Managing Turbine Operating Costs Through Comprehensive and Targeted Rotor Blade Inspections

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

Mike Jeffrey, Complete Wind Corporation

• A balanced design considering both Aerodynamic and Structural requirements

Rotor Blade 101

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON 2

• Rotor blades are very large, manually constructed composite structures serving as the primary driver • MW Class Rotor Blades: 34m – 83.5m +

1 – Wang , Brian (4/15/2011) . 20MW Wind Turbine Designs based on Modified Conventional Designs could be built by 2020, Retrieved: March 26, 2013, from http://nextbigfuture.com/2011/04/20-megawatt-wind-turbine-designs-based.html

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• Rotor blades are generally made from Fibre Reinforced Plastic (FRP) with either a wood or plastic core

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2 – Cho, James (7/14/2005). Airfoil, Retrieved: March 27, 2013, from http://en.wikipedia.org/wiki/Airfoil

Why Perform Rotor Blade Inspections? • Blades are typically designed for a 20 year

service life • Blades are WEAR components that require

routine inspection and repair • Insufficient inspection/service will lead to costly

blade repair and potential unplanned replacement

• Manufacturer variability – due diligence

3 CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

Critical Areas for Inspection

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• Bond-lines: SW(s), LE and TE in particular Max Chord • Root and Flange Area • Tip (bottom 1/3 of LE) and Aerodynamic Elements • Main Structural Components • Sandwich Structure (in particular Max Chord)

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

What is Involved? Inspection Type Frequency Primary Findings

Exterior From Ground Annually Exterior Wear/Operational defects, Lightning Strikes, Serious Manufacturing Anomalies

Up-tower Interior/Exterior Prior to End of Warranty, subsequent, every 3 – 5 years

Interior & Exterior Wear/Operational defects, Interior and Exterior Manufacturing Anomalies

Lightning Protection System

Following OEM or IEC 61400-24 recommendations

Confirmation of down conductor connection, receptor inspection

Dynamic Rotor Balancing At commissioning , subsequent tests every 3 - 5 years

Mass and Aerodynamic Imbalance

5 CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

What is a Wear Related Defect?

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Some common wear/operational related defects: 1. LE Erosion 2. Cracking along Bondlines and/or Blade Shells 3. Lightning Strike Damage

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

A wear/operational related defect is: • Resulting from the operation of the turbine • Resulting from Force Majeure

What is a Manufacturing Defect?

7 CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

A manufacturing defect is: • Resulting from the manufacturing process • Resulting from the rotor blade design

Some common Manufacturing defects: 1. Wrinkles 2. Dry Spots in Laminate 3. Bondline Voids

CWC Inspection Statistics

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The findings of inspections performed between 2008 and the present were used to establish general inspection trends. • # of Blades in Sample Population: 4,860 • # of Turbine Manufacturers: 7 • Turbine Size: 0.66MW – 3.0MW • % of Population Identified with Defects: ~85% • Average number of defects per blade: ~10 • All statistics shown in charts are relative to number of blades affected not relative to defects per blade

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

Defect Type Breakdown

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Total # of Defects discovered through Inspections: 48,371

Defects were categorized by the following: 1. Manufacturer (~52%)

a. Fabrication b. Serial

2. Wear (~44%) 3. Transport/

Construction (~3%) 4. Other (~0%) CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

52% 44%

3%

0.26%

% Defects Mfg % Defect Wear % Defects Transport % Defects Other

Defect by Manufacturer

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Inspections performed on 7 different Turbine Manufacturers:

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

No Defect TransportConstruction

Defects

Wear Defects FabricationDefects

Serial Defects Other

% of Blades

MFG A

MFG B

MFG C

MFG D

MFG E

MFG F

MFG G

Defect by Turbine Lifecycle

11 CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

No Defect TransportConstruction

Defects

Wear Defects FabricationDefects

Serial Defects Other

% of Blades

Incoming

End of Warranty

Post Warranty

What are the Lessons Learned?

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON 12

End of Warranty Inspections: • End of Warranty Inspections are generally the last

opportunity the Owner and Operator has to place costs for repair on the Original Equipment Manufacturer

• >50% of rotor blades inspected at End of Warranty were found to have Manufacturing Related Fabrication Defects

• Most won’t complete thorough inspections on 100% of their wind farm It is imperative that inspections are timed to allow

for inspection of 100% of the Wind Farm in the event of serial defect discovery

What are the Lessons Learned?

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON 13

Wear Defects: • ~100% of rotor blades inspected Post Warranty were

found to have wear defects • >90% of rotor blades inspected at End of Warranty were

found to have wear defects • Almost all of the costs for repair of these defects will be the

responsibility of the Owner and Operators • Ensure that proper allowances are made for these costs

when planning and budgeting

What are the Lessons Learned?

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON 14

Transport and Construction: • ~25% of rotor blades inspected during incoming inspection

were found with transport and construction related defects • ~15% of rotor blades inspected at End of Warranty and

Post Warranty were found with transport and construction related defects

• Owner and operators must ensure that a representative is on site to inspect for and ensure proper completion of defect repair due to transport and construction

Conclusions

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1. Owners and Operators must ensure that proper planning and budgeting is available to allow for inspection and maintenance of rotor blades.

2. Addressing defects requiring repair early allows for efficient scheduling of repairs allowing turbines to operate more safely and remain online longer.

3. It is imperative to work with in-house expertise, the OEM and 3rd Party ISP’s to develop and establish a long term inspection and maintenance program.

CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON

Questions?

Thank you for your attention. Complete Wind’s Core Management group has: • Been active in the Wind Industry for 15+ years • Managed teams of technicians for repair, refurbishment and remediation of large scale wind turbine projects • Supported owner/operators in USA and Canada on Inspections, including but not limited to consultation with OEM • Worked collectively with owner/operators to develop a rotor blade preventative maintenance program for their own

Operations and Maintenance post warranty

16 CanWEA – Operations and Maintenance Summit – February 26th & 27th, 2015 – Toronto, ON