.5 Methods for Modeling Wind Turbine Structural Response 200 References 202 5 Electrical Aspects of Wind Turbines 205 5.1 Overview 205 5.2 Basic Concepts of Electrical Power 206 5.3 Power Transformers 217 5.4 Electrical Machines 219 5.5 Power Converters 237 5.6 Electrical Aspects of Variable-Speed Wind Turbines 246 5.7 Ancillary Electrical Equipment 253 References 255 6 Wind Turbine Materials and Components 257 6.1 Overview 257 6.2 Material Fatigue 257 6.3 Wind Turbine Materials 266 6.4 Machine Elements 270 6.5 Principal Wind Turbine Components 276 References 308 7 Wind Turbine Design and Testing 311 7.1 Overview 311 7.2 Design Procedure 312 7.3 Wind Turbine Topologies 316 7.4 Wind Turbine Standards, Technical Specifications, and Certification 322 7.5 Wind Turbine Design Loads 325 7.6 Load Scaling Relations 333 7.7 Power Curve Prediction 336 7.8 Computer Codes for Wind Turbine Design 340 7.9 Design Evaluation 345 7.10 Wind Turbine and Component Testing 346 References 355 Contents vii 8 Wind Turbine Control 359 8.1 Introduction 359 8.2 Overview of Wind Turbine Control Systems 364 8.3 Typical Grid-connected Turbine Operation 370 8.4 Supervisory Control Overview and Implementation 374 8.5 Dynamic Control Theory and Implementation 382 References 404 9 Wind Turbine Siting, System Design, and Integration 407 9.1 General Overview 407 9.2 Wind Turbine Siting 408 9.3 Installation and Operation Issues 416 9.4 Wind Farms 419 9.5 Wind Turbines and Wind Farms in Electrical Grids 433 References 446 10 Wind Energy Applications 449 10.1 General Overview 449 10.2 Distributed Generation 450 10.3 Hybrid Power Systems 450 10.4 Offshore Wind Energy 461 10.5 Operation in Severe Climates 478 10.6 Special Purpose Applications 480 10.7 Energy Storage 489 10.8 Fuel Production 497 References 501 11 Wind Energy System Economics 505 11.1 Introduction 505 11.2 Overview of Economic Assessment of Wind Energy Systems 506 11.3 Capital Costs of Wind Energy Systems 511 11.4 Operation and Maintenance Costs 519 11.5 Value of Wind Energy 521 11.6 Economic Analysis Methods 530 11.7 Wind Energy Market Considerations 539 References 543 12 Wind Energy Systems: Environmental Aspects and Impacts 547 12.1 Introduction 547 12.2 Avian/Bat Interaction with Wind Turbines 549 12.3 Visual Impact of Wind Turbines 556 12.4 Wind Turbine Noise 561 12.5 Electromagnetic Interference Effects 573 12.6 Land-Use Environmental Impacts 582 12.7 Other Environmental Considerations 585 References 589 viii Contens Appendix A Nomenclature 593 A.1 Note on Nomenclature and Units 593 A.2 Chapter 2 593 A.3 Chapter 3 595 A.4 Chapter 4 597 A.5 Chapter 5 601 A.6 Chapter 6 604 A.7 Chapter 7 606 A.8 Chapter 8 607 A.9 Chapter 9 608 A.10 Chapter 10 610 A.11 Chapter 11 612 A.12 Chapter 12 613 A.13 Abbreviations 614 Appendix B Problems 617 B.1 Problem Solving 617 B.2 Chapter 2 Problems 617 B.3 Chapter 3 Problems 621 B.4 Chapter 4 Problems 628 B.5 Chapter 5 Problems 632 B.6 Chapter 6 Problems 637 B.7 Chapter 7 Problems 639 B.8 Chapter 8 Problems 642 B.9 Chapter 9 Problems 647 B.10 Chapter 10 Problems 652 B.11 Chapter 11 Problems 656 B.12 Chapter 12 Problems 658 Appendix C Data Analysis and Data Synthesis 661 C.1 Overview 661 C.2 Data Analysis 661 C.3 Data Synthesis 671 References 675 Index 677 About the Authors James Manwell is a professor of Mechanical Engineering at the University of Massachusetts and the Director of the Wind Energy Center there. He holds an M.S. in Electrical and Computer Engineering and a Ph.D. in Mechanical Engineering. He has been involved with a wide range of wind energy research areas since the mid 1970’s. These range from wind turbine dynamics to wind hybrid power systems. His most recent research has focused on the assessment of external conditions related to the design of offshore wind turbines. He has participated in activities of the International Energy Agency, the International Electrotechnical Commission and the Interna- tional Science Panel on Renewable Energies. He lives in Conway, Massachusetts. Jon McGowan is a professor of Mechanical Engineering at the University of Massachusetts and the co-Director of the Wind Energy Center there. He holds an M.S. and a Ph.D. in Mechanical Engineering. During his forty plus years at the University he has developed and taught a number of fundamental undergraduate/ graduate engineering courses in renewable energy and energy conversion. His research and graduate student supervision at UMass has produced approximately 200 technical papers in a wide range of energy conversion applications. His recent research interests in wind engineering have been concentrated in the areas of wind system siting, hybrid systems modeling, economics, and offshore wind engineering. Professor McGowan is a Fellow of the American Society of Mechanical Engineers (ASME) and editor of Wind Engineering journal. He lives in Northfield, Massachusetts. Anthony Rogers holds both and M.S. and Ph.D. in Mechanical Engineering from the University of Massachusetts and was formerly a senior research engineer in the Renewable Energy Research Laboratory (now the Wind Energy Center) there. He is presently a senior engineer at DNV Global Energy Concepts. He has had a long career in the wind energy field, and has been involved with a wide range of topics.