SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
DETERMINATION OF WIND POTENTIAL AND ENERGY YIELD OF WIND TURBINES
PREPARED FOR: SOWI KOSOVO L.L.C
Ref. No.: UL-GER-WP17-12005195-02
SELAC SITE Mitrovica Kosovo
07 September 2018
CLASSIFICATION CLIENT'S DISCRETION
ISSUE 00
UL International GmbH 36-LO-F0853 – Issue 6.0 Kasinoplatz 3 | 26122 | Oldenburg www.ul.com/renewables
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 2/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Service Determination of the Wind Potential and Energy Yield of Wind Turbines
Site Selac SITE, Mitrovica, Kosovo
Offer No. 1101434524 Order No. 12005159 Standard/guideline -
Client SOWI Kosovo L.L.C Str. Mujo Ulqinaku No. 10 Prishtina, Kosovo 10000 Testing laboratory UL International GmbH Kasinoplatz 3 26122 Oldenburg Germany Commercial Contact UL International GmbH Kasinoplatz 3 26122 Oldenburg Germany
Remarks The test results documented in this report relate only to the items, site & configurations tested UL does not guarantee the calculated wind conditions or the calculated energy yield. This document may not be reproduced other than in full except with the permission of UL International GmbH.
DOCUMENT CONTRIBUTORS
AUTHOR(S) REVIEWER(S) APPROVED BY
Dr. Kai Mönnich Stefanie Peters Savas AdilogluM. Sc. Mechanical Engineer Dipl.-Phys. Dipl.-Met. Energy Services Energy Services Senior Engineering Leader Energy Services
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 3/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
NOTICE TO THIRD PARTIES This report was prepared by UL International GmbH (“UL”) and is based on information not within the control of UL. UL has assumed the information provided by others, both verbal and written, is complete and correct. While it is believed the information, data, and opinions contained herein will be reliable under the conditions and subject to the limitations set forth herein, UL does not guarantee the accuracy thereof. Use of this report or any information contained therein by any party other than the intended recipient or its affiliates, shall constitute a waiver and release by such third party of UL from and against all claims and liability, including, but not limited to, liability for special, incidental, indirect, or consequential damages in connection with such use. In addition, use of this report or any information contained herein by any party other than the intended recipient or its affiliates, shall constitute agreement by such third party to defend and indemnify UL from and against any claims and liability, including, but not limited to, liability for special, incidental, indirect, or consequential damages in connection with such use. To the fullest extent permitted by law, such waiver and release and indemnification shall apply notwithstanding the negligence, strict liability, fault, breach of warranty, or breach of contract of UL. The benefit of such releases, waivers, or limitations of liability shall extend to the related companies and subcontractors of any tier of UL, and the directors, officers, partners, employees, and agents of all released or indemnified parties.
KEY TO DOCUMENT CLASSIFICATION
STRICTLY CONFIDENTIAL For recipients only CONFIDENTIAL May be shared within client’s organization UL INTERNAL ONLY Not to be distributed outside UL CLIENT’S DISCRETION Distribution at the client’s discretion FOR PUBLIC RELEASE No restriction
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 4/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
RELATED DOCUMENTS
ISSUE TITLE STATUS
Site Related Wind Potential and Energy DEWI-GER-WP17-12005195-01.01 Draft of Preliminary Yield Assessment
DOCUMENT HISTORY
ISSUE DATE SUMMARY
UL-GER-WP17-12005195-02 2018-09-07 active issue 00
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 5/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
TABLE OF CONTENTS
1. Executive Summary ...... 7
2. Introduction ...... 9
3. Normative references ...... 10
4. Deviations to the Guideline ...... 11
5. Input Data and Project Information ...... 11 5.1 Topographical Data ...... 11 5.1.1 Site Inspection ...... 11 5.1.2 Description and Evaluation of Used Topographic Input ...... 13 5.2 Meteorological Input Data ...... 14 5.2.1 Description of On-site Wind Measurements ...... 14 5.2.2 Evaluation of Mast Measurement Data ...... 20 5.2.3 Evaluation of LIDAR Data ...... 28 5.2.4 Measured Wind Statistics ...... 30 5.2.5 Measured Wind Shear ...... 31 5.2.6 Correlation of the vertical Wind Profile ...... 34 5.2.7 Meteorological Long-term Data ...... 35 5.3 Data Filling and Long-Term Correlation ...... 41 5.3.1 Overview ...... 41 5.3.2 Filling of Data Gaps ...... 41 5.3.3 Comparison of Meteorological Long-term Data ...... 48 5.3.4 Long-term Correlation ...... 52 5.3.5 Wind Speed Statistics after Correlation ...... 53 5.4 Technical Data of the Wind Turbines ...... 57 5.5 Wind Farm Configuration ...... 59
6. Model Results ...... 60 6.1 Boundary Conditions for the Modeling - CFD ...... 60 6.1.1 Used Input Data and Applied Modifications ...... 60 6.1.2 Boundary Conditions for the Modelling - CFD ...... 60 6.2 Wind Conditions ...... 64 6.2.1 Results for the Reference Points ...... 64 6.2.2 Model Validation ...... 65 6.2.3 Results for the Wind Farm Area Selac ...... 67 6.3 Gross Energy Yield ...... 68 6.3.1 Detailed Results Config. 1: GE 3.8-137, Hub Height 110 m ...... 68
7. NET ENERGY YIELD ...... 70 7.1 Systematic Losses ...... 70
8. Quantitative Analysis of Uncertainties ...... 72 8.1 Wind Uncertainties ...... 72 8.2 Energy Uncertainties ...... 73
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 6/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
8.3 Exceedance Probabilities of Energy Yields (P-values) ...... 75
9. Further Derived Results ...... 76 9.1 Average Wind Speed Criterion ...... 76 9.2 Assessment of the Ambient Turbulence Intensity ...... 76
10. Comments ...... 80 10.1 Project Specific ...... 80
11. Appendix A - ADDITIONAL INFORMATION ...... 81 11.1 Photo-Documentation of the Site ...... 81 11.2 Documentation of the Measurements ...... 83 11.2.1 Photo-Documentation of the Mast and Sensors ...... 83 11.2.2 Photo-Documentation of the LIDAR ...... 87 11.2.3 Monthly Wind Statistics and Availabilities ...... 88 11.2.4 Monthly Availability Distribution ...... 89 11.2.5 Calibration Sheets of Used Anemometers...... 90
12. Model Results – WAsP ...... 96 12.1.1 Gross Energy Yield ...... 96 12.1.2 Detailed Results Config. 1:GE 3.8-137, Hub Height 110 m ...... 97 12.2 General Description of Energy Yield Assessment Procedure ...... 98 12.3 Description of the CFD Model ...... 101 12.3.1 Details of Post-processing ...... 101 12.4 Definitions of IEC-61400-1 ...... 102 12.4.1 Turbulence Intensity & Extreme Wind ...... 102 12.4.2 Topographical Complexity of the Site ...... 103 12.5 Used Software ...... 103 12.6 References ...... 103
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 7/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
1. EXECUTIVE SUMMARY
The determination of the Wind Potential and Energy Yield of Wind Turbines has been conducted for the Selac wind farm. The basis of the calculations are measured wind data from two masts at the Selac site. The data have been measured at a height of 94 m during a 21 month period and at 84 m during a 10 month period, and the measured average wind speed is 7.1 m/s at 94 m and 7.0 m/s at 84 m. A long term correlation has been performed with the on-site data and with data from the reanalysis data 850 hPa, grid point SW. LIDAR measurements were performed during a 4-months period. The measured wind profile were correlated with a stability parameter and included in this assessment. The calculated average long-term wind speed at the turbine positions varies between 6.5 m/s and 8.4 m/s at the hub height of 110 m. Energy yield evaluations have been carried out for one wind farm configuration as presented in Table 1.1, which is giving a summary of the results of the energy yield assessment using a CFD model.
Table 1.1: Summary of the calculation results for the Selac wind farm. (Gross wind farm AEP (free): No wakes losses have been considered.)
Wind Farm Configuration Configuration 1
Wind Turbine Type GE 3.8-137
Number of Wind Turbines 27
Nominal Power of the Wind Farm [MW] 103.4
Hub Height [m] 110
Average Hub Height Wind Speed [m/s] 7.5
Calculation Results
Free Gross AEP 364.9 GWh/a
Gross Farm AEP (including farm eff.) 344.9 GWh/a
Systematical Losses (including farm eff.) 12.9%
Systematical Efficiency (including farm eff.) 87.1%
Net wind farm AEP (including systematical losses) 317.9 GWh/a
Overall Uncertainty in Energy yield (long-term) 15.7%
Capacity Long-Term AEP [GWh/a] and Exceedance Probabilities AEP Factor
Net wind farm AEP P50 (exceedance probability 50%) 317.9 GWh/a 35.1%
Net wind farm AEP P75 (exceedance probability 75%) 284.1 GWh/a 31.3%
Net wind farm AEP P90 (exceedance probability 90%) 253.8 GWh/a 28.0%
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 8/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Within this report UL followed the MEASNET guideline “Evaluation of Site-Specific Wind Conditions” [4], the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10 [9] and the IEC61400-12-1 ed.2 [7]. Identified deviations to these guidelines are of severe importance; therefore it was not possible to create a report according to the guitelines.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 9/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
2. INTRODUCTION
The customer is planning the installation of a wind farm at the Selac site. The aim of the following calculation is to evaluate wind data and determine the expected annual average energy yield. Objectives of the calculation are: wind data evaluation and long-term correlation, assessment of wind speed statistics for the site, assessment of expected annual energy yields, estimation of the expected net energy output of the wind farm, including all relevant discounts (e.g. electrical losses, limited availability), detailed uncertainty assessment of calculated wind conditions & energy yields, presentation of corresponding exceedance levels (P-values). assessment of the ambient characteristic and representative turbulence intensity calculated at hub height at the reference points according to IEC 61400-1, ed. 2 [18] and ed. 3.1 [19]. The basis for calculating the annual energy yield is measured wind data at the site of the planned wind farm and additional meteorological data for the long-term correlation. This report (UL-GER-WP17-12005195-02.00) is the final version of the preliminary report DEWI-GER- WP17-12005195-01.01, which lost its validity with the publication of the final report.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 10/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
3. NORMATIVE REFERENCES
UL International GmbH is following the specifications of the following guidelines:
MEASNET1 Evaluation of Site-Specific Wind Conditions [4]
IEC61400-12-1 ed. 2, 03/2017 Wind energy generation systems –Part 12-1: Power performance measurements of electricity producing wind turbines
IEC61400-1: 02/1999 Wind turbine generator systems - Part 1: Safety Requirements, 2nd Ed. [18]
IEC61400-1: 04/2014 Consolidated Version, Wind turbine generator systems - Part 1: Safety Requirements, ed. 3.1 [19]
FGW e.V. (Fördergesellschaft Windenergie und Technical Guidelines for Wind Turbines, Part 6: andere Erneuerbare Energien) "Determination of wind potential and energy yield", revision 10 [9]
1 THE INTERNATIONAL MEASURING NETWORK OF WIND ENERGY INSTITUTES (MEASNET) IS A CO- OPERATION OF INSTITUTES WHICH ARE ENGAGED IN THE FIELD OF WIND ENERGY WITH THE GOAL TO ENSURE HIGH QUALITY MEASUREMENTS, UNIFORM INTERPRETATION OF STANDARDS AND RECOMMENDATIONS AS WELL AS INTERCHANGEABILITY OF RESULTS.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 11/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
4. DEVIATIONS TO THE GUIDELINE
The current work has been performed, according to the MEASNET2 guideline “Evaluation of Site- Specific Wind Conditions” [4] and the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10 [9]. Deviations from the criteria set out in the guidelines of section 3 are listed and commented in Table 4.1.Due to the low availability of the site measurement it was not possible to perform an energy yield assessment according to the guidelines.
Table 4.1: Deviations from the guidelines as given in section 2.[9]
Criteria Comments Section Availability of the anemometer at 94 m (Selac1) less Availability of the filtered data of the than 80 % primary sensor in combination with is 5.2 Availability of the anemometer at 84 m (Selac2) less backup sensor more than 80% than 80 % Availability of the data filled with MCP The availability of the measurements at the site is based on data at the site more than lower than 95 %. Remained data gaps were filled by 5.3 95% using of ConWx data.
Recalibration anemometers after 12 The anemometers were not recalibrated after a 12 months or the anemometers passed month period. It was not possible to perform the in-situ 5.2.2.2 in-situ test test for all used anemometer. This has been considered in the uncertainty analysis Wind turbines located in a Within this assessment some turbine positions are out "representativeness radius" of at least of the representative radius. one met mast: Additional due to the high complexity of the site the Flat Terrain 8.2 representative radius of the measurement mast might (homogenous roughness): 10 km be lower. Complex terrain
(homogenous roughness): 2 km Site Inspection A site inspection of the LIDAR was not performed.
