IEC TS 62600-300:2019

Marine energy - Wave, tidal and other water current converters - Part 300: Electricity producing river energy converters - Power performance assessment

IEC TS 62600-300:2019 provides:
· A systematic methodology for evaluating the power performance of river current energy converters (RECs) that produce electricity for utility scale and localized grids;
· A definition of river energy converter rated capacity and rated water speed;
· A methodology for the production of power curves for the river energy converters in consideration; and
· A framework for the reporting of results.
Exclusions from the scope of this document are as follows:
· RECs that provide forms of energy other than electrical energy unless the other form is an intermediary step that is converted into electricity by the river energy converter;
· Resource assessment, that will be addressed separately in the River Energy Resource Assessment Technical Specification;
· Scaling of any measured or derived results;
· Power quality issues;
· Any type of performance other than power and energy performance; and
· The combined effect of multiple river energy converter arrays.

General Information

• Status: Published
• Publication Date: 11-Sep-2019
• ICS: 27.140 - Hydraulic energy engineering
• Technical Committee: TC 114 - Marine energy - Wave, tidal and other water current converters
• Drafting Committee: ahG 12 - TC 114/ahG 12
• Current Stage: PPUB - Publication issued
• Start Date: 12-Sep-2019
• Completion Date: 16-Sep-2019

Overview

IEC TS 62600-300:2019 - "Marine energy - Wave, tidal and other water current converters - Part 300: Electricity producing river energy converters - Power performance assessment" - defines a systematic methodology to evaluate power performance of river current energy converters (RECs) that generate electricity for utility-scale or local grids. The technical specification establishes how to define rated capacity and rated water speed, produce certified power curves, and report results in a consistent, auditable way.

The standard focuses on demonstrated and tested electrical power performance and provides a framework for measurement, data processing and reporting. It explicitly excludes resource assessment (addressed separately), scaling of results, power quality, non-electrical energy outputs, non-power performance metrics, and combined-array interaction effects.

Key topics and technical requirements

• Definitions and operational parameters: rated capacity, rated water speed, capture area and operational states of RECs.
• Measurement requirements:
  • Electric power measurement and associated instrumentation.
  • River current measurement (profilers or other current meters) and data acquisition systems.
  • Calibration, averaging, filtering and data-exclusion procedures to ensure traceable measurements.
• Test types:
  • Demonstrated (in-situ) performance at river sites.
  • Tested performance in controlled environments (towing tanks, flumes, push/pull tests).
• Power curve production:
  • Use of binning methods (method of bins) to compute power curves from paired river speed and power data.
  • Procedures for interpolation, extrapolation and uncertainty quantification of the power curve.
• Derived metrics:
  • REC overall efficiency, mean vertical/horizontal shear profiles, RMS speed fluctuations, and directional statistics.
• Reporting framework:
  • Required content for REC reports, site reports, test equipment reports, measurement procedure documentation and uncertainty assumptions.

Applications and who uses this standard

IEC TS 62600-300:2019 is intended for:

• Device manufacturers validating claimed power output and rated capacity.
• Project developers and asset owners evaluating site suitability and expected energy yield.
• Test laboratories and research institutes conducting flume/towing tank and field trials.
• Certification bodies, investors and regulators requiring standardized, transparent performance data.
• System integrators sizing inverters, grid interfaces and electrical balance-of-plant based on verified power curves.

Practical benefits include consistent performance claims, improved comparability between REC designs, and robust datasets for financial modeling and permitting.

Related standards

• Other parts of the IEC TS 62600 series (marine/wave/tidal converters).
• The separate River Energy Resource Assessment Technical Specification (for resource characterization and not covered here).
• National and industry standards for electrical measurement and instrumentation may also apply.

Standards Content (Sample)

IEC TS 62600-300 ®
Edition 1.0 2019-09
TECHNICAL
SPECIFICATION
colour
inside
Marine energy – Wave, tidal and other water current converters –
Part 300: Electricity producing river energy converters – Power performance
assessment
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
IEC TS 62600-300 ®
Edition 1.0 2019-09
TECHNICAL
SPECIFICATION
colour
inside
Marine energy – Wave, tidal and other water current converters –

Part 300: Electricity producing river energy converters – Power performance

assessment
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.140 ISBN 978-2-8322-7293-0

