WEBINARUL Wind Energy Yield Method Update
Thursday September 10th, 2020 | 14:00 – 15:00 CEST
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PRESENTERS
MODERATOR
Thibaut LabondeBusiness Development Manager, Mediterranean
SPEAKERS
José VidalTechnical Director, Energy Advisory
Anaïs MadauleSenior Project Engineer, Energy Advisory
Kai MoennichSenior Engineering Leader, Energy Advisory
3
Site Screening &
Feasibility
Project Design /
Development
Pre-Construction
and FinancingConstruction OperationsComponent & System
ManufacturingResource / Energy
Assessment
Renewable Asset
Monitoring PlatformData products & Windnavigator
Openwind
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Digital Inspection Platform
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Platform
UL Digital Solutions
HOMER Energy
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Timeline of Key UL Backcast Studies
102 wind farms
• 97 in Germany
• 5 in France
190 wind farms
• 150 wind farms in Germany
• 39 in France
• 1 in Croatia
235 wind farms
• 160 in Germany*
• 62 in France
• 2 in Taiwan, 1 in Croatia
2008 2017
2008
*A portion of DEWI preconstruction estimates in Germany use operating data from nearby wind farms. This method was not
evaluated in the present study. Only estimates based on preconstruction meteorological measurements are considered.
11 wind farms
• All in US
2013 2017
2012
24 wind farms
• All in US
2017
UL -
DEWI
UL -
AWST
• Identify a set of projects for each method for which pre-
construction EYAs and post-construction operational
production data were available.
• Update the EYAs and operational estimates to current
methods as necessary.
• For a subset of projects with UL-DEWI pre-construction
EYAs, ran the standard UL-AWST method using the
same pre-construction data.
• Compare the results of both methods with the actual
production corrected to long-term conditions.
• Assess the factors that explain the observed deviations
for each method.
6
Backcast Procedure
Validation of the UL-AWST method
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8
UL-AWST Data Set Overview
MAP WITH PROJECTS
PER COUNTRY
1
1
2
39
Parameter Range Median
Operational Months per Plant 12 - 63 25.9
Plant Capacity (MW) 4.8 – 58.0 15.6
Number of Turbines 3 - 29 7
Turbine Nominal Power (MW) 0.8 – 3.3 2.1
Total Wind Farms: 43 (25 in common with UL-DEWI)
Plant-Years of Operation: 93
Enercon
Gamesa
Nordex
Senvion
Siemens
Vestas
1 1
6
2
7
8
2
4
5
3
1 1 1 1
0
1
2
3
4
5
6
7
8
9
75% 80% 85% 90% 95% 100% 105% 110% 115% 120% 125%
Nu
mb
er
of
pro
jec
ts
OP-EYA/EYA (<100% = Over-Optimistic)
Distribution histogram
Fitted normal distribution
Fitted normal centered on 100%
9
UL-AWST Results
Parameter PR*
Mean 101.3%
Median 99.7%
St Deviation 8.0%
*Production ratio (PR) is defined as the the post-
construction long-term estimate based on
operational data divided by the pre-construction
estimate of long-term energy yield. Values less
than 100% indicate the plant performs below
expectations.
• The average deviation of +1.3% indicates a tendency to slightly underestimate.
• The median deviation of -0.3% shows that half of the projects exceed the predicted P50.
• The difference between average and median deviations is caused by the skew in the
distribution.
• The main factors contributing to the observed deviation are:
➢ Shear adjustment (0.2%)
➢ Long-term adjustment (0.4%)
➢ Electrical losses (0.6%)
10
UL-AWST Results Analysis
Validation of the UL-DEWI method
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Enercon
Nordex
Senvion
Siemens
Vestas
EnerconFuhrländer
GE
Nordex
Senvion
Siemens
Vestas
12
UL-DEWI Data Set Overview
MAP WITH PROJECTS
PER COUNTRY
3
1
3
39
Parameter Range Median
Operational Months per Plant 9 - 68 30.6
Plant Capacity (MW) 4.6 – 72.6 18
Number of Turbines 2 - 29 8
Turbine Nominal Power (MW) 0.8 – 3.3 2.3
Total Wind Farms: 50 (25 in common with UL-AWST)
Plant-Years of Operation: 125
1
3
13
UL-DEWI Results
Parameter PR
Mean 93.8%
Median 94.0%
St Deviation 5.3%
0 0 0 0
2
6
11
6
10
6 6
0 1
2
0 0 0 0 0 00
2
4
6
8
10
12
75% 80% 85% 90% 95% 100% 105% 110% 115% 120% 125%
Nu
mb
er
of
pro
jec
ts
OP-EYA/EYA (<100% = Over-Optimistic)
Distribution histogram
Fitted normal distribution
Fitted normal centered on 100%
• The UL-DEWI method tends to overestimate plant production.