5. INPUT DATA AND PROJECT INFORMATION
5.1 Topographical Data
5.1.1 Site Inspection The Selac wind farm site was inspected by Christian Kolthoff (UL International GmbH - DEWI) during 2016-10-25 - 2016-10-28 and during 2017-07-24 – 2017-08-09. The wind farm calculations are based on the following site description: The Selac wind farm site is located approx. 38 km north North West of Prestina and approx. 3.5 km North North East of the town Bajgora in the region of Mitrovica, Kosovo. The wind farm area is located in the southern part of the Kopaonik Mountains with an elevation of about 1600 m above sea level. Within the wind farm area the elevation varies between about 1330 m to 1720 m above sea level. The wind farm area and the surrounding land are predominantly covered by grass. To the southern part of wind farm area the amount of trees is increased.
2 THE INTERNATIONAL MEASURING NETWORK OF WIND ENERGY INSTITUTES (MEASNET) IS A CO- OPERATION OF INSTITUTES WHICH ARE ENGAGED IN THE FIELD OF WIND ENERGY WITH THE GOAL TO ENSURE HIGH QUALITY MEASUREMENTS, UNIFORM INTERPRETATION OF STANDARDS AND RECOMMENDATIONS AS WELL AS INTERCHANGEABILITY OF RESULTS.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 12/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The mountains extend from North to South. The lowest height is 500 m above sea level approx. 16 km to the west and around 450 m above sea level approx. 24 km to the east. Figure 5.1 shows the wind farm area and the surrounding area under investigation. The reference points, for which the detailed wind conditions have been calculated, are marked. Reference point 1 has the same position as the measurement mast Selac1 and reference point 2 has the same position as the measurement mast Selac2. An additional reference point has been chosen for the Lidar- Measurement position. A photo documentation of the site is included in the Appendix.
Figure 5.1: Map of site Selac with cartographic relief depiction. The positions of the measurement masts (reference point 1 and reference point 2) and the LIDAR position (reference point 3) are marked.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 13/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.1.2 Description and Evaluation of Used Topographic Input The orography applied in the calculation is provided by the client in the form of height contour lines. The orography map has been checked, validated and complemented by UL, where appropriate. Roughness information are taken from aerial photographs, complemented by impressions and notes from the site inspection. The following roughness lengths have been used by UL: General roughness length of the site: 0.05 m – 0.08° (grassland) and 0.2 m – 0.4 m (small bushes and trees) Roughness length of the small vegetation: 0.08 m.
Roughness length of mountain vegetation (small bushes and trees): 0.40 m. The designated roughness length was based on the present state of vegetation. It has been assumed that the vegetation during the lifetime of the wind farm remains the same. The forest that is in close vicinity to the west of the wind turbines has been considered only with roughness length values. No height displacement procedure was applied by UL. The measurement mast position is representative for the wind turbine positions regarding forest conditions, which makes this procedure unnecessary. For this report, all coordinates of wind energy converters, site centers and measuring masts are presented in UTM ETRS89, zone 34 coordinates. The customer has provided the coordinates for the wind turbines and the measurement mast. UL took the coordinates of the on-site mast by usage of a GPS-device (Global Positioning System) during site-inspection and verified the position with the given maps. Within the possible accuracy the coordinates of the client are confirmed by the UL-GPS- coordinates. The overall quality of the topographical database can be regarded as good.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 14/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.2 Meteorological Input Data
5.2.1 Description of On-site Wind Measurements
5.2.1.1 Main Properties of Site Wind Measurements Wind conditions at the Selac site have been measured at two meteorological measurement masts: Selac1 and Selac2. The mast installation has been performed by SME Consult and was supervised by UL. The measurements at the site are still ongoing. The wind data available to UL covers a period of 21 months since 2016-10-18 at mast Selac1 and a period of 10 months since 2017-09-01 at mast Selac2. For both measurement masts, a comprehensive documentation of the measurement mast configuration exists. [26] [27] The anemometers at the measurement masts Selac1 and Selac2 were replaced several times during the measurement period due to damage. At measurement mast Selac2 data of 5 months are missing from the beginning of 2017-12-05. Furthermore, a LIDAR measurement (Selac) was installed at the site with a distance of 1600 m to the north-north-east of the Selac1 mast by Notus Energy. At Lidar-Selac, wind data has been measured during a period of about 6 months since 2018-02-01. Due to a larger data gap from 2018-06-10 to 2018-07-25 finally only 4 month of data available. Table 5.1 shows main properties of the wind measurements. Figure 5.2 gives a graphical overview on the measurement periods and main data gaps of the different site measurements, including data gaps due to rejected invalid data (refer to section 5.3.1).
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 15/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.1: Main properties of the site measurements
Mast Selac1 Selac2 LIDAR Selac
Measurement period start 2016-10-28 2017-09-01 2018-02-01 stop / up to 2018-08-12 2018-07-09 2012-08-07 94 (v) 83.9 (v) 200,180,150,112, Measuring heights [m] 91.6 (v(2x), dir) 81.5 (v(2x), dir) 87,50,41,30 71.8 (v, dir) 61.4 (v, dir) V (ave,max,min,std,ver) 52.1 (v) 41.3 (v(2x)) dir 32 (v) 21.4 (v) State working working working UTM ETRS89, Zone 34 x-value 500759 501722 501488 y-value 4759195 4763331 4760460 Elevation [m] 1629 1725 1546 Availability* 91.4% 41.5% 72.5% Anemometer, Thies Clima Thies Clima/ R.M. Young ZephIR ZP 300 Thies Clima FC Adv. TFC advanced manufacturer/type and US 3D Sonic US 3D Sonic and RM Young Black Magic Thies Clima/ R.M. Young Wind vane, Thies Clima Thies First Class and RM ZephIR ZP 300 manufacturer/type Thies Compact Young Black Magic Data logger Amonit Meteo M40 Amonit Meteo M40 ZephIR ZP 300 Sampling rate 1 Hz 1 Hz
Time resolution of data 10 min. 10 min. 10 min. *System availability calculated respectively for the entire measurement periods before any data filtering.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 16/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.2: Graphical presentation of measurement periods and main data gaps.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 17/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.2.1.2 Data Integrity of Site Wind Measurements The traceability of the measurement campaign and the complete chain of processing steps are relevant for the uncertainty of the measured wind conditions [4]. To a certain extent, the data integrity can only be ensured if the measurement installation, operation and data evaluation is performed by a Measnet body or if the ISO/IEC 17025 is strictly applied by an accredited party. If the measurement was performed by a third party, additional uncertainty can arise due to missing protective measures to ensure data integrity. The data integrity is fully certified. No additional uncertainty value needs to be considered. Following the “Data Integrity” classification of MEASNET [4] as summarized in Table 5.2, the on-site measurements belong to class B.
Table 5.2: Short summary of MEASNET “Data Integrity” classification [4]
Class Data Integrity Description The MEASNET body undertakes or supervises the installation and maintenance of the measurement at the site. The monitoring and data evaluation is performed A Ensured by the MEASNET body. Hence the MEASNET body can ensure the integrity of the data.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 18/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.2: Short summary of MEASNET “Data Integrity” classification [4]
Class Data Integrity Description The measurement is performed according to a quality management system, which ensures the integrity and reproducibility of the measurement. A measurement accredited according to the ISO/IEC 17025 [8] meets these requirements if the ISO/IEC 17025 is being strictly applied. This means that no Ensured significant deviation from the standard shall occur, especially that the handling B and mounting of the sensors are carried out or supervised by the accredited party only, and that a calibration of the whole measurement system, traceable back to official standards, is performed. A remark shall be stated in the corresponding report that the measurement was not carried out completely by the MEASNET body. The data integrity is ensured to a high degree by protective measures. This can be achieved when a MEASNET body checks the logger configuration and sensor details during a site inspection, and has direct remote access to the data logger, to do at least random download and checks of the data. Protected It can also be realised by proving the authenticity and integrity of the complete C data chain by sufficient encryption and authentication measures, so that the data cannot be manipulated, in combination with an on-site check by the MEASNET body. A remark shall be stated in the corresponding report that the measurement installation and the data analysis was not carried out completely by the MEASNET body. The data are obtained by the MEASNET body in logger file format, preferably binary file format. The applied calibration factors are either included in the data Assessed by D files or can be demonstrated by detailed documentation. documentation A remark shall be stated in the corresponding report that the integrity of the measurement data can only be ensured to a small degree. The data are obtained by the MEASNET body as files with physical values only. To be also applied for all measurements for which it is not possible to verify whether the values are correct (e.g. if the calibration parameters have been Insecure applied correctly, poor documentation), the data integrity is insecure. This fact E shall be mentioned by the MEASNET body and considered for the uncertainty assessment. A remark shall be stated in the corresponding report, that the integrity of the measurement data is not ensured, protected or assessed by documentation.
5.2.1.3 Measurement Mast Set-up The measurement mast has been installed before the release of IEC61400-12-1 ed. 2 [7]. For this reason, the mast set-up is compared to the first edition of the IEC61400-12-1 [6]. The locations of the measuring masts are shown in Figure 5.1. A visual check of the masts has been performed during the site inspection and the condition of the measurement masts were good. The measurement mast Selac1 and Selac2 are shown in section 11.2. A detailed documentation of both measurement mast set-up were available and has been used for the assessment of the measurement quality. The installation of the measurement equipment at measurement mast Selac1 and Selac2 fulfills the criteria of the IEA [4] & IEC 61400-121 [6] recommendations. The highest anemometer has been installed in the top-mounted position with distances to the mast being sufficiently large. The influence of the measurement set-up on the highest measurement can be assumed as being negligible and the measurement can be regarded as being of high quality and complying with industry standards. The measurement height is within the recommended limits of at least 2/3 of the planed hub heights.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 19/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.2.1.4 Set-up of the LIDAR measurement During a LIDAR (LIDAR = Light Detection and Ranging) measurement campaign, the vertical wind profile was measured on the Selac wind farm. The measurement was performed with a ZephIR ZP 300LIDAR device. The Lidar-Selac measurement is located nearby the mast position Selac 1, at about 1600 m to the north-north east. Figure 5.1 shows the position of the LIDAR measurement and the met mast location. Table 5.1 shows the main data of these measurements. The system availability is given in section 5.2.3. The measurement volume is free of obstacles. During the site visit the LIDAR device has not been installed yet.
A comprehensive documentation of the LIDAR measurement set-up exists [29]. Figure A.1 in Appendix shows a photo of the LIDAR. The data have been logged with the following settings:
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 20/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.3: Basic parameters of the LIDAR measurement. Settings from the header of the raw data (choose format: _result.txt Format sta Format …) of the LIDAR measurement Lidar- Selac.
CSV Converter: v1.209 Filter: v1.040 File system version: V5 Unit: 737 Time Zone: UTC +0 hrs
5.2.1.5 Classification and Verification A verification according to the IEC 61400-12-1 ed.2 [7] was performed before the measurement the site Selac from 2017-11-27 06:30 to 2017-11-27 16:20 at the site of Pershore [29]
5.2.2 Evaluation of Mast Measurement Data The data have been measured by the client and provided to UL as raw data files. They have been measured as ten-minute-averages in m/s. Apart from wind speed and direction, the measurements comprise several other sensors like temperature, pressure and humidity.
5.2.2.1 Anemometer Calibration All the wind data of Selac1 and Selac2 have been logged as time-series with individual calibration values. At mast Selac1 and Selac2 the anemometers of type Thies First Class Adv. have been calibrated by Svend Ole Hansen and the Thies Clima 3D Sonic Sensor has been calibrated by Deutsche WindGuard according to ‘MEASNET’ standard3. The Young Propeller anemometer at Selac 2 has not been calibrated. At mast Selac1 all anemometer of type Thies First Class Adv. have been exchanged during the measurement period. All new anemometer have been calibrated by Svend Ole Hansen or Deutscher Kalibrierdienst according to ‘MEASNET’ standard. At mast Selac2 several sensors have been changed on 2018-05-04 due to damage.