– 2 – IEC TS 62600-300:2019 © IEC 2019
CONTENTS
CONTENTS . 2
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols, units and abbreviated terms . 9
4.1 Symbols and units. 9
4.2 Abbreviated terms . 11
5 Overview . 11
6 River current energy converter (REC) description . 12
6.1 General . 12
6.2 Operational parameters . 12
7 Demonstrated performance . 12
7.1 General . 12
7.2 Site and test conditions . 12
7.2.1 General . 12
7.2.2 Bathymetry . 13
7.2.3 Flow conditions . 13
7.2.4 REC test site constraints . 14
7.2.5 External constraints . 15
7.3 Test equipment . 15
7.3.1 Electric power measurement . 15
7.3.2 River current measurement . 16
7.3.3 Data acquisition . 17
7.4 Measurement procedures . 17
7.4.1 General . 17
7.4.2 Operational status . 17
7.4.3 Data collection . 18
7.4.4 Instrument calibration . 18
7.4.5 Data processing . 18
7.4.6 Averaging . 18
7.4.7 Test data properties . 19
7.4.8 Electric power measurement . 19
7.4.9 Incident resource measurement . 20
7.5 Demonstrated performance at a tidal influenced river site . 23
8 Tested performance . 23
8.1 General . 23
8.2 Towing tank tests . 25
8.2.1 General . 25
8.2.2 Test facility description . 25
8.2.3 Test equipment . 25
8.2.4 Measurement procedures . 25
8.3 Push and pull tests . 26
8.3.1 General . 26
8.3.2 Test setup and site description . 26
8.3.3 Test equipment . 26

8.3.4 Measurement procedures . 26
8.4 Flume tests . 27
8.4.1 General . 27
8.4.2 Test facility description . 27
8.4.3 Test equipment . 27
8.4.4 Measurement procedures . 28
9 Derived results . 29
9.1 General . 29
9.2 Water density . 29
9.3 Data processing . 29
9.3.1 Filtering . 29
9.3.2 Exclusion . 29
9.3.3 Correction . 29
9.4 Calculation of the power curve . 30
9.4.1 General description of the method of bins . 30
9.4.2 Detailed description of method of bins . 32
9.4.3 Interpolation . 36
9.4.4 Extrapolation . 36
9.4.5 Uncertainty calculation . 37
9.5 Mean river current speed shear profile . 37
9.5.1 General . 37
9.5.2 Current speed vertical shear profile . 37
9.5.3 Current speed horizontal shear profile . 38
9.6 RMS fluctuating river current speed . 39
9.7 Current direction at centroid of projected capture area . 40
9.8 Calculation of the REC overall efficiency . 41
10 Test reporting . 42
10.1 General . 42
10.2 REC report . 42
10.3 REC test site report . 43
10.4 Electrical grid and load report . 44
10.5 Test equipment report . 45
10.6 Measurement procedure report . 45
10.7 Tested performance report . 45
10.8 Presentation of measured data . 45
10.9 Presentation of the power curve . 47
10.10 Presentation of the REC overall efficiency . 49
10.11 Uncertainty assumptions . 51
10.12 Deviations from the procedure . 51
Annex A (normative) Categories of error . 52
Annex B (informative) Combining demonstrated and tested performance data to

create a single power curve . 53
Bibliography . 54

Figure 1 – Current profiler deployment position for placement A (plan view) . 21
Figure 2 – Current profiler deployment position for placements A and B (placement A:
profile view, placement B: plan view) . 22
This wide device has different lengths D and W. . 22
E
– 4 – IEC TS 62600-300:2019 © IEC 2019
Figure 3 – Current profiler deployment position for placement C (plan view) . 22
Figure 4 – Flume test equipment location . 28
Figure 5 – Summary of the power curve calculation using the method of bins . 31
Figure 6 – Vertical variation of river current speed across the projected capture area . 32
Figure 7 – Horizontal variation of river current speed across the projected capture area . 36
Figure 8 – Example circular histogram of river current direction . 44
Figure 9 – Example figure showing channel cross-sectional area occupied by the REC
on plane perpendicular to the principal flow direction (section view) . 44
Figure 10 – Example scatter plot of demonstrated performance data . 46
Figure 11 – Example plot of the mean river current speed vertical shear profile . 47
Figure 12 – Example presentation of the power curve . 48
Figure 13 – Example presentation of the power curve with uncertainty bars . 49
Figure 14 – Example presentation of demonstrated performance showing excluded

data points . 49
Figure 15 – Example presentation of the REC overall efficiency curve for
demonstrated and tested performance data . 50

