Innovation in Wind Turbine Design -- Contents -- Acknowledgements -- Foreword -- Preface -- Introduction -- 0.1 Why Innovation? -- 0.2 The Challenge of Wind -- 0.3 The Specification of a Modern Wind Turbine -- 0.4 The Variability of the Wind -- 0.5 Commercial Wind Technology -- 0.6 Basis of Wind Technology Evaluation -- 0.6.1 Standard Design as Baseline -- 0.6.2 Basis of Technological Advantage -- 0.6.3 Security of Claimed Power Performance -- 0.6.4 Impact of Proposed Innovation -- References -- Part I DESIGN BACKGROUND -- 1 Rotor Aerodynamic Theory -- 1.1 Introduction -- 1.2 Aerodynamic Lift -- 1.3 The Actuator Disc -- 1.4 Open Flow Actuator Disc -- 1.4.1 Axial Induction -- 1.4.2 Momentum -- 1.5 Generalised Actuator Disc Theory -- 1.6 The Force on a Diffuser -- 1.7 Generalised Actuator Disc Theory and Realistic Diffuser Design -- 1.8 Why a Rotor? -- 1.9 Basic Operation of a Rotor -- 1.10 Blade Element Momentum Theory -- 1.10.1 Momentum Equations -- 1.10.2 Blade Element Equations -- 1.11 Optimum Rotor Theory -- 1.11.1 The Power Coefficient, Cp -- 1.11.2 Thrust Coefficient -- 1.11.3 Out-of-Plane Bending Moment Coefficient -- 1.12 Generalised BEM -- 1.13 Limitations of Actuator Disc and BEM Theory -- 1.13.1 Actuator Disc Limitations -- 1.13.2 Wake Rotation and Tip Effect -- 1.13.3 Optimum Rotor Theory -- 1.13.4 Skewed Flow -- 1.13.5 Summary -- References -- 2 Rotor Aerodynamic Design -- 2.1 Optimum Rotors and Solidity -- 2.2 Rotor Solidity and Ideal Variable Speed Operation -- 2.3 Solidity and Loads -- 2.4 Aerofoil Design Development -- 2.5 Sensitivity of Aerodynamic Performance to Planform Shape -- 2.6 Aerofoil Design Specification -- References -- 3 Rotor Structural Interactions -- 3.1 Blade Design in General -- 3.2 Basics of Blade Structure -- 3.3 Simplified Cap Spar Analyses -- 3.3.1 Design for Minimum Mass with Prescribed Deflection.

3.3.2 Design for Fatigue Strength: No Deflection Limits -- 3.4 The Effective t/c Ratio of Aerofoil Sections -- 3.5 Blade Design Studies: Example of a Parametric Analysis -- 3.6 Industrial Blade Technology -- 3.6.1 Design -- 3.6.2 Manufacturing -- 3.6.3 Design Development -- References -- 4 Upscaling of Wind Turbine Systems -- 4.1 Introduction: Size and Size Limits -- 4.2 The 'Square-Cube' Law -- 4.3 Scaling Fundamentals -- 4.4 Similarity Rules for Wind Turbine Systems -- 4.4.1 Tip Speed -- 4.4.2 Aerodynamic Moment Scaling -- 4.4.3 Bending Section Modulus Scaling -- 4.4.4 Tension Section Scaling -- 4.4.5 Aeroelastic Stability -- 4.4.6 Self Weight Loads Scaling -- 4.4.7 Blade (Tip) Deflection Scaling -- 4.4.8 More Subtle Scaling Effects and Implications -- 4.4.9 Gearbox Scaling -- 4.4.10 Support Structure Scaling -- 4.4.11 Power/Energy Scaling -- 4.4.12 Electrical Systems Scaling -- 4.4.13 Control Systems Scaling -- 4.4.14 Scaling Summary -- 4.5 Analysis of Commercial Data -- 4.5.1 Blade Mass Scaling -- 4.5.2 Shaft Mass Scaling -- 4.5.3 Scaling of Nacelle Mass and Tower Top Mass -- 4.5.4 Tower Top Mass -- 4.5.5 Tower Scaling -- 4.5.6 Gearbox Scaling -- 4.6 Upscaling of VAWTs -- 4.7 Rated Tip Speed -- 4.8 Upscaling of Loads -- 4.9 Violating Similarity -- 4.10 Cost Models -- 4.11 Scaling Conclusions -- References -- 5 Wind Energy Conversion Concepts -- References -- 6 Drive Train Design -- 6.1 Introduction -- 6.2 Definitions -- 6.3 Objectives of Drive Train Innovation -- 6.4 Drive Train Technology Maps -- 6.5 Direct Drive -- 6.6 Hybrid Systems -- 6.7 Hydraulic Transmission -- 6.8 Efficiency of Drive Train Components -- 6.8.1 Introduction -- 6.8.2 Efficiency Over the Operational Range -- 6.8.3 Gearbox Efficiency -- 6.8.4 Generator Efficiency -- 6.8.5 Converter Efficiency -- 6.8.6 Transformer Efficiency -- 6.8.7 Fluid Coupling Efficiency.