3 The international Measuring Network of Wind Energy Institutes (MEASNET) is a co-operation of institutes which are engaged in the field of wind energy with the goal to ensure high quality measurements, uniform interpretation of standards and recommendations as well as interchangeability of results.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 21/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.4: Calibration values of the anemometers used for Selac1.
individual calibration (calibration reports/stored anemometer into the logger) measurement period type ID no. height a. g. l. calibration no slope offset Start Stop [-] [-] [m] [-] [m/s/Hz] [m/s] Thies Clima FC Adv. 09164041 94 16.02.3441 0.046540 0.228070 2016-10-28 2017-05-30 Thies Clima FC Adv. 02175801 94 17.02.00556 0.463700 0.225220 2017-05-30 2018-01-30 Thies Clima FC Adv. 06176813 94 171771 0.046052 0.260188 2018-01-30 2018-05-04 Thies Clima FC Adv. 06177019 94 17.02.01605 0.046390 0.218560 2018-05-04 Thies Clima US 3 D Sonic 10160055 91.6 1623802 0.983510 0.020800 2016-10-28 2018-01-30 Thies Clima US 3 D Sonic 03170070 91.6 1723124 0.986180 0.007800 2018-01-30 Thies Clima FC Adv. 09165674 91.6 16.02.03185 0.046480 0.227130 2016-10-28 2017-05-30 Thies Clima FC Adv. 09165679 91.6 16.02.0318 0.046560 0.205570 2017-05-30 2018-05-04 Thies Clima FC Adv. 12177110 91.6 18.02.00106 0.046430 0.216340 2018-05-04 2018-07-14 Thies Clima FC Adv. 06176811 91.6 171769 0.045990 0.261301 2018-07-14 Thies Clima FC Adv. 09164042 71.8 16.02.03442 0.046740 0.189540 2016-10-28 2017-05-30 Thies Clima FC Adv. 02175802 71.8 17.02.00557 0.046260 0.254100 2017-05-30 2018-05-04 Thies Clima FC Adv. 06177018 71.8 17.02.01606 0.046350 0.226820 2018-05-04 Thies Clima FC Adv. 09164043 52.1 16.02.03443 0.046560 0.214910 2016-10-28 2017-05-30 Thies Clima FC Adv. 02175803 52.1 17.02.00558 0.046310 0.252610 2017-05-30 2018-05-04 Thies Clima FC Adv. 06177017 52.1 17.02.01668 0.046350 0.232310 2018-05-04 Thies Clima FC Adv. 09164044 32 16.02.3444 0.046620 0.205330 2016-10-28 2017-08-02 Thies Clima FC Adv. 05176597 32 17.02.01391 0.046370 0.231630 2017-08-02 2018-05-04 Thies Clima FC Adv. 06177016 32 17.02.01608 0.046270 0.238080 2018-05-04
Table 5.5: Calibration values of the anemometers used for Selac2.
individual calibration (calibration reports/stored anemometer into the logger) measurement period type ID no. height a. g. l. calibration no slope offset Start Stop [-] [-] [m] [-] [m/s/Hz] [m/s] Thies Clima FC Adv. 02175804 83.9 17.02.00559 0.04633 0.24246 2017-09-01 2018-05-04 Thies Clima FC Adv. 09178527 83.9 17.02.02158 0.04642 0.22343 2018-05-04 Thies Clima US 3 D Sonic 05170005 81.5 1721407 0.98536 0.00070 2017-09-01 Thies Clima FC Adv. 02176300 81.5 17.02.00713 0.04627 0.23903 2017-09-01 2018-05-04 Thies Clima FC Adv. 12177109 81.5 18.02.00104 0.04629 0.22369 2018-05-04 Thies Clima FC Adv. 0516590 61.4 17.02.01398 0.04632 0.23887 2017-09-01 Thies Clima FC Adv. 0517588 41.3 17.02.01396 0.04632 0.21995 2017-09-01 2018-05-04 Thies Clima FC Adv. 09178524 41.3 17.02.02156 0.04645 0.20984 2018-05-04 RM Young 121447 41.3 - - - 2017-09-01 Thies Clima FC Adv. 05176591 21.4 17.02.01399 0.04640 0.21304 2017-09-01 2018-05-04 Thies Clima FC Adv. 05176595 21.4 17.02.01395 0.04641 0.21422 2018-05-04
5.2.2.2 In-Situ Test The operating performance of an anemometer can change during any period promptly or slightly by wearing or malfunction. In order to determine changes in the behavior of the anemometer the IEC 61400-12-1 [6],[7] recommend a post-calibration of the installed anemometers. If no post-calibration is available, an “in-situ” test shall be performed, which allows identifying gradual degradation of the calibration of the tested anemometer, and so the validity of the existing calibration for the entire measurement period. The method implies that a degradation at a similar rate for the anemometers used for the in-situ test cannot be identified [7].
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 22/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The mast-set-up allows the performance of an in-situ test. The test was performed according to recommendations in the IEC 61400-12-1 (annex K) [6], following the high standards for power curve measurements. The procedure determines the linear relationship of the tested anemometer with a reference anemometer during the beginning of the measurement campaign (period of maximum 8 weeks). The linear regression coefficients can finally be applied to the reference data at the end of the measurement campaign (period of maximum 8 weeks) and compared with the actual measured wind data from the tested anemometer. The square sum of the statistical deviation and the systematic deviation of the wind speed differences between actual measured wind speed from the tested anemometer and corrected wind speed of the reference anemometer is used as criteria. This value shall not exceed 0.1 m/s for each wind speed bin. If the deviation is in the range of ]0.1-0.2] m/s, an uncertainty of the magnitude of the deviation will be added to the wind measurement uncertainty. If the deviation is exceeding 0.2 m/s, and if possible with regards to the available measurement period, other periods are tested to check whether the gained deviation will decrease below 0.2 m/s. If this is not possible, the uncertainty will be increased. For very high deviation it might be possible that the data will be refused as input to the calculation. It should be noted that with this procedure a gradual degradation of the calibration of the tested anemometer cannot be identified if the reference anemometer degrades at a similar rate [6]. Selac1 In the present study the parameters in Table 5.6 were followed.
Table 5.6: Properties of the applied in-situ process and the valid sector determined according IEC 61400-12-1 (annex K) [6].
Wind Speed v@94 Wind Speed Reference v@92 Wind Direction dir@72 Temperature Temperature dir@72greater than 2°C Min Dir 180.00 Max Dir 220.00 Min Dir 2 (optional) 0.00 Max Dir 2 (optional) 40.00 2016-10-28 00:10:00 - Initial period 2016-12-23 00:10:00 2017-02-21 23:50:00 - Final period 2017-04-18 23:50:00
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 23/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.7: Results of in-situ test for the top anemometer during measurement period: 2016-10-28 – 2017-04-18.
Wind Speed Bin Root of Square Limit of 0.1 m/s Bin count Bin count >=3 [m/s] Sum [m/s] kept ] 6.0, 7.0] 17 True 0.01 True ] 7.0, 8.0] 6 True 0.02 True ] 8.0, 9.0] 12 True 0.01 True ] 9.0, 10.0] 4 True 0.01 True ] 10.0, 11.0] 10 True 0.02 True ] 11.0, 12.0] 9 True 0.01 True
The top anemometer has passed the 0.1 m/s criterion of the in-situ test for period 2016-10-28 – 2017-04-18, indicating that the calibration function did not change between beginning and end of measurement period, which is an indication of the high reliability of the anemometer readings. For the period 2017-05-04 – 2018-01-30 it was not possible to perform the in-situ test due to malfunction of the backup anemometer. Later periods were not checked, because they were not used directly for the calculations. Selac2 In the present study the parameters in Table 5.6 were followed.
Table 5.8: Properties of the applied in-situ process and the valid sector determined according IEC 61400-12-1 (annex K) [6].
Wind Speed v@84 Wind Speed Reference v@82 Wind Direction dir@62 Temperature Temperature T@80greater than 2°C Min Dir 180.00 Max Dir 220.00 Min Dir 2 (optional) 0.00 Max Dir 2 (optional) 40.00 2017-09-01 00:10:00 - Initial period 2017-10-13 00:10:00 2017-10-23 21:20:00 - Final period 2017-12-04 21:20:00
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 24/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.9: Results of in-situ test for the top anemometer during measurement period: 2017-09-01 – 2017-12-04
Wind Speed Bin Root of Square Limit of 0.1 m/s Bin count Bin count >=3 [m/s] Sum [m/s] kept ] 6.0, 7.0] 24 True 0.05 True ] 7.0, 8.0] 31 True 0.02 True ] 8.0, 9.0] 28 True 0.04 True ] 9.0, 10.0] 22 True 0.02 True ] 10.0, 11.0] 22 True 0.04 True ] 11.0, 12.0] 14 True 0.04 True
The top anemometer has passed the 0.1 m/s criterion of the in-situ test for the period 2017-09-01 – 2017-12-04, indicating that the calibration function did not change between beginning and end of measurement period, which is an indication of the high reliability of the anemometer readings. For the period 2018-05-04 – 2018-07-09 it was not possible to perform the in-situ test due to malfunction of the backup anemometer.
5.2.2.3 Data Processing All records in the given time-series, which have not been recorded using the individual calibration values, have been re-calibrated to the individual calibration values by UL. A consistent time-series has been produced with a temporal resolution of 10 min-means in the unit m/s. Afterwards, the data have been screened manually, and data, which have been flagged as faulty, have been sorted out. The top anemometer at Selac 1 shows several larger data gaps for the following periods 2017-01-04 – 2017-01-21, 2017-4-18 to 2017-05-30, 2017-08-17 – 2017-10-10, 2018-02-07 – 2018-02-17, 2018-02- 19 – 2018-03-02 and 2018-03-02 – 2018-05-04. The data for these periods were cut out. Additionaly, lots of icing events occurred during the measurement period. The top anemometer at Selac 2 shows two larger data gaps for the following periods 2017-09-18 – 2017-10-01 and 2017-12-01 – 2018-05-04. The data for these periods were cut out. Additionaly, lots of icing events occurred during the measurement period. The magnetic declination at the site of approx. 4.5° East has been considered for the wind direction measurement, and within this report all directions refer to geographic north. For the wind vanes at mast Selac1 no direction offset were stored in the logger. Therefore the direction offsets of +290° for wind vane at 92 m and +289° for wind vane at 72 m were applied to the wind direction data. As there were no direction offsets considered at mast Selac2 before also, a direction offset of +290° for wind vane at 82 m and 41 m and an offset of +291° for the wind vane at 61 m were applied to the wind direction data. A detailed measurement report has been available.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 25/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Due to the mentioned restrictions and data filtering, the top anemometer data shows a data availability of 58.5% for Selac 1 for the measurement period 2016-10-28 – 2018-08-12. The MEASNET criterion of 12 complete months with a sensor data availability of minimum 90% is therefore not fulfilled [4]. For the final used period 2016-11-01 – 2017-10-31 for Selac 1 the data availability is 58.9 % Due to the mentioned restrictions and data filtering, the top anemometer data shows a data availability of 39.6% for Selac 2 for the measurement period 2017-09-01 – 2018-07-09. The MEASNET criterion of 12 complete months with a sensor data availability of minimum 90% is therefore not fulfilled [4]. For Selac 1 some of the data gaps have been filled by correlation with data of the reference anemometer at 92 m (Sonic) and the anemometer at 92 m and 32 m as well as the top anemometer at mast Selac 2 as described in section 5.3.2., leading to a data availability of 88.1% for period 2016-11-01 – 2017-10-31. The MEASNET and TR6 minimum criterion of 95% available filtered and filled data is therefore not fulfilled [4] ,[9]. For Selac 2 some of the data gaps have been filled by correlation with data of the filled top anemometer of Selac 1 as described in section 5.3.2., leading to a data availability of 73.3% for period 2016-11-01 – 2017-10-31. The MEASNET and TR6 minimum criterion of 95% available filtered and filled data is therefore not fulfilled [4] ,[9]. Afterwards the data gaps have been filled by correlation with the ConWX reanalysis data.
5.2.2.4 Correction of the Lightning Catcher Effects on Measurement Data The top anemometers at the Selac1 and Selac2 measurement masts are affected by shading effects of the lightning catcher. This corresponds to an increased uncertainty of the measurement data. For wind energy purposes unaffected data are preferred. In order to reduce the shading effect a time series correction has been performed. Selac1 To evaluate possible speed-up or shading effects of the lightning catcher on the anemometers, the relative wind speed ((94 m/92 m) has been analysed over direction (top graph in Figure 5.3), in which you clearly see the effect of the lightning catcher at the expected directions. The shading effect of the lightning catcher on the top anemometer has been corrected using the relation of the top anemometer and the reference anemometer wind speed measurements. For applying this correction, UL assumed the reference anemometer measuring the correct wind speed in the correction sector. The shading correction function for the 94 m -data has been calculated for the wind speeds above 3 m/s in the directional range between 165° and 190° (bottom graph in Figure 5.3).
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 26/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.3: Relative wind speeds (v@94m/v@92m) measured at the mast Selac1 depending on the wind direction.Top: without shading effect correction Bottom: correction of the shading effect for the top anemometer (94 m)
Selac2 To evaluate possible speed-up or shading effects of the lightning catcher and/or mast on the anemometers, the relative wind speed ((84 m/82 m) has been analysed over direction (top graph in Figure 5.3), in which you clearly see the effect of the lightning catcher at the expected directions. The shading effect of the lightning catcher on the top anemometer has been corrected using the relation of the top anemometer and the reference anemometer wind speed measurements. For applying this correction, UL assumed the reference anemometer measuring the correct wind speed in the correction sector.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 27/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The shading correction function for the84 m -data has been calculated for the wind speeds above 3 m/s in the directional range between 160° and 180° (bottom graph in Figure 5.3).
Figure 5.4: Relative wind speeds (v@84m/v@82m) measured at the mast Selac1 depending on the wind direction. Top: without shading effect correction Bottom: correction of the shading effect for the top anemometer 84 m)
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 28/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.2.3 Evaluation of LIDAR Data The data has been measured by Notus Energy and provided to UL as raw data of the remote sensing instrument with a time resolution of 10 minutes as csv-files. UL converted the data to time series for each height. Data sets have been filtered by UL with standard filtering methods. The data reported as inconsistent (NaN and wind direction values outside the range [0-360]°) has been filtered out. No further filtering has been applied by UL. Table 5.10 shows the data availability at each height after filtering. The availability decreases with the increasing height. At the height of the planned hub height the availability is 50.5 %. The measurements have a significantly lower availability than MEASNET [4] and TR6 [9] recommends. It cannot be used as a basis for a reliable site assessment.