Table 1 – Example presentation of the mean river current speed vertical shear data . 46
Table 2 – Example presentation of the RMS fluctuating river current speed at the
centroid of the projected capture area . 47
Table 3 – Example presentation of the power curve data . 48
Table 4 – Example presentation of demonstrated and tested overall efficiency . 50
Table A.1 – List of uncertainty parameters to be included in the uncertainty analysis . 52

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MARINE ENERGY – WAVE, TIDAL AND
OTHER WATER CURRENT CONVERTERS –

Part 300: Electricity producing river energy converters –
Power performance assessment
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a Technical
Specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical Specification are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62600-300, which is a Technical Specification, has been prepared by IEC technical
committee 114: Marine energy - Wave, tidal and other water current converters.

– 6 – IEC TS 62600-300:2019 © IEC 2019
The text of this Technical Specification is based on the following documents:
Draft TS Report on voting
114/300/RVDTS
114/284/DTS
114/300A/RVDTS
Full information on the voting for the approval of this Technical Specification can be found in
the report on voting indicated in the above table.
A list of all parts in the IEC 62600 series, published under the general title Marine energy -
Wave, tidal and other water current converters, can be found on the IEC website.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
MARINE ENERGY – WAVE, TIDAL AND
OTHER WATER CURRENT CONVERTERS –

Part 300: Electricity producing river energy converters –
Power performance assessment
1 Scope
This part of IEC 62600 provides:
• A systematic methodology for evaluating the power performance of river current energy
converters (RECs) that produce electricity for utility scale and localized grids;
• A definition of river energy converter rated capacity and rated water speed;
• A methodology for the production of power curves for the river energy converters in
consideration; and
• A framework for the reporting of results.
Exclusions from the scope of this document are as follows:
• RECs that provide forms of energy other than electrical energy unless the other form is an
intermediary step that is converted into electricity by the river energy converter;
• Resource assessment, that will be addressed separately in the River Energy Resource
Assessment Technical Specification;
• Scaling of any measured or derived results;
• Power quality issues;
• Any type of performance other than power and energy performance; and
• The combined effect of multiple river energy converter arrays.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60041, Field acceptance tests to determine the hydraulic performance of hydraulic
turbines, storage pumps and pump-turbines
IEC 60688:2012, Electrical measuring transducers for converting A.C. and D.C. electrical
quantities to analogue or digital signals
IEC 61400-12-1:2005, Wind turbines – Part 12-1: Power performance measurements of
electricity–producing wind turbines
IEC 61869-2, Instrument transformers – Part 2: Additional requirements for current
transformers
IEC 61869-3, Instrument transformers – Part 3: Additional requirements for inductive voltage
transformers
– 8 – IEC TS 62600-300:2019 © IEC 2019
IEC TS 62600-1:2011, Marine Energy – Wave, tidal and other water current converters –
Part 1: Terminology
IEC TS 62600-100:2012, Marine Energy – Wave, tidal and other water current converters –
Part 100: Electricity producing wave energy converters – Power performance assessment
IEC TS 62600-200:2013, Marine Energy – Wave, tidal and other water current converters –
Part 200: Electricity producing tidal energy converters – Power performance assessment
IEC TS 62600-301:2019, Marine Energy – Wave, tidal and other water current converters –
Part 301: River energy resource assessment
ISO IEC 17025:2017, General requirements for the competence of testing and calibration
laboratories
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement, (GUM:1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 62600-1 as well
as the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
blockage ratio
ratio of the flow-facing area of the moving and non-moving
parts, to the river cross-sectional area at the test site
3.2
demonstrated performance
portion of device operation for performance assessment that
occurs in a river that is representative of sites where the device will be deployed commercially
Note 1 to entry: Refer to Clause 7 for additional information.
Note 2 to entry: This contrasts with the term tested performance.
3.3
energy extraction plane
the plane that is perpendicular to the principal axis of energy
capture where device rotation or energy conversion nominally occurs
3.4
equivalent diameter
diameter of a circle with area equal to the device projected
capture area
3.5
principal axis of energy capture
axis parallel to the design orientation or heading of a River
Energy Converter passing through the centroid of the projected capture area

