Onshore and Offshore Wind Energy

Vasilis Fthenakis, Founder and Director of the Center for Life Cycle Analysis, Adj. Professor of Earth and Environmental Engineering and of Electrical Engineering, Columbia University and Distinguished Scientist Emeritus, Brookhaven National Laboratory. Subhamoy Bhattacharya, Chair in Geomechanics at University of Surrey, UK, and co-founder, Director and Chief Scientific Officer of RENEW RISK, A University Spin-off. Paul A. Lynn, formerly Reader in Electrical & Electronic Engineering at Imperial College, London.

• About the Authors xiForeword xiiiPreface xvAcknowledgment to the Second Edition xviiAcknowledgment to the First Edition xviiiAbout the Companion Website xix1 Introduction 11.1 Wind energy and Planet Earth 11.2 Winds of the world 31.3 From windmills to wind turbines 71.4 Power, energy, and performance 151.5 Coming up-to-date 21Appendix 1.A: Energy units and conversions 25Co2 emissions per fuel type 25Co2 emissions in transportation 26Self-assessment questions 26Problems 27Answers to questions 27References 282 Capturing the wind 292.1 Wind speed and power 292.2 Wild wind 342.2.1 Introduction 342.2.2 Wind statistics 362.2.3 Mapping and forecasting 452.3 Predicting turbine output 51Self-assessment questions 55Problems 56Answers to questions 57References 583 Wind turbines 593.1 Turbine types and sizes 593.2 Aerodynamics 643.2.1 Rotor efficiency and the Betz limit 643.2.2 Lift and drag 673.2.3 Rotor speed 743.2.4 Rotor blades 803.2.4.1 Choosing airfoils 803.2.4.2 Stall and pitch control 833.3 Mechanics 863.3.1 Gearboxes 863.3.2 Towers 893.3.3 Vibration and fatigue 903.4 Electrics 983.4.1 Alternating current (AC) electricity 983.4.2 Generators 1063.4.2.1 Introductory 1063.4.2.2 Synchronous generators and gearless wind turbines 1113.4.2.3 Asynchronous generators 1163.5 Turbine control 1253.6 Onshore wind farms 1303.6.1 Introductory 1303.6.2 Siting and spacing 1323.6.3 Monitoring and control 136Self-assessment questions 138Problems 138Answers to questions 141References 1424 Fundamentals of offshore system 1434.1 Introduction 1434.2 Offshore wind power fundamentals 1464.3 Tackling intermittency of wind power 1494.3.1 The sun, wind, and wind-resource map 1494.3.2 Wind and waves 1524.3.3 Wind-resource maps 1564.3.4 Minimum wind speed to produce power and power curve of a turbine 1564.3.5 Storage of energy from offshore wind 1564.3.5.1 Hydrogen production using offshore wind—the Japanese “Jidai” concept 1594.3.5.2 ASIDE: potential of green hydrogen 1594.3.5.3 BATWIND project 1604.4 Offshore systems and choice of foundations 1604.4.1 Turbines and foundations 1604.5 Offshore wind farm case studies 1674.5.1 Case study: Horns Rev 2 1674.5.2 Case study: London Array 1704.5.3 Case study: World’s first floating wind farm 1734.6 Bringing the power ashore 175Appendix 4.A: Specifications of turbines 177Appendix 4.B: Details of offshore wind farms on different types of foundations 178Self-assessment questions 181Problems 181Answers to questions 182References 1835 Offshore wind farm engineering 1855.1 Conceptual design of wind arms 1865.1.1 ASIDE 1: spacing of turbines and changes in geology and water depth 1865.2 Cases studies 1885.2.1 Dogger bank offshore wind farm 1885.2.2 Westermost rough wind farm 1895.2.3 Karehamn offshore wind farm 1895.2.4 West of Duddon sands 1915.2.5 Development of offshore wind in the USA 1915.2.6 Wind farm development in China 1925.3 Detailed site investigation 1965.3.1 ASIDE 2: observed scour in Robin Rigg Wind Farm which had to be decommissioned mid-way in the lifecycle 1985.3.2 Variability in ground profiles 1985.3.3 Stages of investigation for ground model 2015.3.3.1 Geological study 2015.3.3.2 Geophysical survey 2025.3.3.3 Geotechnical investigation 2035.4 Offshore construction 2035.4.1 Introduction 2035.4.2 Choosing foundation systems 2045.5 Engineering models of wind turbine systems 2075.5.1 Load transfer mechanism from the structure to the ground 2075.5.2 Modes of vibration 2085.5.3 Mechanical model of the whole system 2105.5.3.1 Why are foundations important? 