Table 5.10: Availability of the LIDAR measurements at the Selac site during the period 2018-01-31 - 2018-08-07 after filtering of the data.
Measurement height Height above ground Availability [%] [m] [m] 27 30 64.6 38 41 60.7 47 50 58.3 84 87 52.3 109 112 50.5 147 150 49.2 177 180 48.4 197 200 48.1
Figure 5.5 shows the wind speed and wind direction distribution of the data measured at heights 109 m during the LIDAR campaign. The vertical wind shear exponent α has been calculated according to IEC 61400-1, ed. 3.1 [19] from concurrent measured data from the height levels between 84 m and 108 m. For the regarded months α is shown in Table 5.11.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 29/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.11: Wind shear exponent α LIDAR measurements at the site Selac. The measurement heights 84 m – 109 m were used to assess α.
Monthly variation Month Alpha Feb 0.096 Mar 0.1569 Apr 0.0921 May 0.0798 Jun 0.1111 Jul 0.1113 Aug 0.0205
The vertical wind shear at the Selac site is relative low.
Figure 5.5: Measured wind direction and wind speed distribution for LIDAR at the Selac site, valid for the height of 109 m. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.) N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 30/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.2.4 Measured Wind Statistics The wind data measured at the Selac1 mast have been used as the main input for the energy yield calculation. The measured wind direction and wind speed distributions for the Selac1 mast for the 94 m measuring height are shown in Figure 5.6 and for Selac2 mast for the 84 m measurement height are shown in Figure 5.7. The plots of the wind speed distribution show the parameters of the overall Weibull distribution (scale factor A, shape factor k) as well. The prevailing wind direction is North-West and South-West. The average wind speed during the period 2016-10-28 – 2018-08-12 is 7.1 m/s for Selac 1. For Selac 2 the prevailing wind direction is West and North-East and the average wind speed during the period 2017-09-01 – 2018-07-09 is 7.0 m/s
Figure 5.6: Measured wind direction and wind speed distribution for Selac 1 at the Selac site, valid for the height of the top anemometer. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 31/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.7: Measured wind direction and wind speed distribution for Selac 2 at the Selac site, valid for the height of the top anemometer. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.) N
W E
S
5.2.5 Measured Wind Shear The vertical wind shear exponent α has been calculated based on the measurements of Selac1 between the height levels of 52 m and 94 m. The wind shear is defined according to IEC 61400-1, ed. 3.1 [19] using the following formula for the vertical variation of wind speed:
h (1) v(h) vhub hhub
where vhub is the wind speed at hub height and α is the wind shear exponent. For the determination of the wind shear exponent α from the measured data at the Selac1and Selac2, the wind speed measurements at the height specified in Table 5.12 are considered. The lower measurements at the mast was not used for the assessment of the wind shear in order to minimize disturbances from the roughness. Effects due to the shading of the mast and lightning catcher have been filtered in the data set (Table 5.12). The vertical wind shear at the Selac site is relatively low. For Selac1 the measurement period of 2016-10-28 – 2017-11-19 were used in order to have a 1 year period to avoid seasonal effects. Since the measurement period at Selac2 is shorter than 1 year it will not shown here.
Table 5.12: Overview of the measured wind profiles at the Selac. Mast Measured Period Wind Direction Heights Measured Range (filtered) considered Wind Shear [deg] [m] [-] 2016-10-28 – Selac1 95-125 94, 72 and 52 0.11 2017-11-19
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 32/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The wind shear exponent α was determined for each 10 minute time step by adapting α in equation (1) such that the wind shear as described by equation (1) fits the measured data. Table 5.13 and Figure 5.8 show the measured average wind shear per wind direction sector.
Table 5.13: Measured average wind shear per wind direction sector for the Selac site.
Sector Heights Mean wind shear considered Selac1 [m] [-] 0° 94 m, 52 m 0.18 30° 94 m, 52 m 0.03 60° 94 m, 52 m -0.01 90° 94 m, 52 m -0.01 120° 94 m, 52 m 0.17 150° 94 m, 52 m 0.07 180° 94 m, 52 m 0.05 210° 94 m, 52 m 0.12 240° 94 m, 52 m 0.04 270° 94 m, 52 m 0.10 300° 94 m, 52 m 0.12 330° 94 m, 52 m 0.17
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 33/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.8: Directional variation of the vertical wind shear at the Selac1 mast at Selac.
Wind shear exponent variation according to wind direction [-15,15[ 0.3 [315,345[ 0.25 [15,45[ 0.2 [285,315[ 0.15 [45,75[ 0.1 0.05 0 [255,285[ -0.05 [75,105[
[225,255[ [105,135[
[195,225[ [135,165[ [165,195[
For the measurement period 2016-10-28 – 2017-11-19, the regarded monthly wind shear is shown in Table 5.14.
Table 5.14: Monthly wind shear exponent at the site Selac.
Month Heights to determine Mean wind shear wind shear Selac1 [m] [-] January 94 m, 52 m 0.05 February 94 m, 52 m 0.25 March 94 m, 52 m 0.35 April 94 m, 52 m 0.27 May 94 m, 52 m 0.20 June 94 m, 52 m 0.08 July 94 m, 52 m 0.04 August 94 m, 52 m 0.02 September 94 m, 52 m - October 94 m, 52 m 0.06 November 94 m, 52 m 0.09 December 94 m, 52 m 0.15
Figure 5.9 shows the intraday variation of the vertical wind shear exponent α during the period 2006- 10-28 – 2017-11-18.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 34/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.9: Intraday variation of the vertical wind shear at the site Selac.
Daily variation of the wind shear exponent 0.3
0.25
]
- [
α 0.2
0.15
0.1 Wind shear exponent
0.05
0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Time [-]
5.2.6 Correlation of the vertical Wind Profile In general, there are strong daily and seasonal variations of the vertical wind profile. Therefore, the measured wind profile of the short-term measurement campaign cannot be considered representative of the long-term conditions. The seasonal influence on the measured vertical wind profile can be considered and corrected only if the data basis is large enough and covers a wide range of wind speed, direction and shear conditions. Therefore, the available data was first tested with respect to its representativeness of the long-term conditions. In a second step, the wind profile data was correlated to a stability parameter in order to assess and correct the seasonal influences. The data measured at 84 m and 110 m with LIDAR have been used for the evaluation in the following analysis. To consider seasonal variations, the following procedure has been used: 1. For each 10min time step of the LIDAR measurement, the cosine of the sun’s zenith angle has been calculated using the geographic position of the remote sensing device. 2. The ratio of the mean measured wind speeds between the measurement heights 102 m and 142 m has been calculated and used to estimate the vertical wind profile. 3. For each class of the cosine of the zenith angle (from -1 to 1 in steps of 0.05), the average wind speed ratio has been calculated. In addition, the relative frequency of each class of zenith angle has been calculated. 4. The expected wind speed ratio for a full year has been assessed by calculating a weighted average of the wind shear using relative frequencies of the different zenith angles bins referring
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 35/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
to a full year. This procedure has been performed on a direction dependent basis with a sector width of 30°. Figure 5.10 shows the measured wind speed ratio 112 m/87 m with LIDAR versus cosine zenith angle.
Figure 5.10: Measured wind speed ratio 109 m /84 m with LIDAR versus cosine zenith angle.
Wind speed ratio versus solar altitude 1.7 4000 Mean Ratio Bin Count Short-term Period 3500 1.5 Bin Count 1-year Period 3000
1.3 2500
1.1 2000 Bin Count Bin 1500 0.9
1000 Wind Speed Ratio v(109m)/v(84m) Ratio Speed Wind 0.7 500
0.5 0 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 Cosine of Solar Zenith Angle [-]
The correlation of the wind profile results in the measured vertical wind profile of the short-term LIDAR campaign being representative for long-term conditions. No seasonal correction has to be applied on the measured wind profile. The measured wind profile has been applied for the vertical extrapolation from the height of 84 m to the hub height of 110 m.
Table 5.15: Wind speed ratio and wind shear exponent α during the LIDAR campaign and during a full year-period.
v@109m/v@84m Wind Shear α Short-term Period 1.030 0.11 1-year Period 1.032 0.12
5.2.7 Meteorological Long-term Data The short-term measurement data are correlated with different long-term meteorological data sources to find the most reliable data source for filling of data gaps as well as for the long-term correction of the measured wind statistics. A long-term correction has to be performed in order to decrease the influences of year-to-year wind variations on the short-term wind statistics.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 36/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The main characteristics of the different used long-term data sets are presented below. An extensive comparison of all considered meteorological long-term data sets is presented in section 5.3.3.
5.2.7.1 Reanalysis Wind Data Data provided from the NCAR/NCEP Global Reanalysis Project I [16] at 850 hPa, 925 hPa, surface wind data and wind data at 10 m height above ground for all of the surrounding four grid points and the interpolated site value have been additionally incorporated into the long-term analysis. The NCEP/NCAR Reanalysis Projects use a fixed and consistent global data assimilation and filtering system and a data base as complete as possible. The advantages of using these data are its possible independence from local influences like obstacles or vegetation, the filtering of the data and its consistent availability.
Table 5.16: Overview of the used Reanalysis wind data.
Data source NCAR/NCEP Reanalysis Data period investigated 1990-01-01 – 2018-07-31 Data period used 2003-07-01 – 2018-06-30 Time resolution 6 h Grid resolution 2.5x2.5 Degree, irregular for 10 m height
As the geostrophic wind is in general the driving force for the surface winds, the geostrophic wind data can be used directly for long-term correlation and extrapolation of the local wind conditions if the correlation to the site data is sufficient. Even in the case of a weak correlation of the monthly mean values, the Reanalysis wind data can be used to check the plausibility of the long-term trend of meteorological surface wind data and to estimate the order of year-to-year wind variations. Figure 5.11 shows the wind distribution of the used grid point SW (42.5° N, 20° E).
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 37/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.11: Wind direction and wind speed distribution of the used grid point 42.5° N, 20° E) of the NCAR/NCEP Reanalysis wind data. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
5.2.7.2 MERRA-2 Reanalysis Data Data from the GMAO4 MERRA-25 reanalysis project [21] have been considered for long-term correction. The GMAO MERRA-2 data product is based on the GEOS-5 Data Assimilation System with the integrated Atmospheric Data Assimilation System (ADAS, version 5.12.4), conducted at the NASA Center for Climate Simulation (NCCS). These systems have been optimized in the recent years, so that the MERRA-2 reanalysis product replaces the old MERRA reanalysis product. Input of the used MERRA-2 data are global observations collected over the so called “satellite era” (from 1980 to the present) and assimilated into a global circulation model (GEOS-5 GCM). Similarly to other reanalysis projects, the analysis is designed to be as consistent as possible over time and it uses a fixed assimilation system. This is a contrast with weather-focused analysis where the assimilation system may vary over time as changes to the model and the analysis are implemented to improve weather forecasts. The MERRA-2 reanalysis products include several variables available at different spatial and temporal resolution. The dataset used in the present assessment were hourly time series of wind speed at a resolution equal to ⅔° longitude and ½° latitude for the 50m diagnostic level. The time series have been extracted for all the four grid points surrounding the site. An additional time series has been produced by UL by bilinear interpolation to the site position.
4 Global Modeling and Assimilation Office of the NASA Center for Climate Simulation 5 The Modern Era Retrospective-analysis for Research and Applications
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 38/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.17: Overview of the used MERRA2 wind data.
Data source GMAO MERRA-2 Reanalysis Data period available 1980-01-01 – 2018-06-30 Time resolution 1 h Grid resolution ⅔° longitude and ½° latitude
5.2.7.3 ECMWF ERA-Interim Reanalysis Data Data from the ECMWF ERA-interim reanalysis project [22] have been considered for long-term correction. The ERA-Interim reanalysis data product is based on the global circulation model and a 4D- VAR data assimilation system. The input of the used ERA-Interim data is global observations collected over the so called “satellite era” (from 1979 to the present) and assimilated into a coupled atmospheric – ocean-wave model: the ECMWF Integrated Forecast System (IFS). Similarly to other reanalysis projects, the analysis is designed to be as consistent as possible over time and it uses a fixed assimilation system. The ERA-Interim reanalysis products include several variables available at different spatial and temporal resolution. The dataset used in the present assessment were 6 hourly time series of wind speed at a resolution equal to 0.8° longitude and 0.8° latitude for the heights 68 m and 118 m. The time series have been extracted for all the four grid points surrounding the site. An additional time series have been produced by UL by bilinear interpolation to the site position.
Table 5.18: Overview of the used Reanalysis wind data.