3.6
principal flow direction
primary orientation or heading of the river current
3.7
power-weighted speed
mean current speed derived with the weighted function of the
cube of the speed across the projected capture area
3.8
projected capture area
frontal area perpendicular to the principal flow direction of the
current energy converter components hydrodynamically utilized in energy conversion
3.9
rated water speed
lowest mean flow speed at which the river energy converter
rated capacity is delivered to its output terminals
3.10
tested performance
portion of device testing that is for the purpose of extending the
power curve beyond the range of velocities that is measured in the demonstrated
performance portion of the test
4 Symbols, units and abbreviated terms
4.1 Symbols and units
Symbol Description Unit
Projected capture area of the REC
A [m ]
Channel cross-sectional area at the test site at a particular volumetric flow rate
[m ]
A
Channel
Projected capture area of a ducted structure
[m ]
A
duct
Annual energy production
AEP
Area of kth current profiler bin across the projected capture area
[m ]
A
k
Cross-sectional area including all support structures
[m ]
A
Total
Total number of speed bins in the horizontal direction across the projected capture [-]
B
area normal to the principal axis of energy capture
Equivalent diameter [m]
D
E
Height of the capture area [m]
h
Index number of the current speed bin [-]
i
The set of data point indices, t, in speed bin i [-]
i , i , … i
1 2 N
Index number of the time instant when the measurement is performed [-]
j
Index number of the current profiler bin across the projected capture area [-]
k
Number of current speed data samples in the defined averaging period that produces [-]
L
U
data point t
Number of power data samples in the defined averaging period that produces data [-]
L
P
point t
M
Number of data points in speed bin i [-]
N
i
– 10 – IEC TS 62600-300:2019 © IEC 2019
Symbol Description Unit
Mean recorded REC active power in speed bin i [W]
�
P
i
Magnitude of the total instantaneous active electrical power from the REC [W]
P
j
� Mean REC active power after combining demonstrated data with scaled test data [W]
P
i
th
� Mean recorded REC active power output of the t data point [W]
P
t
Mean recorded REC reactive power in speed bin i [var]
�
Q
i
Magnitude of the total instantaneous reactive electrical power from the REC [var]
Q
j
th
Mean recorded REC reactive power output of the t data point [var]
�
Q
t
Radius of circular capture area [m]
R
Total number of current profiler bins normal to the principal axis of energy capture across the [-]
S
projected capture area
Index number of a data point [-]
t
Number of hours variation from UTC time [h]
T
Current speed of speed bin i [m/s]
U
i
� Mean current speed in speed bin i [m/s]
U
i
The power-weighted current speed in m/s averaged across the projected capture [m/s]
Û
j
area
Current speed flowing through current profiler bin k of the projected capture area, at [m/s]
U
j,k
time instant j
th
Power-weighted mean current speed of the t data point [m/s]
�
U
t
� Current speed data point in current profiler bin k over a given averaging period at a [m/s]
U
t,k
specific speed increment
th
Current speed flowing through the k current profiler bin of current profiler a, [m/s]
Ua
j,k
th
Current speed flowing through the k current profiler bin of current profiler b [m/s]
Ub
j,k
� Mean current speed flowing through current profiler bin k at the centroid of the [m/s]
Umean
t,k
projected capture area
������� RMS fluctuating current speed in current profiler bin k at the centroid of the projected [m/s]
Urms
i,k
capture area at speed bin i
RMS fluctuating current speed in current profiler bin k over the specified averaging
� [m/s]
Urms
t,k
period
Mean current speed in speed bin i at current profiler bin k [m/s]
���������
Ushear
i,k
Width of the capture area [m]
w
REC overall efficiency in current speed bin i [-]
η
system,i
speed bin increment [m/s]
ΔU
The test-data power scale factor [-]
γ
The river current direction of the hub height current profiler bin k [°]
θ
j,k
Mean river current direction of the hub height current profiler bin k over the defined [°]
�
θ
t,k
averaging period
-3
Fluid density
[kg m ]
ρ
4.2 Abbreviated terms
Abbreviation Description
AC Alternating Current
DC Direct Current
GPS Global Positioning System
IEC International Electrotechnical Commission
IHO International Hydrographic Organisation
ISO International Organisation for Standardization
REC River Energy Converter
RMS Root Mean Square
UTC Coordinated Universal Time

