WIND RESOURCE ASSESSMENT WIND RESOURCE ASSESSMENT A Practical Guide to Developing a Wind Project Michael C. Brower AWS Truepower, LLC, Albany, New York, USA with contributions from Bruce H. Bailey Philippe Beaucage Daniel W. Bernadett James Doane Matthew J. Eberhard Kurt V. Elsholz Matthew V. Filippelli Erik Hale Michael J. Markus Dan Ryan Mark A. Taylor Jeremy C. Tensen A JOHN WILEY & SONS, INC., PUBLICATION Copyright © 2012 by John Wiley & Sons, Inc. 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Brower, Michael, 1960- TJ825.W555 2011 621.312136–dc23 2011040044 Printed in the United States of America 10987654321 The authors would like to thank the New York State Energy Research and Development Authority (NYSERDA) for supporting the creation of the Wind Resource Assessment Handbook (Albany, New York, USA; NYSERDA; 2010), on which parts of the present book are based. We also gratefully acknowledge the help of the following reviewers, who provided many useful comments and corrections to the manuscript: Dennis L. Elliott, Matthew Hendrickson, Ian Locker, Kathleen E. Moore, Ron Nierenberg, Andrew Oliver, Gordon Randall, Marc Schwartz, and Richard L. Simon. Notwithstanding their diligent efforts, any errors and oversights remain the sole responsibility of the authors. We would also like to thank the following staff of AWS Truepower for their assistance in preparing the manuscript: Alicia Jacobs, Alison Shang, and Amber Trendell. Their help is deeply appreciated. Michael C. Brower (ed.) Bruce H. Bailey Philippe Beaucage Daniel W. Bernadett James Doane Matthew J. Eberhard Kurt V. Elsholz Matthew V. Filippelli Erik Hale Michael J. Markus Dan Ryan Mark A. Taylor Jeremy C. Tensen CONTENTS Preface xv 1. Introduction 1 1.1 Where do Winds Come From? 2 1.2 Key Characteristics of the Wind 4 1.2.1 The Temporal Dimension 4 1.2.2 The Spatial Dimension 5 1.2.3 Other Characteristics of the Wind Resource 6 1.3 Wind Power Plants 6 1.4 Purpose and Organization of this Book 9 1.5 Questions for Discussion 10 Suggestions for Further Reading 11 PART 1 Wind Monitoring 13 2. Overview of a Wind Resource Assessment Campaign 15 2.1 Site Identification 16 2.2 Resource Monitoring 16 2.2.1 Wind Monitoring Campaign Design 17 2.2.2 Measurement Plan 18 2.2.3 Monitoring Strategy 18 2.2.4 Quality Assurance Plan 19 2.3 Wind Resource Analysis 20 2.3.1 Data Validation 20 2.3.2 Characterizing the Observed Wind Resource 20 2.3.3 Estimating the Hub Height Resource 21 2.3.4 Climate Adjustment 21 2.3.5 Wind Flow Modeling 21 2.3.6 Uncertainty in Wind Resource Assessment 21 2.3.7 Project Design and Energy Production 21 Suggestions for Further Reading 22 vii viii CONTENTS 3. Siting a Wind Project 23 3.1 Site Selection 23 3.2 Regional Wind Resource Information 25 3.2.1 Wind Resource Maps 25 3.2.2 Wind Measurements 26 3.3 Field Surveys 29 3.4 Tower Placement 30 3.4.1 Dedicated Towers 31 3.4.2 Existing Multi-Use Tall Towers 33 3.5 Permitting for Wind Monitoring 33 3.6 Land Lease Agreements 34 3.7 Questions for Discussion 35 Suggestions for Further Reading 36 4. Monitoring Station Instrumentation and Measurements 37 4.1 Basic Measurements 37 4.1.1 Horizontal Wind Speed 37 4.1.2 Wind Direction 42 4.1.3 Air Temperature 44 4.2 Additional Measurements 45 4.2.1 Vertical Wind Speed 45 4.2.2 Heated Anemometers 47 4.2.3 Delta Temperature 47 4.2.4 Barometric Pressure 47 4.2.5 Relative Humidity 48 4.2.6 