Data source ECMWF ERA-Interim Reanalysis Data period available 1979-01-01 – 2018-05-31 Time resolution 6 h Grid resolution 0.8° longitude and 0.8° latitude
5.2.7.4 EMD ConWX Mesoscale Data Data from the EMD ConWX Mesoscale project [24] have been additionally incorporated into the long- term analysis. The data are modeled by EMD and based on ERA-Interim reanalysis data. The input of the used ERA-Interim data is global observations collected over the so called “satellite era” (from 1979 to the present) and assimilated into a coupled atmospheric – ocean-wave model: the ECMWF Integrated Forecast System (IFS). Similarly to other reanalysis projects, the analysis is designed to be as consistent as possible over time and it uses a fixed assimilation system. An advantage of this dataset lies in the mesoscale physical modeling step, which allows it to solve atmospheric phenomena with finer spatial and temporal resolutions. As a consequence, the mesoscale modeling can describe the wind distributions on site, case by case, more accurately than the pure meteorological input datasets. The EMD ConWX Mesoscale Data includes several variables available at different spatial and temporal resolution. The dataset used in the present assessment were hourly time series of wind speed at a resolution equal to 0.03° longitude and 0.03° latitude for 6 different surface levels (25 m, 50 m, 75 m,
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 39/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
100 m, 150 m, 200 m, above ground). The time series have been exported from WindPRO for the requested location of the site. .
Table 5.19: Overview of the used EMD ConWX wind data.
Data source EMD ConWX Mesoscale dataset Data period available 1993-01-01 – 2018-05-31 Data period used for Selac 1 2016-11-01 – 2017-10-31 Data period used for Selac 2 2017-07-01 – 2018-05-31 Time resolution 1 h Grid resolution 0.03°
Figure 5.12 shows the wind distribution of the grid point used for Selac 1 (42.98° N, 21.02° E), at the height of 200 m. Figure 5.12: Wind direction and wind speed distribution of the used grid point (42.98° N, 21.02° E) of the used EMD ConWx Mesoscale data. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 40/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.13 shows the wind distribution of the grid point used for Selac 2 (43.01° N, 21.02° E) at the height of 75 m.
Figure 5.13: Wind direction and wind speed distribution of the used grid point (42.98° N, 21.02° E) of the used EMD ConWx Mesoscale data. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 41/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.3 Data Filling and Long-Term Correlation
5.3.1 Overview The measurements Selac1 and Selac2 have some data gaps due to filtering of implausible values, icing and anemometer breakdown as described in section 5.2.1. Data gaps of Selac 1 have been filled by correlating data of top anemometer with backup anemometer at 92 m(Sonic), 92 m and 32 m. Additionally the top anemometer of Selac 2 was used to fill data gaps. After this for Selac 1 the 1 year period with the highest data availability was chosen. For closing remaining data gaps within the period 2016-11-01 – 2017-10-31, the measured data have been compared to several long-term data sets in order to find the most reliable source for these tasks. Finally the ConWx reanalysis data has been used. Data gaps of Selac 2 have been filled and the measurement period has been extended by correlating data of Selac 2 (top anemometer) with Selac1 (top anemometer after mcp with measurements at mast Selac 1. Remaining data gaps were filled by using ConWx reanalysis data. After this, to decrease the influences of year-to-year wind variations on the results, the valid data for these 1-year periods have been corrected to the long-term average. The resulting wind statistics are therefore valid for a period of 15 years. For the long-term correction a mean-value approach has been applied.
5.3.2 Filling of Data Gaps An advanced time series correlation (MCP) has been performed in order to fill the data gaps and extend the measured time series to a period of 1 year (Selac 2). The MCP-method applied has the added benefit of accurately predicting the wind distribution if sufficiently high quality data is available in both a high temporal and physical resolution. The procedure applied is described in Appendix 12.2. The entire correlation procedure is carried out depending on the wind direction, meaning that a relationship of the wind directions is calculated and that wind speed relationships are calculated for different direction sectors. These relationships are calculated for sectors, which are variable in size and depend on the amount of data in the sector. After the calculation of the correlation parameters, a self-consistency test is performed to measure the quality of the correlation. The results of the self-consistency test can be seen in Figure 5.14 to Figure 5.16 for Selac 1 and in Figure 5.18 and Figure 5.19 for Selac 2. They show the wind speed and direction distributions measured at the site compared to the wind distributions calculated from the reference by means of the correlation procedure for the common measuring period.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 42/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac 1
Figure 5.14: [MCP step 3] Comparison of the wind distributions during overlapping period: site_station-Meas: measured at Selac1 site_station-Calc: calculated for Selac1 using the correlation procedures and the data of the reference anemometer at 92 m (Sonic).
Figure 5.15: [MCP step 4] Comparison of the wind distributions during overlapping period: site_station-Meas: measured at Selac 1 site_station-Calc: calculated for Selac 1 using the correlation procedures and the data of the measurement mast Selac 2.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 43/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.16: [MCP step 5] Comparison of the wind distributions during overlapping period: site_station-Meas: measured at Selac 1 site_station-Calc: calculated for Selac 1 using the correlation procedures and the data the data of ConWx. The differences of the distributions and their most important mean values are small for the wind speed and unusually high for the wind direction, i.e. the transformation of the wind distributions works only modestly well, but can be expected as being usable. Table 5.20 gives an overview of the applied correlation steps in order to fill data gaps.
Table 5.20: Applied MCP steps to the measurements Selac 1 at the site Selac. The percentage of generated data refers to the finally used MCP filled period and not to the measurement period
MCP Generated Intention Site Reference step data 1 Filling of data gaps Selac 1, 92 m (Sonic) Selac 1, 92 m 17% 2 Filling of data gaps Selac 1, 92m (mcp) Selac 1, 32 m 16% 3 Filling of data gaps Selac 1, 94m Selac1, 92 m (mcp) 26% 4 Filling of data gaps Selac 1, 94m (mcp) Selac 2, 84 m 5% 5 Filling of data gaps Selac 1, 94m (mcp) ConWx, 200 m 12% For a quality check of the performed correlation procedure, Table 5.21 shows the mean wind speed and energy content of the wind for the overlapping period of site and long-term measurements.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 44/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.21: Results of the quality test of the correlations for MCP-Step 3 to 5 at measurement mast Selac1.
Site correlated with Selac 1, 92 m (mcp): Selac 1 Measured wind speed [m/s] (time series with data gaps) 7.12 Calculated wind speed [m/s] (filled time series) 7.09 Relative wind speed difference [%] -0.482 Energy content of measured wind speed [m³/s³] 773.7 Energy content of calculated wind speed [m³/s³] 765.7 Relative Energy difference [%] -1.037
Site correlated with Selac 2: Selac 1 Measured wind speed [m/s] (time series with data gaps) 6.54 Calculated wind speed [m/s] (filled time series) 6.67 Relative wind speed difference [%] 1.945 Energy content of measured wind speed [m³/s³] 570.3 Energy content of calculated wind speed [m³/s³] 564.5 Relative Energy difference [%] -1.007
Site correlated with ConWx: Selac 1 Measured wind speed [m/s] (time series with data gaps) 7.34 Calculated wind speed [m/s] (filled time series) 7.31 Relative wind speed difference [%] -0.487 Energy content of measured wind speed [m³/s³] 787.3 Energy content of calculated wind speed [m³/s³] 792.5 Relative Energy difference [%] 0.669 The resulting extended wind speed and direction distributions for mast Selac1 for the 94 m measuring height are presented in Figure 5.17. The main wind direction is North-west and South-west. The mean wind speed during the used period 2016-11-01 – 2017-10-31 is 7.4 m/s for the height of 94 m.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 45/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.17: Wind direction and wind speed distribution measured at mast Selac1 for the site Selac, period 2016-11-01 – 2017-10-31, valid for the height of the top anemometer. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 46/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac 2
Figure 5.18: [MCP step 1] Comparison of the wind distributions during overlapping period: site_station-Meas: measured at Selac 2 site_station-Calc: calculated for Selac 2 using the correlation procedures and the data of measurement mast Selac 1.
Figure 5.19: [MCP step 2] Comparison of the wind distributions during overlapping period: site_station-Meas: measured at Selac 2 site_station-Calc: calculated for Selac 2 using the correlation procedures and the data the data of ConWx. The differences of the distributions and their most important mean values are small for the wind speed and unusually high for the wind direction, i.e. the transformation of the wind distributions works only modestly well, but can be expected as being usable. Table 5.20 gives an overview of the applied correlation steps in order to fill data gaps.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 47/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.22: Applied MCP steps to the measurements Selac 2 at the site Selac. The percentage of generated data refers to the finally used MCP filled period and not to the measurement period
MCP Generated Intention Site Reference step data 1 Filling of data gaps/extend period Selac 2, 84 m Selac 1, 94 m (mcp) 55% 2 Filling of data gaps Selac 2, 84 m ConWx, 75 m 27% For a quality check of the performed correlation procedure, Table 5.21 shows the mean wind speed and energy content of the wind for the overlapping period of site and long-term measurements. Table 5.23: Results of the quality test of the correlations for MCP-Step 1 and 2 at measurement mast Selac 2.
Site correlated with Selac 1: Selac 2 Measured wind speed [m/s] (time series with data gaps) 6.87 Calculated wind speed [m/s] (filled time series) 6.81 Relative wind speed difference [%] -0.991 Energy content of measured wind speed [m³/s³] 686.3 Energy content of calculated wind speed [m³/s³] 682.9 Relative Energy difference [%] -0.489
Site correlated with ConWx: Selac 2 Measured wind speed [m/s] (time series with data gaps) 8.3 Calculated wind speed [m/s] (filled time series) 8.27 Relative wind speed difference [%] -0.395 Energy content of measured wind speed [m³/s³] 1244.4 Energy content of calculated wind speed [m³/s³] 1247.6 Relative Energy difference [%] 0.256 The resulting extended wind speed and direction distributions for mast Selac1 for the 94 m measuring height are presented in
Figure 5.17. The main wind direction is North-west and South-west. The mean wind speed during the used period 2017-07-01 – 2018-06-30 is 7.9 m/s for the height of 84 m.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 48/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.20: Wind direction and wind speed distribution measured at mast Selac2 for the site Selac, extended to the period 2017-07-01 – 2018-06-30, valid for the height of the top anemometer. (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.)
N
W E
S
5.3.3 Comparison of Meteorological Long-term Data UL checked data of several meteorological stations and different data sets of the Reanalysis data model I, MERRA 2 (50m level), ERA Interim at 68 m and 118m, and EMD-ConWX data regarding availability, wind speed, long-term trend, consistency, variation, distance and correlation to the site. Table 5.24 summarizes the main criteria & characteristics, especially the correlation coefficient R² for the chosen short-term period of 2016-11-01 – 2017-10-31 (Selac 1) and 2017-07-01 – 2018-06-30 (Selac 2) and for the closest and most appropriate long-term stations in the area considered by UL. For Selac 1 only the reanalysis long-term data have significant correlation to the site data and are usable for correlation purposes. For Selac 2 the correlation is quite high with the different regarded long-tem data.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 49/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 5.24: Main criteria & characteristics summarized for the considered long-term stations for Selac 1. *Based on the final used long-term period 2016-11-01 – 2017-10-31.
10 m NE 850 hPa SW 925 hPa SW MERRA-2 NW KOPAONIK ERA-I 68 SE ConWx v@200 (Rean. I) (Rean. I) (Rean. I) 50m
Distance [km] 37 230 99 99 66 1.1 31
Correlation Factor R² 60% 58% 88% 84% 31% 68% 65% Nov 2016 - Okt 2017 Start Long-term period @ST 2003/07 2003/07 2003/07 2003/07 2003/07 2003/07 2003/07 station End Long-term period @ST 2018/06 2018/06 2018/06 2018/06 2018/06 2018/06 2018/06 station Scaling factor 103% 97% 100% 100% 97% 100% 98% @ ST station [%] Mean wind speed 3.0 2.4 6.3 5.3 3.6 6.8 3.8 @ LT station [m/s]* Average Availability of Used 99% 100% 100% 100% 100% 100% 100% Years*
Long-term Variability* 10.2% 4.1% 5.3% 3.6% 2.9% 4.3% 3.3%
Table 5.25: Main criteria & characteristics summarized for the considered long-term stations for Selac 2. *Based on the final used long-term period 2017-07-01 – 2018-06-30.
10 m SW 850 hPa SW 925 hPa SW MERRA-2 SE KOPAONIK ERA-I 68 SW ConWx v@200 (Rean. I) (Rean. I) (Rean. I) 50m
Distance [km] 34 37 102 102 30 1.4 19
Correlation Factor R² 91% 84% 95% 94% 77% 85% 87% Jul 2017 - Jun 2018 Start Long-term period @ST 2003/07 2003/07 2003/07 2003/07 2003/07 2003/07 2003/07 station End Long-term period @ST 2018/06 2018/06 2018/06 2018/06 2018/06 2018/06 2018/06 station Scaling factor 97% 95% 96% 96% 96% 98% 97% @ ST station [%] Mean wind speed 3.1 2.6 6.3 5.3 3.6 6.9 3.9 @ LT station [m/s]* Average Availability of Used 99% 100% 100% 100% 100% 100% 100% Years*
Long-term Variability* 9.8% 4.0% 5.2% 3.7% 2.7% 4.5% 3.6%
Figure 5.21 and Figure 5.22 shows the comparison of the monthly mean wind speed of Selac1 mast (measured and correlated data for period 2016-11-01 – 2017-10-31) and Selac2 mast (measured and correlated data for period 2017-07-01 – 2018-06-30) and the considered long-term data sets, respectively.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 50/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.21: Proportional variation of the monthly means of wind speed calculated for the site Selac 1 and for long-term data (period 2016-11-01 – 2017-10-31 = 100%).