• The meteorological part of the pre-construction EYA method is unlikely to result in a
significant bias.
• Main driver of the observed bias are the loss assumptions.
• Changes need to be applied to the current method to reduce the observed bias.
14
UL-DEWI Results Analysis
Wind Energy Yield Method Update
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16
Timeline Method Harmonization
Phase I
2008October
1st
Phase II
Q1
2021
Full unified methodOne Method with:• UL-DEWI meteorological analysis
• UL-AWST wind flow and wake modeling
Guideline Hybrid Accredited
MEASNET: Evaluation of Site-Specific Wind
Conditions
IEC 61400-12-1: Wind Turbines - Part 12:
Power Performance Measurements of
Electricity Producing Wind Turbines
IEC 61400-1: Wind Turbines - Part 1: Design
Requirements
FGW TR6: Determination of Wind Potential
and Energy Yields
Application
On-shore projects in
Europe, Middle East
and North-Africa (excl. Iberia)
Projects that require
accreditation and TR6
compliance (mainly financed by German
financial institutions)
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Meteorological Input and ModelingChanges in current UL-DEWI Method on Oct. 1
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Meteorology
Characteristic UL-DEWI Hybrid / Accredited
Meteorological
input data
Wind Speed Frequency
Distribution (TAB file) at
measurement height
10-min time series at hub
height (converted to
frequency table by
Openwind)
Shear methodModeled with WAsP
(adjusted to measured)Measured
No change applied to the wind data analysis and long-term adjustment analysis.
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Modeling
Characteristic UL-DEWI Hybrid / Accredited
Wind Flow Model
WAsP supported by own
scripts (simple terrain) or
CFD (complex terrain)
SiteWind or
CFD (complex terrain)
Wake model Modified ParkOpenwind deep-array
wake model (DAWM)
Energy yield
calculationWAsP11 Openwind
SiteWind and Openwind widely used by UL-AWST
team over the world.
Loss AssumptionsCurrent UL-DEWI, Hybrid & Accredited Method
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• Wake Model changed from PARK (Jensen) to Eddy-Viscosity/Deep-
Array Model combination, which considers turbulence intensity and
effects in large wind farms
• On average higher farm losses, but at high Ti-sites also lower farm
losses possible
• Upwind Blocking Effect for projects > 50MW (including neighboring
WT), else 0%
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Losses – Turbine Interaction
Turbine Interaction UL-DEWI Hybrid Accredited
Wake Effects(internal, external, future)
Jensen EV & DAWM EV & DAWM
Upwind Blocking Effect 0%0%-3%
(calculated)0%
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Availability UL-DEWI Hybrid Accredited
Turbine Availability 3% 3% 3%
Availability of Collection &
Substation0% 0.2% 0%
Grid Availability 0% 0.3% 0%
Site Access 0% Calculated 0%
• Turbine Availability includes contractual and non-contractual availabilities
and planned maintenance assuming a full wrap maintenance contract exists.
• Substation availability: 2 events / year of each 8 hours
• Grid Availability: 4 events / year of 6 hours
• Site access expresses reduced availability for sites which may be hard to
reach during harsh weather conditions (offshore, icing, …). No or negligible
impact for standard projects expected.
Losses - Availability
• Electrical Efficiency considers normal European project characteristics.
Can be different if project characteristics differ.
• Electricity consumption of extreme weather package affects only
projects where WT are equipped with it. Other WF electricity consumption
assumed to be considered in financial model.
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Losses - Electrical
Electrical UL-DEWI Hybrid Accredited
Electrical Efficiency2% (default) or
calculated
2% (default) or
calculated
2% (default) or
calculated
Facility Parasitic
Consumption of Extreme
Weather Package
0% calculated 0%
Turbine Performance UL-DEWI Hybrid Accredited
Generic Power Curve Adjustment 0%Calculated 0%-2.1%
2.1% default
Calculated 0%-2.1%
2.1% default
Inclined Flow (Site Specific Power
Curve Adjustment)0% Calculated Calculated
High Wind Hysteresis Calculated Calculated Calculated
Sub-Optimal Performance 0% 1.5% 0%
• Generic Power Curve Adjustment considers identified difference in
AEP based on operational measured PC to theoretical PC.
• Inclined Flow: considers non-horizontal inflow conditions occurring in
orographic complex terrain.
• High Wind Hysteresis considers Cut-out and Re-Cut-in behavior at
high wind speeds.
• Sub-optimal Performance considers e.g. yaw misalignments, control
anemometer calibration, blade pitch inaccuracies or misalignments, and
other control setting issues.
