1. Sandy Butterfield 2006 Wind Program Peer Review May 10, 2006 Overview of the Technology & Opportunities

2. 2 2006 Wind Program Peer Review Outline of Presentation  What have we learned in the past 30 years  What’s working  What’s not  How can we meet DOE COE goals?  Gaps

3. 3 2006 Wind Program Peer Review Evolution of Commercial U.S. Wind Technology

4. 4 2006 Wind Program Peer Review What have we learned?  Couldn’t predict fatigue loads  Light weight & flexible didn’t work without good design tools  Heavy didn’t work much better  Machines still failed, especially the gearboxes  Testing was required to understand source of loads  Codes must be tuned with test data  Standards codified design process & experience  Reliability is critical

5. 5 2006 Wind Program Peer Review Reliability starts in the design High-Reliability Systems Appropriate Environmental Conditions Accurate Loads & Design Requirements Designed-in Reliability Condition Monitoring Reduced Failure Rates Improved O&M System Reliability Analysis Capability O&M Data Base Designed-in Maintainability Full-Scale Testing

6. 6 2006 Wind Program Peer Review Iterative analysis/test design process Design Detail Simulate Analyze Loads “Tune” Model Performed at system level and component level Full system Blade Controller Drive train Verification Tests

7. 7 2006 Wind Program Peer Review Standards Intimately Linked to all Product Development Phases PRODUCT VERIFICATION Design and Analysis PhaseTest and Verification Phase Conceptual Design Preliminary Design and Analysis Component Qualification Tests Performance and Prototype Loads Tests Detailed Design and Analysis Final Design Reliability Tests Design Refinements Structural Detailed Design Mech. & Electrical Design DESIGN REFINEMENT Type Certification Load Case Analysis Control & Protection System Maintenance Manual Installation Manual Operating Manual Personal Safety Manufacturing Quality Load Verification Dynamic Behavior Certification Loads Test Power Performance Dynamic Behavior Noise Safety Test Power Quality Define Certification Requirements Certification Documentation Type Testing A Few Words about Standards Standards remind us of past mistakes

8. 8 2006 Wind Program Peer Review NREL/DOE Standards Support  NREL/SNL Participation in most IEC standards committees  Support AWEA standards program –AWEA standards support contract –IEC Technical Advisory Group –AWEA national standards Small turbine standards Siting standard AGMA gearing standard

9. 9 2006 Wind Program Peer Review

10. 10 2006 Wind Program Peer Review  Need new strategy and design tools to meet DOE Cost goals

11. 11 2006 Wind Program Peer Review Trends  Lifelong O&M (“unscheduled maintenance” becoming critical)  Lighter rotors, higher tip speeds, more flexible blades (lower loads)  Twist/flap coupling  Drivetrain innovation  Controls for load reduction  Offshore design concepts incorporated into onshore turbines (load control, component placement, design for reliability, condition monitoring)

12. 12 2006 Wind Program Peer Review Can rotor improvements help the rest of the system?  WindPact Rotor study shows benefits of: –Controlling tower dynamics –Passive blade load relief through twist/flap coupling –High tip speed/low solidity blades  Need follow up system study –SeaCon Turbine study –Perform system optimization –Apply practical implementation experience

13. 13 2006 Wind Program Peer Review Can we meet the COE goals? Offshore Turbines Path to 3.5 cents/kwh, DOE onshore goal

14. 14 2006 Wind Program Peer Review What will it take?  Design code enhancements  Advanced controls  System and subsystem innovation –Rotor –Blades –Drivetrain –SeaCon system optimization conceptual studies (WindPact)  Testing

15. 15 2006 Wind Program Peer Review Gaps (according to Sandy)  Aeroacoustics (limits high speed flexible rotors & downwind option)  Aerodynamics - More accurate steady & unsteady aero models  Increasing flexibility w/o complexity, cost & failure rates  Accurate prediction of coupled dynamic rotor loads  Greater fidelity between loads codes and component design codes  MIMO Control of turbulent & extreme loads without firm measure of inputs (need robust sensor technology)  More accurate inflow characterization, especially greater than 100m.  Greater drivetrain reliability while reducing cost and weight.  Offshore dynamics codes  Offshore design basis