Selac1 KOPAONIK 10 m NE (Rean. I) 850 hPa SW (Rean. I) 170%
925 hPa SW (Rean. I) ERA-I 68 SE ConWx v@200 MERRA-2 NW 50m
150%
130%
110%
90% Relative wind speedRelative
70%
50%
Figure 5.22: Proportional variation of the monthly means of wind speed calculated for the site Selac 2 and for long-term data (period 2017-07-01 – 2018-06-30 = 100%).
Selac2 KOPAONIK 10 m SW (Rean. I) 850 hPa SW (Rean. I) 170%
925 hPa SW (Rean. I) ERA-I 68 SW ConWx v@200 MERRA-2 SE 50m
150%
130%
110%
90% Relative wind speedRelative
70%
50%
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 51/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.23: Proportional variation of the yearly means of wind speed calculated for different long-term data (100%: average of period 2003-07-01 – 2018-06-30).
140% KOPAONIK 10 m NE (Rean. I) 850 hPa SW (Rean. I) 925 hPa SE (Rean. I)
ERA-I 68 SE ConWx v@200 MERRA-2 NW 50m 130%
120%
110%
100% Relative wind wind Relative speed
90%
80%
70% 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
In Figure 5.23 several data sets are compared over time. The meteorological station Kopaonik is closest to the site, but it shows a low correlation to the site data (Selac 1). For Selac 2 the correlation is high, but due to an implausible long-term trend before 2009 and the high long-term variability, therefore it was not chosen for long-term scaling. The general outline of trend, availability and variability of the data of Reanalysis 850hPA, SW is reasonable. The comparison of the yearly course shows good correspondence of the data (Selac 1 and Selac 2) during the period 2003-07-01 – 2018-06-30. Before that period, the data of the compared data sets show a larger spread, therefore UL decided not to consider data prior to for the long-term correction.Reanalysis data 850 hPa, Grid point SW has been evaluated as the most reliable available data source for the period 2003-07-01 – 2018-06-30 and has been used for the long-term correction. For Selac 1 the gained scaling factor is verified by ConWx data and for Selac 2 by ERA-I 68 SW as well as the meteorological station Kopaonik.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 52/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.3.4 Long-term Correlation To correct the short-term measurement to a long-term period, the monthly mean values measured at the site have been correlated with the data of 2003-07-01 – 2018-06-30. The resulting correction parameters have been applied to the site data. Table 5.26 presents the wind speed mean value for the short-term period and the resulting wind speed mean value for the long-term period. The given scaling factor for determining the long-term wind conditions has been calculated by dividing the corrected data (long-term) by the primary data (short-term).
Table 5.26: Resulting mean wind speeds and scaling factors for long-term correction. Mast Selac1 Wind speed mean value for the 1 year period 2016-11-01 – 2017-10-31 7.4 m/s Wind speed mean value for long-term period 2003-07-01 – 2018-06-30 7.5 m/s Scaling factor for the site data to period 2003-07-01 – 2018-06-30 100.4 % Mast Selac2 Wind speed mean value for the 1 year period 2017-07-01 – 2018-06-30 7.9 m/s Wind speed mean value for long-term period 2003-07-01 – 2018-06-30 7.6 m/s Scaling factor for the site data to period 2003-07-01 – 2018-06-30 96.0 %
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 53/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.3.5 Wind Speed Statistics after Correlation The resulting wind distributions after performing the long-term correlation are shown in Figure 5.24. The measured wind distribution (repetition of Figure 5.6), as well as the measured and correlated wind distribution for the full 15-year period are also shown for comparison. Due to the correction method applied, the wind direction distribution remained unchanged.
Figure 5.24: Mast Selac1 at the Selac site, measured wind direction and wind speed distribution, valid for 2016-10-28 – 2018-08-12 (above), measured and correlated wind direction and wind speed distribution, valid for 2016-11-01 – 2017-10-31 (middle), and wind direction and wind speed distribution obtained after long-term correction, valid for 2003-07-01 – 2018-06-30 (below). (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.) N
W E
S N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 54/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 55/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.25: Mast Selac2 at the Selac site, measured wind direction and wind speed distribution, valid for 2017-09-01 – 2018-07-09 (above), measured and correlated wind direction and wind speed distribution, valid for 2017-07-01 – 2018-06-30 (middle), and wind direction and wind speed distribution obtained after long-term correction, valid for 2003-07-01 – 2018-06-30 (below). (The mean wind U in the graphs is calculated from the wind speed distribution, which has been fitted to the binned wind data and therefore it is usually not equivalent to the mean wind of the time series data.) N
W E
S N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 56/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
N
W E
S
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 57/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.4 Technical Data of the Wind Turbines The client has selected the wind turbine types:
Config Manufacturer Nominal Rotor Hub Operation Kind of . /Type Rating Diameter Height mode power curve 1* GE 3.8-137 3.83 MW 137 m 110 m Standard Theoretical *Details of each configuration can be found in section 6.3 The calculated energy yield depends strongly on the accuracy of the power curve being used. The magnitude of related uncertainty may be in the order of several percent. If a measured power curve according to 'IEC61400-12' and 'MEASNET' exists for the chosen WT-types, uncertainties can be reduced. If no measured power curve report is available, a reliable power curve warranty by the manufacturer or a warranty in energy yield depending on parallel wind measurements can reduce uncertainties. The power curve of the GE 3.8-137 is a theoretical power curve, for which no power curve measurements are available to UL. Therefore the uncertainty of the power curve is based on a wind dependent theoretical uncertainty (see section 8.1). The thrust coefficient curve is specific for each type of wind turbine and influences the farm efficiency. The manufacturer has submitted the thrust coefficient curve of the wind turbines. Deviations within the thrust coefficient curve may cause deviations in wind farm efficiency and energy yield. Figure 5.26 show the power curves for standard air density, the thrust coefficient and main data of the wind turbines considered for this calculation, which were obtained from the manufacturer. For the calculation, the power curves have been changed to take into account the following effects:
The cut-out wind speed of the wind turbine is specified according to information from the manufacturer. If the cut-out wind speed given by the manufacturer is valid for another averaging time other than ten minutes, it has been recalculated to a ten-minute average. Furthermore, the high-wind speed hysteresis has been taken into account following the procedures as outlined in FGW TR6 [9] and considered as systematical loss (section 7). The air density at each individual wind turbine location has been determined following the guidelines [7] and [10], and based on the measured temperature correlated to the long-term, pressure and humidity conditions on the site in combination with the height above sea level (including hub height). The mean air density has been estimated to be about1.056 kg/m3 for an average height above sea level of 1700 m. The power curves have been corrected to the determined air density for each WT position.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 58/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 5.26: Power curve for configuration 1. Manufacturer, Type: GE Wind Energy GE 3.8-137 Hub height: 110, 134, 160 m Rotor diameter: 137 m Rated power: 3830 kW Power limitation: pitch Generator-Type: asynchronous double-fed Rotor speed: 7.6-12.1 rpm Number of blades: 3 Rotor blade: 67.2 Power curve: theoretical, according to manufacturer, Year 2018 Air density: 1.06 kg/m³ Type of anemometer for measurement of the powercurve: - Thrust curve: theoretical, according to manufacturer, Year 2018 Comment: The values of a theoretical power curve might be uncertain to a significant extent which leads to uncertainties in the calculated energy yield, also. We recommend to demand a power curve from the manufacturer, which is measured and certified according to 'IEC61400-12' and 'MEASNET'.
Wind Electrical power Wind thrust 4500 Speed Power coefficient Speed coefficient 4000 [m/s] [kW] cp [-] [m/s] [-] 3500 3.0 36.0 0.171 3.0 0.980 3.5 105.0 0.313 3.5 0.930 3000 4.0 191.0 0.382 4.0 0.900 2500 4.5 296.0 0.416 4.5 0.870 5.0 422.0 0.432 5.0 0.850 2000 5.5 575.0 0.442 5.5 0.830 1500 6.0 755.0 0.447 6.0 0.830
6.5 967.0 0.451 6.5 0.830 [kW] electricalpower 1000 7.0 1213.0 0.453 7.0 0.830 7.5 1494.0 0.453 7.5 0.820 500 8.0 1807.0 0.452 8.0 0.790 0 8.5 2142.0 0.446 8.5 0.740 0 5 10 15 20 25 9.0 2477.0 0.435 9.0 0.680 w ind speed at hub height [m/s] 9.5 2797.0 0.418 9.5 0.620 10.0 3093.0 0.396 10.0 0.560 10.5 3344.0 0.370 10.5 0.500 11.0 3542.0 0.341 11.0 0.450 11.5 3690.0 0.311 11.5 0.390 1.1 12.0 3774.0 0.280 12.0 0.350 1.0 thrust coefficient c_t 12.5 3821.0 0.250 12.5 0.300 0.9 power coefficient c_p 13.0 3830.0 0.223 13.0 0.270 0.8 13.5 3830.0 0.199 13.5 0.240
] 0.7 -
14.0 3830.0 0.179 14.0 0.210 [
14.5 3830.0 0.161 14.5 0.190 p 0.6 ], c ],
- 0.5
15.0 3830.0 0.145 15.0 0.170 [ t
15.5 3830.0 0.132 15.5 0.160 c 0.4 16.0 3830.0 0.120 16.0 0.140 0.3 16.5 3830.0 0.109 16.5 0.130 0.2 17.0 3830.0 0.100 17.0 0.120 0.1 17.5 3830.0 0.091 17.5 0.110 0.0 18.0 3830.0 0.084 18.0 0.100 0 5 10 15 20 25 18.5 3830.0 0.077 18.5 0.100 w ind speed at hub height [m/s] 19.0 3830.0 0.071 19.0 0.090 19.5 3830.0 0.066 19.5 0.080 20.0 3830.0 0.061 20.0 0.080 20.5 3830.0 0.057 20.5 0.070 21.0 3830.0 0.053 21.0 0.070 21.5 3830.0 0.049 21.5 0.070 22.0 3830.0 0.046 22.0 0.060 22.5 3830.0 0.043 22.5 0.060 23.0 3830.0 0.040 23.0 0.060 23.5 3830.0 0.038 23.5 0.050 24.0 3830.0 0.035 24.0 0.050 24.5 3830.0 0.033 24.5 0.050 25.0 3830.0 0.031 25.0 0.050
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 59/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
5.5 Wind Farm Configuration The client has provided the wind farm configuration. The complete wind farm Selac consists of 27 wind turbines of the same type and 103.41 MW in total. In Figure 5.27 the wind turbine positions are depicted in a map of the site. The coordinates and elevations of each wind turbine can be found in the result tables in section 6.3.1.
Figure 5.27: Wind farm configuration Selac.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 60/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
6. MODEL RESULTS
6.1 Boundary Conditions for the Modeling - CFD
6.1.1 Used Input Data and Applied Modifications The following results are based on the topographical and meteorological data as presented in section 5. The wind data has been corrected to the long-term average of 15 year (period 2003-07-01 – 2018-06-30).
6.1.2 Boundary Conditions for the Modelling - CFD Computational fluid dynamics (CFD) simulations of the wind flow were performed for the Selac site. UL performed the CFD simulations with OpenFOAM (Open Source Field Operation and Manipulation). The code is released as free and open source software (http://www.openfoam.org/). OpenFOAM was used in the simulation environment OF Wind produced by C+ Engineering. A description of the used flow model can be found in the Appendix. The digital terrain model used as a basis for creating the 3D grid is based on the height contour map, which is also used for the calculation with WASP. Here the height contour lines have been transformed to a xyz and finally to a STL file (STereoLithography). A roughness map (WASP map format) has been generated by UL and forms the basis for the definition of the boundary condition at the surface. For this case, UL has chosen a cylindrical domain. The properties of the domain are presented in the Table 6.1. For the simulations, an irregular mesh has been created with 5 different surface refinements at the wind farm area (refer to Figure 6.1). The mesh has been created for different surface refinements and different refinement levels with the help of the OpenFOAM utility SnappyHexMesh. The mesh resolution is 12.5 m inside the wind farm area and decreases towards the domain borders. Table 6.2 gives details of the calculation grid. The surface layer is defined with a vertical expansion ratio of 1.2 and a final layer thickness of 0.8 of the thickness of the respective refinement level.
Table 6.1: Dimensions of the CFD grid used.