6.9 The Optimum Drive Train -- 6.10 Innovative Concepts for Power Take-Off -- References -- 7 Offshore Wind Turbines -- 7.1 Design for Offshore -- 7.2 High Speed Rotor -- 7.2.1 Design Logic -- 7.2.2 Speed Limit -- 7.2.3 Rotor Configurations -- 7.2.4 Design Comparisons -- 7.3 'Simpler' Offshore Turbines -- 7.4 Offshore Floating Turbine Systems -- References -- 8 Technology Trends Summary -- 8.1 Evolution -- 8.2 Consensus in Blade Number and Operational Concept -- 8.3 Divergence in Drive Train Concepts -- 8.4 Future Wind Technology -- 8.4.1 Introduction -- 8.4.2 Airborne Systems -- 8.4.3 New System Concepts -- References -- Part II TECHNOLOGY EVALUATION -- 9 Cost of Energy -- 9.1 The Approach to Cost of Energy -- 9.2 Energy: The Power Curve -- 9.3 Energy: Efficiency, Reliability, Availability -- 9.3.1 Efficiency -- 9.3.2 Reliability -- 9.3.3 Availability -- 9.4 Capital Costs -- 9.5 Operation and Maintenance -- 9.6 Overall Cost Split -- 9.7 Scaling Impact on Cost -- 9.8 Impact of Loads (Site Class) -- References -- 10 Evaluation Methodology -- 10.1 Key Evaluation Issues -- 10.2 Fatal Flaw Analysis -- 10.3 Power Performance -- 10.3.1 The Betz Limit -- 10.3.2 The Pressure Difference across a Wind Turbine -- 10.3.3 Total Energy in the Flow -- 10.4 Drive Train Torque -- 10.5 Representative Baseline -- 10.6 Design Loads Comparison -- 10.7 Evaluation Example: Optimum Rated Power of a Wind Turbine -- 10.8 Evaluation Example: The Carter Wind Turbine and Structural Flexibility -- 10.9 Evaluation Example: Concept Design Optimisation Study -- References -- Part III DESIGN THEMES -- 11 Optimum Blade Number -- 11.1 Energy Capture Comparisons -- 11.2 Blade Design Issues -- 11.3 Operational and System Design Issues -- 11.4 Multi Bladed Rotors -- References -- 12 Pitch versus Stall -- 12.1 Stall Regulation -- 12.2 Pitch Regulation -- 12.3 Fatigue Loading Issues.

12.4 Power Quality and Network Demands -- 12.4.1 Grid Code Requirements and Implications for Wind Turbine Design -- References -- 13 HAWT or VAWT? -- 13.1 Introduction -- 13.2 VAWT Aerodynamics -- 13.3 Power Performance and Energy Capture -- 13.4 Drive Train Torque -- 13.5 Niche Applications for VAWTs -- 13.6 Status of VAWT Design -- 13.6.1 Problems -- 13.6.2 Solutions? -- References -- 14 Free Yaw -- 14.1 Yaw System COE Value -- 14.2 Yaw Dynamics -- 14.3 Yaw Damping -- 14.4 Main Power Transmission -- 14.5 Operational Experience of Free Yaw Wind Turbines -- 14.6 Summary View -- References -- 15 Multi Rotor Systems -- 15.1 Introduction -- 15.2 Standardisation Benefit and Concept Developments -- 15.3 Operational Systems -- 15.4 Scaling Economics -- 15.5 History Overview -- 15.6 Aerodynamic Performance of Multi Rotor Arrays -- 15.7 Recent Multi Rotor Concepts -- 15.8 Multi Rotor Conclusions -- References -- 16 Design Themes Summary -- Part IV INNOVATIVE TECHNOLOGY EXAMPLES -- 17 Adaptable Rotor Concepts -- 17.1 Rotor Operational Demands -- 17.2 Control of Wind Turbines -- 17.3 Adaptable Rotors -- 17.4 The Coning Rotor -- 17.4.1 Concept -- 17.4.2 Coning Rotor: Outline Evaluation - Energy Capture -- 17.4.3 Coning Rotor: Outline Evaluation - Loads -- 17.4.4 Concept Overview -- 17.5 Variable Diameter Rotor -- References -- 18 A Shrouded Rotor -- References -- 19 The Gamesa G10X Drive Train -- 20 Gyroscopic Torque Transmission -- References -- 21 The Norsetek Rotor Design -- References -- 22 Siemens Blade Technology -- 23 Stall Induced Vibrations -- References -- 24 Magnetic Gearing and Pseudo-Direct Drive -- 24.1 Magnetic Gearing Technology -- 24.2 Pseudo-Direct Drive Technology -- References -- 25 Summary and Concluding Comments -- Index.