Large Blade Testing FacilityLARGE WIND TURBINES

Rahul YaralaExecutive Director, Wind Technology Testing Center

May 12, 2011

WHY OFFSHORE WIND?

• Resource near load centers• Minimize greenhouse gas emissions from

electricity generation• Minimal water consumption for electricity

generation• Energy Independence• Green Jobs and local economic

development

• Higher Capacity Factors• Low shear and turbulence• Higher wind speeds• Turbines can spin at higher tip speeds

and hence higher energy production

A POWERFUL RESOURCE IN US

WHY LARGER TURBINES?

CHALLENGES and OPPORTUNITIES

• Rotor Blade Structure• New materials• Two-piece• Larger Chords

• New Tower concepts• Composite materials• Lighter and corrosion resistance

• Drivetrain• Direct drive or low speed

• Foundations

• Corrosion protection

• Site specific wind data collection and correlation with mesoscale weather prediction models for wind assessment.

• Further research and data collection using newer offshore friendly technology like LIDAR, SODAR etc… is very important

• Demonstration platforms or prototype farms are required for offshore wind specific technology development and long term cost competitiveness of offshore wind. This is similar to land based turbine testing at NREL and UK’s (public-private) initiative to have 100MW offshore wind farm available for prototyping and testing.

CHALLENGES and OPPORTUNITIES

• Static strength testing and accelerated fatigue testing of wind turbine blades are required for • Turbine certification

• Reduce the risk of widespread failures

• Improve blade reliability• Reduce COE

• Blades over 50m can not be fatigue tested in the United States

• Blades 62m long are in production and longer blades are being designed

• This project will reduce COE by • Reducing frequency of blade failures

• Lowering machine cost

• Introducing more efficient blades

• Reducing technical and financial risk of large-scale deployment

• Providing industry with low cost test facilities to comply with certification requirements and support value engineering

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NWTC IUF Blade Test Facility built for blades up to 34m

NWTC Blade Test Facility modified to test blades up to 50m

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.75 MW

3.6 MW

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7 MW

BLADES - Statement of the Problem

Slide courtesy of Jason Cotrell of NREL

Development of Test Equipment• Procuring a state of the art hydraulic based static test system from MTS• Working with MTS to scale up NREL UREX Fatigue Test System• Designing and procuring a new generation of the NREL data acquisition hardware• Developing a new version of data acquisition software

Schematic of MTS Static Test SystemCourtesy of MTS website

Technical Approach

Slide courtesy of Jason Cotrell of NREL

Picture courtesy of MTS and NREL

Static and Fatigue Testing

•Latest hydraulic actuators/winches will allow matching various specified bending moment distributions.

•Dual-axis resonant test system (NREL patent pending)

THANK YOU