Radius / ΔZ X Y Cylindric Domain [m] [m] [m] Centre Point 500960 4760570 Domain height 7980 Smoothing horizon. Distance 5000 Distance constant Z-Level 500 Cutting Radius 18365 No of Surface Refinement 5 Refinement radius 1250 Refinement height 300
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 61/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 6.2: Properties of the Refinement Levels
Refinement Level Resolution [m]Distance (m)No. Cells Share (%) 0 200 12865 1043150 9% 1 100 5000 47033 0% 2 50 3750 215369 2% 3 25 2500 1065279 10% 4 12.5 3750 8762507 79% Sum 11133338
The following images Figure 6.1 and Figure 6.2 show the mesh resolution of the considered simulation domain. 34 different flow situations were integrated into the steady state. The directional resolution is 5 degrees for main wind directions and 20 degrees for non-predominant wind directions of medium or low frequency occurrence. The directional resolution is shown in Table 6.3
Table 6.3: Directional resolution of the CFD simulation runs
Wind direction Directional resolution Figure of cases 0°-130° 10° 130°-210° 20° 210°-220° 10° 220°-250° 5° 250°-360° 10°
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 62/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
0
1
2
3 4
Figure 6.1: View of the computational domain from the top including centre of the domain and 5 different surface refinements (view from the top). Met mast position (white dots) and planned wind turbine positions (red dots) are also shown.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 63/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
0
4 3 2 1
Figure 6.2: View of the computational domain above the terrain from south to north. Vertical slices of the mesh (in front right) and the simulated wind speed for one sector (40 deg, magnitude, left hand side). The slice of the right side shows the mesh refinement (fine mesh, finest resolution: 12.5 m), the 3 interim refinements and towards the edge are the coarse back-ground refinement of 200 m.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 64/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
6.2 Wind Conditions
6.2.1 Results for the Reference Points The locations of the Selac1 and Selac 2 measurement masts and of the LIDAR have been chosen as the reference points. The positions of these points are shown in Figure 5.1.The calculations have been performed according to the CFD calculations as described in section 6.1. The average wind speeds presented here were measured from a specific anemometer type. It may differ from wind speeds measured with other anemometer types. Please note that because of small differences between the Weibull distribution, the binned statistical data and the time series data, as well as due to small rounding errors of the models used, the average wind speeds presented throughout the report may have minor deviations even for the same height and location.
Table 6.4: Wind speed conditions at reference point 1.
Ref-Point 1: Selac1 with coordinates UTM ETRS89, zone 34, 500759 E, 4759195 N wind speed distribution height above ground mean wind speed (Weibull parameters) [m] [m/s] A [m/s] k [ - ] 30.0 6.5 7.3 1.89 50.0 6.9 7.8 1.92 70.0 7.2 8.1 1.93 84.0 7.4 8.3 1.93 94.0 7.5 8.4 1.93 100.0 7.5 8.5 1.93 110.0 7.6 8.6 1.93
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 65/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 6.5: Wind speed conditions at reference point 2
Ref-Point 2: Selac2 with coordinates UTM ETRS89, zone 34, 501722 E, 4763331 N wind speed distribution height above ground mean wind speed (Weibull parameters) [m] [m/s] A [m/s] k [ - ] 30.0 6.4 7.2 1.89 50.0 6.9 7.8 1.88 70.0 7.4 8.3 1.83 84.0 7.6 8.6 1.80 94.0 7.8 8.7 1.78 100.0 7.8 8.8 1.77 110.0 8.0 8.9 1.76
Table 6.6: Wind speed conditions at reference point 3
Ref-Point 3: LIDAR with coordinates UTM ETRS89, zone 34, 501488 E, 4760460 N wind speed distribution height above ground mean wind speed (Weibull parameters) [m] [m/s] A [m/s] k [ - ] 30.0 5.1 5.8 1.84 50.0 5.4 6.1 1.87 70.0 5.7 6.4 1.90 84.0 5.8 6.6 1.91 94.0 5.9 6.7 1.92 100.0 6.0 6.8 1.92 110.0 6.1 6.9 1.93
6.2.2 Model Validation The wind speeds calculated for the mast positions as given in Table 6.4 and Table 6.5 correspond within the uncertainty ranges to the long-term wind speeds determined directly on basis of the measurements. The cross-prediction from one mast to the other shows only small deviations between predicted wind speeds and measured wind speeds. This gives confidence in the modeling of the wind conditions for the wind farm area.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 66/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 6.7: Cross prediction between the different masts at the site
Name Selac1 Selac2 Target Height 94.0 m 84.0 m Ref Value 7.47 m/s 7.62 m/s Predicted Comp. Predicted Comp. Predictor Height Value Index Value Index
Selac1 94.0 m 7.47 100.0% 7.76 101.7%
Selac2 84.0 m 7.70 103.0% 7.62 100.0%
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 67/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
6.2.3 Results for the Wind Farm Area Selac The spatial variation of the mean wind speed for Selac at the hub height of 110 m is depicted as different colors in the map in Figure 6.3. These results are based on the data described in section 5.2.
Figure 6.3: Calculated average wind speed in m/s for the height of 110 m for the wind farm area. The orography of the terrain is depicted as height contour lines. The positions of the reference points and of the wind turbines are marked in the map
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 68/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
6.3 Gross Energy Yield The energy yields are calculated by applying the power curve and thrust curve as described in section 5.4. These results are based on the site-specific time series using meteorological input data, calculated for each of the wind turbine positions according to CFD calculations as described in section 6.1 & Appendix. Table 6.8 summarizes the gross energy yield calculations for the entire wind farm. The following sub- sections show the results for each wind farm configuration and the wind farm area. The net energy yields considering systematic losses are shown in section 7. For comments on the results, please refer to section 10.1.
Table 6.8: Main results for the Selac wind farm
Free Gross Gross Farm Gross Farm Farm Hub Number Farm Average No. WT-Type Energy Yield Energy Yield Energy Yield Capacity Height of WTs Eff. Wind Speed (entire farm) (entire farm) (per WT) Factor [m] [MWh/a] [MWh/a] [MWh/a] [ % ] [m/s] [ % ] 1 GE 3.8-137 110.0 27 364'868 344'904 12'774 94.5 7.5 38.3
Free gross energy yield: No wake losses have been considered
6.3.1 Detailed Results Config. 1: GE 3.8-137, Hub Height 110 m
Input of Gross Energy Calculation: Wind turbine type 27 × GE 3.8-137
Hub height 110 m Overall Rating 102.6 MW Power curve Theoretical according to the manufacturer
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 69/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 6.9: Detailed calculation results of gross energy yield for Configuration 1
No. WT type Hub- Coordinates Height Gross energy yield [MWh/a] Farm Wind height X Y a.s.l. free farm efficiency [m/s] WTG01 GE 3.8-137 110 501'226 4'757'251 1470 12'131 11'511 94.9% 6.9 WTG02 GE 3.8-137 110 501'423 4'757'579 1512 13'570 12'407 91.4% 7.4 WTG03 GE 3.8-137 110 501'543 4'758'059 1565 14'351 12'902 89.9% 7.7 WTG04 GE 3.8-137 110 501'915 4'758'319 1572 14'457 13'229 91.5% 7.8 WTG05 GE 3.8-137 110 502'397 4'758'212 1482 12'064 11'431 94.8% 7.0 WTG06 GE 3.8-137 110 502'889 4'757'919 1466 12'736 12'253 96.2% 7.2 WTG07 GE 3.8-137 110 501'140 4'758'421 1597 14'411 13'226 91.8% 7.7 WTG08 GE 3.8-137 110 500'450 4'758'513 1561 13'627 12'859 94.4% 7.3 WTG09 GE 3.8-137 110 501'282 4'758'873 1590 13'720 12'491 91.0% 7.4 WTG10 GE 3.8-137 110 500'726 4'759'178 1613 14'492 13'384 92.4% 7.6 WTG11 GE 3.8-137 110 500'380 4'759'753 1550 12'545 11'839 94.4% 6.9 WTG12 GE 3.8-137 110 499'971 4'759'751 1485 12'425 11'832 95.2% 7.0 WTG13 GE 3.8-137 110 499'557 4'759'820 1442 12'364 12'073 97.7% 6.9 WTG14 GE 3.8-137 110 500'916 4'759'949 1568 13'047 12'299 94.3% 7.0 WTG15 GE 3.8-137 110 502'125 4'760'721 1615 11'211 10'463 93.3% 6.5 WTG16 GE 3.8-137 110 502'746 4'761'007 1649 13'867 13'103 94.5% 7.6 WTG17 GE 3.8-137 110 502'235 4'761'337 1713 14'791 13'807 93.4% 8.2 WTG18 GE 3.8-137 110 501'968 4'761'639 1675 13'747 12'946 94.2% 7.6 WTG19 GE 3.8-137 110 501'530 4'761'898 1674 13'166 12'590 95.6% 8.0 WTG20 GE 3.8-137 110 501'236 4'762'352 1688 13'434 13'020 96.9% 7.7 WTG21 GE 3.8-137 110 501'858 4'763'162 1716 14'268 13'634 95.6% 7.9 WTG22 GE 3.8-137 110 501'726 4'763'582 1717 15'019 14'389 95.8% 7.8 WTG23 GE 3.8-137 110 501'611 4'764'016 1710 15'003 14'444 96.3% 8.0 WTG24 GE 3.8-137 110 501'454 4'764'478 1695 15'579 15'070 96.7% 8.4 WTG25 GE 3.8-137 110 500'954 4'765'014 1570 12'866 12'419 96.5% 7.5 WTG26 GE 3.8-137 110 500'713 4'765'314 1565 12'764 12'293 96.3% 7.4 WTG27 GE 3.8-137 110 500'643 4'765'681 1557 13'212 12'991 98.3% 7.4 Sum (entire farm): 364'868 344'904 Mean (per WT): 12'774 94.5% 7.5
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 70/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
7. NET ENERGY YIELD
7.1 Systematic Losses The energy yields calculated so far are based on the power curves and the calculated wind conditions and do not take into account reductions due to the limited availability of the wind turbines and electrical losses etc. According to UL’s experience, the following effects can be regarded as potential relevant reductions to the energy output. The determined discount values for these effects (Table 7.1) represent estimations based on experience values. If required, these values can also be determined by project specific calculations with higher accuracy. Only the relevant losses related to the site according to MEASNET [4] and the (TR6), revision 10 [9] have been considered in Table 7.1. The availability given in Table 7.1 is an estimated average availability during normal operation in accordance with the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10 and without consideration of site specific properties. For this site it is recommended to check this topic in detail due to the bedevil reachability particularly during winter time. It includes planned maintenance periods, as these are often included in the availability warranties and it is assumed that a full maintenance contract exists. It should be considered that the availability is often lower for the first months of operation. The availability level to be expected can be assessed more reliable in combination with the assessment of the agreed contractual conditions, which has not been performed within the current report. Guaranteed availabilities can refer to time or to energy in the contracts. This should be clearly clarified with the manufacturer. As well, details outlining the planned maintenance schedule should be determined in the contracts. The grid availability at the site is considered to be negligible. This is a general assumption in accordance with the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10 and without consideration of site specific properties. Electrical losses of wiring and the interconnecting station depend on the project specific design of the grid connection and the involved components. The value stated in Table 7.1 is based on estimations and experiences from wind farms with a similar magnitude and in accordance with the default value as given in the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10, and without consideration of site specific properties. A detailed site specific calculation of electrical losses has neither been made available to UL nor been performed by UL within the ordered scope. The consumption of power is not considered at this place as it is normally considered as operational cost within the wind farm operation. The cut-out wind speed and hysteresis effect has been accounted for in the energy yield calculation. It has been calculated according to the Technical Guidelines for Wind Energy Plants (FGW e.V.), Part 6: "Determination of wind potential and energy yield" (TR6), revision 10.If wind turbines have to be temporarily taken offline from the grid or if turbines are running in a limited power operation mode due to administrative orders, this has to be considered separately. Discounts for such effects have not been taken into account. There is some evidence of icing in the wind data measured at the site. Approximately 9 % of the data have been cut out due to icing and replaced by correlated data. Based on the assumption of a 4 to 1 ratio for meteorological icing to instrumental icing, a rough estimate of 2.3 % has been assumed for icing effects.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 71/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Please note that the losses depend strongly on the strategy of the control system of the wind turbine.Over the lifetime of the wind turbines it can be expected that the rotor blades do not keep their ideal aerodynamic profile, especially the leading edge can erode. Furthermore, dirt, insects, rime & ice and aging of the rotor blade material can impact the aerodynamic characteristics. UL therefore assumes a small loss for rotor blade degradation. Please note that no safety margin deductions of the calculated energy yield related to uncertainties have been applied.