2135.6 Loads on a wind turbine structure 2135.6.1 Load cases for foundation design 2155.7 Frequencies of loads acting on wind turbine structure 2205.8 Design requirements 2225.9 Summary of offshore wind turbine engineering 224Appendix 5.A: Modes of vibrations 2245.A.1 Wind turbine systems on deep foundation 2245.A.1.1 Modes of vibration of GBS structure 225Appendix 5.B: Foundation stiffness 2255.B.1 Definition of terms (KL, K R, and KLR) through the example of a cantilever beam 226Appendix 5.C: Construction of wind and wave spectrum 2285.C.1 Construction of wind spectrum 2285.10 Kaimal spectrum 2295.11 Construction of wave spectrum 230Self-assessment questions 231Problems 232Answers to questions 235References 2366 Operations and maintenance (O&M) 2376.1 Introduction 2376.2 Maintenance practices and tools 2386.3 Wind turbine O&M data 2386.3.1 Onshore WT O&M data 2396.3.2 Offshore WT O&M data 2436.3.3 Onshore and offshore O&M data analysis 2436.3.4 The impact of O&M on the LCOE 2476.3.4.1 Land-based WT 2476.3.4.2 Offshore wind turbines 2496.4 Statistical tools of reliability analysis 2506.4.1 Failure modes, effect, and criticality analysis (FMECA) 2516.4.1.1 Failure modes 2516.4.1.2 Failure causes 2516.4.1.3 Failure effects 2526.4.1.4 Criticality of failure modes 2536.4.2 Logistic regression (LR) 2546.4.3 Artificial neural networks (ANNs) 2546.5 Workforce education and training 2556.5.1 Safety training 2556.6 Summary 256Self-assessment questions 256Problems 257Answers to questions 266Appendix 6.A: Hurricanes, typhoons, and cyclones 266Appendix 6.B: Price of OWF: Normalized cost: LCOE breakdown for European wind farms 267References 2687 Grid integration 2697.1 Setting the scene—national grids 2697.2 Electricity markets and types of power generators 2737.2.1 Peaker plants 2757.2.2 Baseload plants 2777.3 Connecting to the grid 2777.3.1 Grid strength and fault levels 2777.4 Electrical quality 2817.5 Large-scale wind power 2847.6 Intermittency and variability 2857.7 Grid-friendly wind power plants 2887.8 Capacity credit and backup generation 2897.9 The variability challenge and solutions 2907.9.1 Geographical diversity/transmission interconnections 2917.9.2 Long-distance transmission lines 2917.9.3 Grid flexibility 2927.10 Are 100% renewable energy grids feasible? 2937.11 Grid reliability 2947.12 The grid of the future 296Self-assessment questions 296Problems 297Answers to questions 299References 3008 Wind energy growth and sustainability (cost, resources, environment) 3018.1 Affordability 3028.1.1 Upfront capital and installation costs 3028.1.1.1 Onshore wind turbines 3038.1.1.2 Offshore wind turbines 3048.1.2 Operation, maintenance, and cash flow 3078.1.2.1 Levelized cost of electricity (LCOE) 3098.2 Resource availability 3118.2.1 Raw material primary resources 3128.2.1.1 Blades 3138.2.1.2 Rare earth elements (REE) 3138.2.2 Wind turbine decommissioning 3148.2.3 Wind turbine recycling 3148.2.3.1 Blades 3148.2.3.2 Rare earth elements (REE) 3168.3 Environmental and social aspects 3178.4 Land use 3208.5 Water use 3228.6 Life-cycle analysis 3228.7 Landscape and amenity 3258.8 Birds and bats 3298.9 Farming 3328.10 Seabirds, fish, and marine conservation 333Self-assessment questions 335Problems 336Answers to questions 337References 337Index 339