1. J McNaughton*, S Harper*, R Sinclair*, B Sellar#
07/09/2015
Measuring and Modelling the Power Curve
of a Commercial-Scale Tidal Turbine
11th EWTEC, Nantes, France
*Alstom Ocean Energy, Bristol. #University of Edinburgh

2. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 2
Overview
• Introduction
• The IEC Methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

3. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 3
Introduction
ReDAPT (Reliable Data Acquisition Platform for Tidal)
• Commissioned and funded by Energy Technologies
Institute
• Accelerate tidal energy industry
• Academic and Industrial Collaboration
• Alstom Ocean’s 1MW turbine deployed at EMEC
• Understand environment and improve modelling
• Project outcomes and reports available online:
http://www.eti.co.uk/project/redapt/

4. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 4
Introduction
ReDAPT (Reliable Data Acquisition Platform for Tidal)

5. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 5
Introduction
Performance Curves
• Measureable performance of tidal turbine
• Easy to understand, compare, sell
• Required for yield and grid predictions
• Key challenges:
−Prediction in the design stage
−Verification of the performance once operational

6. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 6
Overview
• Introduction
• The IEC Methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

7. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 7
IEC Methodology
Overview
• IEC Technical Standard (IEC/TS) 62600-200
• Basic procedure:
−Measure flow and power concurrently
−Align and process datasets
−Time average power and reference velocity
−Velocity binning
−Interpolate missing data

8. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 8
IEC Methodology
Flow profiler positioning
• Two choices for flow
profiler position
• In-line
−Single profiler for each
tide
−More representative flow
• Adjacent
−Two profilers
−Average of velocity
−Error checking
• Beam spread should be
inside the box

9. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 9
IEC Methodology
Flow profiler positioning
• Two choices for flow
profiler position
• In-line
−Single profiler for each
tide
−More representative flow
• Adjacent
−Two profilers
−Average of velocity
−Error checking
• Beam spread should be
inside the box

10. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 10
IEC Methodology
Method of bins
• Representative of power
available in the flow
Uj =
1
A
Uk,j
3
Ak
S
k=1
1/3
A = Ak
S
k=1

11. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 11
IEC Methodology
Power Curve Validity
• Minimum criteria:
−15 concurrent days
−80% turbine availability
−180 hours sampled data
−90% of swept area measured
−10 vertical bins (max bin size 1 m)
• Time averaging:
−2 – 10 minutes period
−Minimum 90% of valid data points per period
• Velocity binning:
−Maximum 0.1m/s bin size
−At least 30 minutes of time-averaged data
−Maximum 10% interpolated velocity bins
−No successive interpolated bins

12. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 12
Overview
• Introduction
• The IEC Methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

13. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 13
Tidal Bladed (DNV-GL)
Numerical Prediction
• Industry-standard Blade Element Momentum code for loads
calculations
• Key inputs:
− Hydrofoil datasets
− Drivetrain efficiencies
− Control system definition
− Environmental conditions
• Steady:
− Idealised conditions
− Fast calculations to run
• Dynamic:
− Site specific
− Several hundred representative ten-minute simulations
− Mean power weighted according to lifetime probability

14. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 14
Overview
• Introduction
• The IEC methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

15. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 15
Measured Power Curves
Flow-sensors
ADCP SBD
Sensor
name
Teledyne
RDI
Workhorse
Sentinel
Nortek
AD2CP
No. beams 4 1
Operating
frequency
600 kHz 1 MHz
Sampling
frequency
0.5 Hz 4 Hz
Bin size 1 m 0.4 m
Range 50 m 10 m

16. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 16
Data Processing
Measured Power Curves
• Seabed ADCPs processed to give reference velocity
• ADCP and power datasets are aligned and then averaged

17. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 17
Presented Power Curve
Measured Power Curves
• Significant power
fluctuations over ten-
minute sample
• Time & velocity
averaging smoothens
curve
• Flood and ebb curves
different around rated
• Numerical prediction
close to measured
curve

18. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 18
Presented Power Curve
Measured Power Curves
• Significant power
fluctuations over ten-
minute sample
• Time & velocity
averaging smoothens
curve
• Flood and ebb curves
different around rated
• Numerical prediction
close to measured
curve

19. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 19
Presented Power Curve
Measured Power Curves
• Significant power
fluctuations over ten-
minute sample
• Time & velocity
averaging smoothens
curve
• Flood and ebb curves
different around rated
• Numerical prediction
close to measured
curve

20. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 20
Presented Power Curve
Measured Power Curves
• Significant power
fluctuations over ten-
minute sample
• Time & velocity
averaging smoothens
curve
• Flood and ebb curves
different around rated
• Numerical prediction
close to measured
curve

21. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 21
Presented Power Curve
Measured Power Curves
• Significant power
fluctuations over ten-
minute sample
• Time & velocity
averaging smoothens
curve
• Flood and ebb curves
different around rated
• Numerical prediction
close to measured
curve

22. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 22
Overview
• Introduction
• The IEC Methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

23. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 23
Flow Profiler Location
Sensitivity to Reference Velocity
• Investigation into
reference velocity
from different In-line
ADCPs

24. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 24
Flow Profiler Location
Sensitivity to Reference Velocity
• Investigation into
reference velocity
from different In-line
ADCPs
• Less “power per flow
bin” for further
upstream ADCP
• Insufficient dataset to
draw firm conclusions

25. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 25
Turbine-mounted flow sensor
Sensitivity to Reference Velocity
• Nose-mounted SBD:
−Beam velocity only
−Max range 10 m

26. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 26
Turbine-mounted flow sensor
Sensitivity to Reference Velocity
• Nose-mounted SBD:
−Beam velocity only
−Max range 10 m
−Hub-height
• Calibration issue or
turbine influence?

27. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 27
Turbine-mounted flow sensor
Sensitivity to Reference Velocity
• Nose-mounted SBD:
−Beam velocity only
−Max range 10 m
−Hub-height
• Calibration issue or
turbine influence?
• Hardware & setup not
right for this use but
not the end of the
story

28. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 28
Overview
• Introduction
• The IEC Methodology
• Numerical Prediction
• Measured Power Curves
• Sensitivity to Reference Velocity
• Conclusions

29. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 29
Conclusions
• IEC/TS 62600-200:
− Robust procedure with stringent criteria
− Not easy to do, but for a reason
− ADCP position does influence results
• Numerical prediction (Tidal Bladed) close to measured
• Nose-mounted sensor:
− Promising but different hardware required
− Unable to replace IEC method for certified power curve (at present)
• Other IEC/TS 62600-200 assessment:
− Adjacent ADCP configuration
− Sensitivity to reference velocities and averaging periods

30. © ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on
that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without
liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.
Presentation title - 09/05/2016 – P 30
Conclusions & Ongoing work
This research was conducted as part of the Reliable Data
Acquisition Platform for Tidal (ReDAPT) project
commissioned and funded by the Energy Technologies
Institute (ETI).
The authors would also like to thank Greg Pittam at Alstom
Ocean Energy and Duncan Sutherland and Sam Harding
at the University of Edinburgh.

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