5 Overview
The primary objective of this document is to quantify the power output of a River Energy
Converter (REC) as a function of the current speed inflow in which it is designed to operate,
i.e. to quantify the device’s “power curve”. The accepted approach for accomplishing this is to
deploy a device at a representative deployment site, and simultaneously measure the inflow
speed to the device and the power output from it over a range of inflow speeds. This approach
works well for tidal energy converters and wind turbines (IEC 62600-200, IEC 61400-12),
because the inflow speed at representative deployment sites typically varies on a daily basis.
Sampling for several days, therefore, provides the range and repetition of inflow speeds that
is needed to populate an accurate power curve.
Testing devices in rivers, however, presents a challenge because river flow speed typically
varies on timescales of weeks to months. A device test, therefore, may need to last several
months before enough data is captured to populate an accurate power curve over the range of
speeds that the device is meant to operate. A test of this length may be untenable for many
REC device manufacturers, and may be unnecessary for the purpose of sufficiently
quantifying the power curve of many RECs.
To minimize the length and cost of REC power performance tests, this document combines
the approach of testing a device at a representative site – hereinafter termed “demonstrated
performance” – with the option to perform tested performance tests in a controlled scenario,
such as a “push” or “pull” test, in a flume, in a tow-tank, or in a tidal-influenced environment.
Demonstrated performance assessment is a requirement of this specification. Tested
performance assessment is optional for the REC manufacturer for the purpose of providing
additional power curve information beyond what is encountered during the demonstrated
performance portion of the test. Scaled models may not be used in either the tested
performance or demonstrated performance portion of the tests.
Extrapolating results beyond the range measured during either demonstrated or tested
performance is not permitted. Data from the tested performance and demonstrated
performance portions of the test may not be averaged together. A method for extending the
demonstrated power curve using tested performance data—only for the purpose of estimating
Annual Energy Production (AEP as described in IEC 62600-301)—is described in Annex B.
For all other purposes, results based on data from the demonstrated performance portion
shall be presented separately from results based on data from the tested performance portion.
For example, figures shall clearly identify and use distinct colours for the two data sets.
Discussion and conclusions regarding the REC performance should treat the demonstrated
performance data as the higher quality and more reliable dataset.

– 12 – IEC TS 62600-300:2019 © IEC 2019
6 River current energy converter (REC) description
6.1 General
A general description and diagram of the REC is required. Specifically, a description of the
system, including components, subsystems and a method of operation for the REC, as well as
a description of the expected operating envelope are required. Procedures for satisfying the
reporting requirements specified in 10.2 are described in 6.2.
6.2 Operational parameters
As well as a detailed description of the device system and operation method, given in 10.2,
the following parameters should be reported:
• REC rated capacity;
• Rated water speed;
• Equivalent diameter (D );
E
• Device width;
• Device height;
• Cut-in water current speed to begin power production;
• Low cut-out water current speed to end power production (if different from the cut-in water
current speed);
• Cut-out water current speed (maximum water current speed for REC operation);
• Rotational speed range or period for an oscillating device.
7 Demonstrated performance
7.1 General
This clause describes the methods for measuring REC performance on site or in a river that is
similar to the anticipated deployment locations. This demonstrated performance data should
be considered more representative of performance in other locations than the “tested
performance” data collected per Clause 8, and should be clearly emphasized in all reports as
such. 7.5 details methods for measuring REC performance in a tidal influenced river site such
as tidal channel or estuary.
7.2 Site and test conditions
7.2.1 General
The REC test site should be characterized in detail and reported prior to any assessment of
power performance. Specifically, the bathymetry and flow conditions should be clearly
identified. Guidance for satisfying the reporting requirements in 10.3 are described in this
section.
A test site should be a region where bathymetric changes (e.g. water depth and riverbank) are
small compared to the dimensions of the device. A test site should be on a straight section of
a river; locations that are up- or down-stream of large sandbars, sharp bends, or other
significant obstructions that alter the flow from a steady and uniform distribution should be
avoided. Whenever possible, the path of the thalweg should not change by more than 30° for
at least 3 river widths upstream of the test site. A test site should be a location where river
bathymetry and riverbank do not change significantly during the test. Bathymetric features
that do exist should be clearly documented.