Global Solar Radiation 49 4.3 Recorded Parameters and Sampling Intervals 49 4.3.1 Average 49 4.3.2 Standard Deviation 50 4.3.3 Maximum and Minimum 50 4.4 Data Loggers 50 4.5 Data Storage Devices 51 4.5.1 Data Processing and Storage 52 4.5.2 Storage Devices 52 4.6 Data Transfer Equipment 52 4.6.1 Manual Data Transfer 53 4.6.2 Remote Data Transfer 54 4.7 Power Sources 55 4.7.1 Household Batteries 55 4.7.2 Solar Battery Systems 55 4.7.3 AC Power 55 4.7.4 Other Power Options 56 4.8 Towers and Sensor Support Hardware 56 4.8.1 Towers 56 4.8.2 Sensor Support Hardware 57 CONTENTS ix 4.9 Wiring 57 4.10 Measurement System Accuracy and Reliability 58 4.10.1 Accuracy 58 4.10.2 Reliability 59 4.11 Questions for Review and Discussion 59 References 60 Suggestions for Further Reading 60 5. Installation of Monitoring Stations 61 5.1 Equipment Procurement 61 5.2 Equipment Acceptance Testing and Field Preparation 62 5.2.1 Acceptance Testing 62 5.2.2 Field Preparation Procedures 63 5.3 Installation Team 64 5.4 Safety 64 5.5 Determination of True North 65 5.6 Tower Installation 66 5.6.1 New Tilt-Up Towers 66 5.6.2 New Lattice Towers 69 5.6.3 Existing Towers 69 5.7 Sensor and Equipment Installation 70 5.7.1 Anemometers 70 5.7.2 Wind Vanes 75 5.7.3 Temperature and Other Sensors 76 5.7.4 Data Loggers and Associated Hardware 76 5.7.5 Sensor Connections and Cabling 77 5.7.6 Grounding and Lightning Protection 77 5.8 Site Commissioning 80 5.9 Documentation 81 5.10 Cost and Labor Estimates 81 5.11 Questions for Discussion 84 Suggestions for Further Reading 85 6. Station Operation and Maintenance 87 6.1 Site Visits 88 6.2 Operation and Maintenance Procedures 88 6.2.1 Project Description and Operation and Maintenance Philosophy 88 6.2.2 System Component Descriptions 88 6.2.3 Routine Instrument Care Instructions 89 6.2.4 Site Visit Procedures 90 6.3 Documentation 92 6.4 Spare Parts Inventory 93 6.5 Questions for Discussion 93 x CONTENTS 7. Data Collection and Handling 99 7.1 Raw Data Storage 99 7.1.1 Data Storage Types 100 7.1.2 Data Storage Capacity 100 7.2 Data Retrieval 101 7.3 Data Retrieval Frequency 101 7.4 Data Protection and Storage 101 7.4.1 Data Logger 101 7.4.2 Computer Hardware 102 7.4.3 Data Handling Procedures 102 7.5 Documentation 102 7.6 Questions for Discussion 103 8. Ground-Based Remote Sensing Systems 105 8.1 Sodar 106 8.2 Lidar 108 8.3 Remote Sensing Campaign Design and Siting 109 8.4 Data Collection and Processing 110 8.5 Comparisons with Conventional Anemometry 111 8.5.1 Beam Tilt (Sodar) 111 8.5.2 Vector to Scalar Wind Speed Conversion (Sodar and Lidar) 112 8.5.3 Environmental Conditions (Lidar) 112 8.5.4 Turbulence Intensity and Anemometer Overspeeding (Sodar and Lidar) 112 8.5.5 Flow Inclination and Complex Terrain (Sodar and Lidar) 113 8.5.6 Volume Averaging (Sodar and Lidar) 113 8.5.7 Distance from Reference Mast 113 8.6 Questions for Discussion 113 Suggestions for Further Reading 114 PART 2 Data Analysis and Resource Assessment 115 9. Data Validation 117 9.1 Data Conversion 118 9.2 Data Validation 119 9.2.1 Validation Routines 120 9.2.2 Treatment of Suspect Data 124 9.3 Post-Validation Adjustments 125 9.3.1 Tower Effects 125 9.3.2 Turbulence 126 9.3.3 Inclined Flow 126 9.4 Data Substitution and Averaging 127 9.4.1 Data Substitution 127 CONTENTS xi 9.4.2 Data Averaging 128 9.5 Questions for Discussion 128 References 129 Suggestions for Further Reading 129 10.