Losses – Turbine Performance
Basic Concept
Following losses will be applied in case the WT power curve is
• Minimum Loss: 0%
• Maximum (and default) Loss: 2.1%
• Qualified: Direct Loss
-> Identified difference in AEP based on operational measured PC to theoretical PC
-> 6 tests, 3 sites having representative Ti conditions for project site (Ti Site +/- 5%)
• Not Qualified: Default and Maximum Possible Loss of 2.1%
• In Between: Hybrid Loss
-> Average of Direct Loss and 2.1%
-> Minimum of 4 tests at 2 sites
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Losses – Generic Power Curve Adjustment I
Family Concept
A Performance Family is a group of closely related turbine models of the same manufacturer.
• Often variants of the same base model
• Rotor Diameter as robust criterion for grouping a family
• All qualifying tests of WT types within a performance family are counted.
-> If family fulfills defined criteria, losses for „qualified“ or „hybrid“ will be applied
PCPMV (Power Curve Prediction Method Verification)
• PCPMV evaluates consistency of manufacturers method to predict their theoretical power curves
• Applies to verified Performance Families
• Consistency given -> Hybrid Power Curve Loss will be applied
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Losses – Generic Power Curve Adjustment II
• Icing is determined on identified icing periods in the measured data and
icing maps.
• Degradation considers expected dust and insect accumulation and precipitation.
• Wind Turbine Operational Temperature Range considers periods outside of
the OEM given operational temperature range of the WT. Considered to be
negligible for most European projects.
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Losses - Environmental
Environmental UL-DEWI Hybrid Accredited
Icing Calculated Calculated Calculated
Degradation 0.5% Calculated Calculated
Environmental Shutdown
(Operational WT temperature
range)
Calculated Calculated Calculated
• Curtailment losses will be calculated using OpenWind software, considering related
information is available.
• Curtailment losses can be combined, i.e. curtailments at same time periods caused by
different reasons are not counted double.
• Specific case that WT distance is smaller 3 rotor diameters and no curtailment info provided.
Hybrid Method will consider a curtailment for the affected sector.
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Losses - Curtailments
Curtailments UL-DEWI Hybrid Accredited
Load Related Calculated Calculated Calculated
Grid Related Calculated Calculated Calculated
Environmental (Bats&Birds,
Acoustic, Shadow Flicker, …)Calculated Calculated Calculated
Operational Strategies Calculated Calculated Calculated
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Losses - Impact of Changes (32 projects of the backcast study)
MethodAverage Loss Increase
Compared to UL-DEWI Losses
Remaining Gap to Average Yield
of Operational EYA
Hybrid Method 5.0% -1.3%
Accredited Method 3.0% -3.6%
Hybrid Accredited
Significant Reduction of P50 bias for Hybrid and Accredited Methods
Uncertainties
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• Identical uncertainty approach for hybrid and accredited services.
• Guidelines requirements still followed.
• Internal calculation procedures adjusted where necessary to also reflect method changes.
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Uncertainties
Results from
Backcast
Study
Overall uncertainties in wind speed are very similar
for UL-DEWI, UL-AWST and new planned method.
Overall uncertainties in energy are about 1% lower
for the new method compared to current UL-DEWI
method.
Very similar P75 and P90
Improved consistency of P-values
Observation backcast study: UL-DEWI P90
for pre-construction analysis slightly above the
ones from operational analysis.
Goal new method: improve the P90
assessment and unify methods between UL-
DEWI and UL-AWST.
Conclusion & Outlook
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• Effective from Oct. 1, 2020 for onshore Wind Energy Energy Yield
Assessments in Europe (except Iberia), Middle East & Northern Africa
• In EMENA, one hybrid method will be introduced :
➢ UL-DEWI meteorological analysis
➢ UL-AWST wind flow and wake modeling
• Main Differences concern UL-DEWI Losses
➢ Wake Losses due to Model change
➢ Generic Power Curve Loss
➢ Sub-Optimal (not accredited only)
Particularities for accredited services
• Relatively similar uncertainties
➢ Lower Power curve uncertainties
Phase 1 Updates corrects the observed bias on UL- DEWI method.
UL will bear the costs of existing EYA update (except project modifications)
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Summary of Phase 1
• Single UL method and toolset in
any part of the world
• Principal focus in:
➢ Meteorological analysis
➢ Wind flow modeling
• Compliance to Guideline
Requirements
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Harmonization Phase 2
Innovative
Consistent Flexible
Reliable
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Thank you !
QUESTIONS ?
Thibaut Labonde
+33 (0)4 27 18 10 20
José Vidal
+34 935 248 671
Anaïs Madaule
+33 (0)4 27 18 10 24
Kai Moennich
+49 44 17 79 37 102
Save the dates !
WEBINAR – UL Wind Energy Method Update – German
September 24th 2020 – 2pm
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WEBINAR – Step in the shoes of an Openwind & Windographer user – English
October 1st 2020 – 2pm
TRADESHOW – Colloque National Eolien - Paris
October 14-15th 2020
TRADESHOW – WindEnergy 2020 - Hamburg
December 1st-4th 2020