Sandy ButterfieldSandy Butterfield

2006 Wind Program Peer Review2006 Wind Program Peer Review

May 10, 2006May 10, 2006

Overview of the Technology & Overview of the Technology & OpportunitiesOpportunities

22006 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

32006 Wind Program Peer Review

Evolution of Commercial U.S. Wind Technology

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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

52006 Wind Program Peer Review

Reliability starts in the design

High-ReliabilitySystems

Appropriate Environmental

Conditions

Accurate Loads &Design Requirements

Desig

ned-in

Reliabilit

y

Condition M

onitorin

g

Reduced Failure Rates Improved O&M

System

Reliab

ility A

nalysis

Cap

ability

O&M Data Base

Designed-in

Maintainability

Fu

ll-Scale

Te stin

g

62006 Wind Program Peer Review

Iterative analysis/test design process

Design Design DetailDetail

SimulateSimulate

Analyze Analyze LoadsLoads

““Tune” Tune” ModelModel

Performed at system level and component level •Full system•Blade•Controller•Drive train

Verification Verification TestsTests

72006 Wind Program Peer Review

Standards Intimately Linked to all Product Development Phases

PRODUCT VERIFICATION

Design and Analysis Phase Test and Verification Phase

ConceptualDesign

Preliminary Design and Analysis

ComponentQualification Tests

Performance andPrototype

Loads Tests

Detailed Design and Analysis

Final Design

Reliability TestsDesign

Refinements

Structural Detailed DesignMech. & Electrical Design

DESIGN REFINEMENT

Type Certification

Load Case AnalysisControl & Protection System

Maintenance ManualInstallation ManualOperating ManualPersonal SafetyManufacturing Quality Load Verification

Dynamic Behavior

Certification Loads Test

Power PerformanceDynamic BehaviorNoiseSafety TestPower Quality

Define Certification Requirements

Certification Documentation Type Testing

A Few Words about StandardsStandards remind us of past mistakes

82006 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

92006 Wind Program Peer Review

What's Working Why 98% reported availability Design process, improved design

tools, Standards Rotor performance excellent (80% of theoretical limit)

Steady aero codes, airfoils, testing

CapEx drastically reduced Accurate design tools, load control, quality control

Blade Development Standards (design, test, certify) Product evolution strategy Stretch rotor, control loads Power quality control Power electronics

102006 Wind Program Peer Review

Need new strategy and design tools to meet DOE Cost goals

What's Not Working Why

Gearboxes bearing failures, inaccurate internal loads?

OpEx too high "unscheduled maintenance", low reliability, lack O&M automation

CapEx still too high to DOE goals

lack of fatigue load and deflection control

Rotor stretching strategy hitting limits

tower clearance limit, materials, aeroacoustics limiting tip speed, dynamic

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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)

122006 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

132006 Wind Program Peer Review

Can we meet the COE goals?

RNA Mass / Swept Area

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

40 60 80 100 120 140

Diameter (m)

Ma

ss

/sw

ep

t a

rea

(k

g/m

^2

)

WindPact Baselines

WindPact Task#5 Final

NREL Baseline 5MW

GPRA 2005 - 2025 Estimates

RePower 5MW

Enercon 6MW

V120 4.5MW

MultiBrid 5MW

GE 3.6MW

V80

V90

Siemens

Offshore Turbines

Path to 3.5 cents/kwh, DOE onshore goal

142006 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

152006 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