7.2.2 Bathymetry
The bathymetry of the REC test site should be surveyed to ensure that it is free from
obstacles and topography that could affect the performance of the REC or the local quality of
the flow. It is recommended that the REC test site be surveyed 10 D upstream and
E
downstream of, and 5 DE on either side of, the REC location according to IHO Order 1a
hydrographic survey standard. A depth transect through the test site and across the entire
river should also be obtained to quantify the cross-sectional area of the river at the test site.
The riverbed and riverbank material (sand, clay, gravel, vegetation, etc.) should be
documented.
Any significant variation in the local bathymetry should be clearly identified and characterized
in detail. There should be no local bathymetric disturbances present that could lead to a
serious local variation in the quality and reliability of the incident resource, and thus, a
misrepresentation of the REC power performance.
Any known seasonal and inter-annual variability in bathymetry should be noted, and locations
where significant bathymetric changes occur should be avoided. For sites that are prone to
sedimentation or deposition (shifting bathymetry), the bathymetry survey should be completed
less than 30 days prior to the test. It is recommended that cross-stream bathymetry transects
through the test site be completed several (>3) times throughout the test period to confirm
that bathymetric changes during the test – relative to the full-sweep detailed bathymetric
survey – are minimal.
7.2.3 Flow conditions
7.2.3.1 General
It is necessary to characterize the general flow conditions of the REC test site to provide
context for the power performance assessment. Guidance is provided here for the
assessment of the following flow conditions: principal flow direction, lateral shear (the
variation of the mean stream-wise current speed in the cross-stream direction), and vertical
shear (the variation of the mean stream-wise current speed in the vertical direction).
It is important to take baseline measurements of the lateral and vertical shear at a test site
because significant shear can affect power performance measurements. The presence of the
river bottom creates vertical shear. Sites with large lateral shear should be avoided if possible
because meandering of this lateral shear across the energy-extraction plane during testing
will dramatically reduce the accuracy of device performance estimates. It is important to
measure principal flow direction because this indicates where the current profiler should be
placed relative to the REC during testing.
The flow conditions should be assessed as a set of at least 5 vertical profiles of current
speed. The vertical profile locations should be determined according to the following
guidelines:
• they should be evenly spaced in a line across the river that either:
• passes through the anticipated REC test site, or
• if the REC is deployed at the test site, is 2 to 5 D upstream of the REC location;
E
• they should span a distance of twice the REC width, or the entire channel width,
whichever is smaller;
• the spacing between profiles should be no more than twice the water depth;
• one of the profiles should be centred on the REC principal axis;
• at least one profile should be available on either side of the REC projected capture area.
The principal flow direction at the centroid of the projected capture area of the anticipated
REC deployment location should be calculated and provided. The lateral and vertical shear

– 14 – IEC TS 62600-300:2019 © IEC 2019
should be presented as cross-stream contour plots of the current speed profiles, line-plots of
those profiles, or as tabulated data of those profiles.
In order to resolve the mean-current speed (non-turbulent) estimates of these variables it is
important to average at least 10 min of current speed measurement data at each profile
location. The vertical profiles can be obtained from one of the following methods:
• from models corroborated by measurements;
• from current profiler transects.
7.2.3.2 Estimating flow conditions from models
Models corroborated by measurements may be used to estimate the flow conditions. For
example, a model from a resource assessment (IEC TS 62600-301) may be used to assess
and report flow conditions. The flow conditions should be taken from the model when the
model flow state is representative of the conditions expected during the test period (i.e. when
the river flow of the model is similar to the test period). If the model uses a time step of less
than 10 min several time steps should be averaged together to obtain a 10 min average. The
estimate of principal flow direction and lateral or vertical shear should be corroborated by
current profiler measurements taken during resource assessment, or during the test period.
7.2.3.3 Estimating flow conditions from current profiler transects
The flow conditions (5 vertical profiles of downstream current speed) may be measured using
a boat-mounted, downward-looking current profiler. These measurements should be made
when the flow rate of the river is similar to what is expected during the test period. The
locations of the profiles should be determined prior to performing transects according to the
guidelines in 7.2.3. The spacing between sampling levels should follow the same guidelines
as in 7.3.2. These profiles can be obtained by either:
• performing repeated transects across the river, and performing spatial binning until each
bin contains the required 10 min of data;
• holding station over each profile location for at least 10 min.
Spatial binning involves breaking transects into sections that are each nearest to the profile
location, and averaging together data from all transects that fall within a section. A current
profiler measurement may be included in a profile only if it is within a distance less than twice
the water depth of the profile location.
7.2.4 REC test site constraints
REC performance assessment may be affected by a variety of external influences that need to
be mitigated. The REC test site, therefore, should be representative of the final deployment
environment and bathymetry, with the following constraints:
• The REC test site should be free from any performance enhancing features (i.e. objects or
terrain that deflect flow to create local increases in the
...