Table 7.1: Systematic reductions for the energy yield
Reduction Efficiency Comment
due to about GE 3.8-137
364.87 GWh Calculation result w/o losses Wake effect 94.5% Calculation Availability Availability of the WTG 97.0% Assumption Balance of Plant Availability 100.0% Assumption Grid availability 100.0% Assumption Electrical Electrical Efficiency in operation 98.0% Assumption Turbine performance Cut-out wind speed and hysteresis 99.7% Calculated acc. TR6, Rev.10 Environmental Calculated based on wind data Icing losses 97.7% evaluation Performance Degradation 99.5% Assumption Curtailments/Operational Strategies Total efficiency 87.1% Total losses 12.9% Sum 317.88 GWh Energy yield with losses
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 72/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
8. QUANTITATIVE ANALYSIS OF UNCERTAINTIES
The uncertainties associated with the meteorological wind data have been assessed and are presented in the following. The procedure is described in [13] under consideration of [17]. The results in the sections above have to be regarded as the most probable energy yield and are determined for a future period of 20 years. The uncertainties presented in the following sections are considered as standard uncertainties. Thus, it is possible that higher deviations occur.
8.1 Wind Uncertainties The uncertainty of the determined wind conditions considers contributions from the measurement itself, the long-term correction of the wind data and the vertical & horizontal wind field modeling. Table 8.1 shows major aspects of the analysis of uncertainties in the Selac wind farm relating to the calculated wind speed. The uncertainty of the measured wind speeds considers the uncertainties of the calibration, anemometer class k [11], mounting effects, data acquisition system, deviations found from the in-situ test and, if applicable, the data integrity uncertainty according [4]. These uncertainties are considered to be independent contributions, i.e. a quadratic summation is applied. All uncertainties are calculated bin-wise and weighted with the frequency of the respective wind speed bin. The uncertainty of the wind measurement at the site is low due to its high standard. It was not possible to perform an in-situ test due to the low availabilities of all sensors at the measurement masts. This has been considered in the wind measurements uncertainties. The uncertainty of the long-term scaling includes the uncertainty of closing data gaps and possibly extending the time series by advanced MCP methods, and the uncertainty of the calculated wind conditions for long-term period expressed with the following points. 1. The statistical uncertainty of correlation, expressed by incomplete mapping of the data. 2. The uncertainty of the correction or correlation procedure (this may possibly coincide with (1)). 3. The uncertainty whether the long-term period of wind or yield data considered is free of inconsistencies and errors. 4. The variation of the long-term average of several years as opposed to a very long (e.g. 30 years) average. 5. Additionally and irrespective of (4) the uncertainty whether the future wind resource (e.g. for the next ten or twenty years) corresponds to the period examined in the past. (Long-term trends or future climate changes are not taken into account.)
In this case, the uncertainty of the long-term scaling is judged as the most important source of uncertainty regarding wind-data mainly due the low data availability. The uncertainty given for the wind modeling, i.e. the horizontal and vertical extrapolation from the measurement position to the wind turbine positions, depends on the distances between measurement and wind turbine hub height, in combination with the topographical and meteorological complexity of the site, the defined guidance levels of [4] and the reliability of the model used. For the layout and the site discussed in this report, the modeling uncertainty is increased, because some planned turbine positions are outside the representative radius of at least one measurement mast, with should be 2 km for complex terrain. This site is assumed to be high complex. Therefore the representative radius for the measurement masts might be even lower than this 2 km.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 73/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The following turbine positions are outside the representativeness radius of at least one measurement device because of a too large distance to the closest measurement device: WTG06, WTG15, WTG16, WTG17, WTG26 and WTG27. For these turbine positions the uncertainty of horizontal extrapolation of the wind conditions is enhanced. The measurement height does fulfill the criterion of 2/3 of the hub height of 110 m, therefore the uncertainty of the vertical extrapolation to hub height is small.
Table 8.1: Summary of the uncertainties relating to the calculated wind speed
Overall Uncertainty in Long Term Wind Resources (Standard Uncertainty) GE 3.8-137
Wind Measurement 2.7%
Long-Term Scaling 7.6%
Horizontal and Vertical Extrapolation 5.9%
Resulting overall uncertainty in wind speed (independent contributions) 10.0%
8.2 Energy Uncertainties With the site specific uncertainties, which are assumed to be stochastic and independent, an overall wind speed uncertainty is calculated for each wind turbine site. The wind speed uncertainty is converted into wind energy uncertainty by a calculated sensitivity of the energy yield in regards to the wind speed (dE/dv). The value of that sensitivity is about 1.4. That means e.g. that a variation of 10 % in wind speed leads to a variation of 14 % in energy yield. It is different for other configurations or wind turbine types. This uncertainty of the wind conditions is combined with the uncertainty of the wind farm efficiency and power curve. The technical characteristics of the chosen wind energy converters at the site (e.g. the power curve) are assumed to be included in the contract with the manufacturer. However, the uncertainties associated with the WT-data from a scientific point of view have been regarded here. Please note the comments regarding the power curve as described in section 5.4. For wind turbine types for which a measured power curve is available, the uncertainty given is derived from the AEP uncertainty of the measurement according to the measurement reports. For wind turbine types for which no measured power curve is available, a theoretical uncertainty is given, depending on the wind speed at each wind turbine location. For GE 3,8-137 a theoretical uncertainty has been applied because no power curve measurement report was available to UL. The uncertainty of the farm efficiency relates to the shading effects from all considered turbines (Selac). It assumes that the wake model has a fixed maximum uncertainty for the calculated wind speed that applies for a fully waked wind farm (farm efficiency below 80%). The actual uncertainty is determined from the actual wake shading/farm efficiency. This wind speed uncertainty is scaled by the sensitivity factor to obtain its energy uncertainty. Thus, this uncertainty is zero if there are no wake effects, while values increase when the impact of the wake model on the wind farm yield becomes larger.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 74/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The final uncertainties of the overall energy yield can be seen in Table 8.2. This uncertainty is related to the long-term mean of the energy yield. Due to the year-to-year variation of the wind, this is not equivalent to the uncertainty of the energy yield of each single year.
Table 8.2: Uncertainties relating to the long-term average of the calculated energy yield; valid for a period of 20 years
Uncertainty in Annual Energy Production (AEP) GE 3.8-137
Overall uncertainties of the wind climate related to the site 14.2%
Uncertainty in power curve 6.5%
Uncertainties of farm efficiency 1.2%
Uncertainty of the calculated losses 1.2%
Overall Uncertainty 15.7%
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 75/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
8.3 Exceedance Probabilities of Energy Yields (P-values) In this section a probability of exceedance is presented, i.e. levels of energy yield that are exceeded with a given probability. For an economic calculation, systematic reductions like grid losses, icing, availability, utility downtime, and reduction margins have to be taken into account by subtracting them from the calculated energy yield. The net energy yield is considered here and includes the energy discounts as stated in section 7. The following Table 8.3 shows the levels of long-term energy yield (20 years of future wind conditions), which are exceeded with a given probability. Values from this table may be the basis for an economic assessment of the project. Please note that these values describe the uncertainty of the long-term energy yield and not the variation of a yearly energy yield around the long-term average.
Table 8.3: Exceedance probabilities for the long-term net energy yield (20 years of future wind conditions), including systematic losses (in GWh/a) for configuration 1 (GE 3.8-137)
Long-Term AEP [GWh/a] and Exceedance Probabilities Wind Farm per WT Free Gross P50 364.9 13.51 Net P50 (12.9% systematical losses) 317.9 11.77 Net P75 284.1 10.52 Net P90 253.8 9.40 AEP Exceedance Exceedance Probability of AEP Wind Farm Probability (Long-Term) [GWh/a] 100% 400.2 5% 382.0 10% 90% 369.7 15% 360.0 20% 80% 351.6 25% 70% 344.1 30% 337.2 35% 60% 330.6 40% 324.2 45% 50% 317.9 50% 40% 311.6 55% 305.2 60%
30% 298.6 65% ExeedanceProbability 291.6 70% 20% 284.1 75% 10% 275.8 80% 266.0 85% 0% 253.8 90% 220 240 260 280 300 320 340 360 380 400 235.6 95% AEP [GWh/a]
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 76/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
9. FURTHER DERIVED RESULTS
9.1 Average Wind Speed Criterion The determination of the average annual wind speed is based on the evaluation of the measured wind data at the site, which have been extrapolated to a long-term period. The evaluation of the wind measurements is described in detail in section 5.2. The wind speeds refer to the anemometer type used for the respective site measurement and may be different for other anemometer types. According to the WTGS classification referring to the standard IEC 61400-1, the average wind speed criterion for a WTGS-class I wind turbine is 10.0 m/s, for class II 8.5 m/s and class III 7.5 m/s. At all positions of the planned wind turbines the class II criterion is kept, but at some turbine positions it is close to the limit.
9.2 Assessment of the Ambient Turbulence Intensity An important component of the WTGS classification, according to IEC 61400-1, is the turbulence intensity. The different ambient turbulence intensity values have been derived according to edition 2 & 3 of the IEC 61400-1. The calculation was done for the position of the measurement mast used for the Selac wind farm site at measurement and hub height. Due to the complex terrain at the site Selac, the turbulence intensity is assumed to be representative only for the area immediately surrounding the reference point. The turbulence intensity may vary strongly throughout the wind farm area. For the evaluation, the turbulence intensity at measurement height has been calculated first. Next, the turbulence intensity has been extrapolated to hub height at the mast positions under the assumption that the standard deviation of wind speed remains constant with height Several quantities related to turbulence intensity are defined within the different IEC-editions and calculated here. These include the following: Characteristic turbulence intensity, which is defined as the mean turbulence intensity plus standard deviation of the turbulence intensity (IEC 61400-1, Edition 2),
Characteristic turbulence intensity at v=15m/s, I15 (IEC 61400-1, Edition 2),
Reference turbulence intensity Iref, which simply is the average turbulence intensity at v=15m/s (IEC 61400-1, Edition 3), Representative turbulence intensity, which is defined as the average turbulence intensity plus 1.28 times their standard deviation, which represents the 0.90 quantile of a normal distribution (IEC 61400-1, Edition 3). The results for the calculation at 15 m/s (to be exact, UL uses the wind speed interval [14;16[ m/s) are shown in Table 9.1. The values of the characteristic turbulence intensity I15 are compared against the limits in Table A.3 and the values of the representative turbulence are compared against the limits in Table A.4. The reference turbulence at 15 m/s is given for informational purposes.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 77/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Table 9.1: Ambient turbulence intensity at the Selac site
Position Ref 1: Selac1 Ref 2: Selac1 Ref 3: Selac2 Ref 4: Selac2
height above ground 94 m 110 m 84 m 110 m
average turbulence for 12.6% 12.4% 12.0% 11.7% all wind speeds
average turbulence at 15 m/s* 8.5% 8.4% 8.2% 8.1%
standard deviation at 15 m/s* 2.9% 2.9% 3.1% 3.0%
Characteristic ambient turbulence I * 15 11.4% 11.3% 11.3% 11.1% according to IEC 61400-1 Edition 2
Reference turbulence I at 15 m/s* ref 8.5% 8.4% 8.2% 8.1% according to IEC 61400-1 Edition 3
Representative turbulence at 15 m/s* 12.2% 12.1% 12.2% 12.0% according to IEC 61400-1 Edition 3
*more exact: average of wind speed interval [14;16[ m/s.
Figure 9.1 shows the bin-averaged characteristic ambient turbulence intensity in comparison to the turbulence limits of the IEC 61400-1 Edition 2. Figure 9.2 shows the bin-averaged representative ambient turbulence in comparison to the limits of IEC 61400-1, Edition 3. If the determined turbulence intensities are below the curves indicating the turbulence subclass limits, the guideline is kept. The edition 3 refers to wind speed ranges of [0.2 vref;0.4 vref], with vref being the defined extreme wind speed limit, resulting in the following wind speed intervals: IEC class I: 10.0-20.0 m/s IEC class II: 8.5-17.0 m/s IEC class III: 7.5-15.0 m/s
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 78/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Figure 9.1: Characteristic ambient turbulence intensity in comparison to the turbulence subclasses of IEC 61400-1, edition 2, at the Selac site 35% IEC 61400-1 ed2 turbulence class A IEC 61400-1 ed2 turbulence class B Selac1, height: 94 m Selac1, height: 110 m Selac2, height: 84 m 25% Selac2, height: 110 m
15% Characteristic Ambient Turbulence Intensity Turbulence Ambient Characteristic
5% 2 4 6 8 10 12 14 16 18 20 22 24 26
Wind Speed [m/s]
Figure 9.2: Representative ambient turbulence intensity in comparison to the turbulence subclasses of IEC 61400-1, edition 3, at the Selac site 35% IEC 61400-1 ed3 turbulence class A IEC 61400-1 ed3 turbulence class B IEC 61400-1 ed3 turbulence class C Selac1, height: 94 m Selac1, height: 110 m Selac2, height: 84 m 25% Selac2, height: 110 m
15% Representative Ambient Turbulence Intensity Turbulence Ambient Representative
5% 2 4 6 8 10 12 14 16 18 20 22 24 26
Wind Speed [m/s]
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 79/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The characteristic ambient turbulence intensity at the site meets the requirements of IEC turbulence subclasses A and B. The representative ambient turbulence intensity at the site meets the requirements of IEC turbulence subclasses A, B and C.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 80/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
10. COMMENTS
10.1 Project Specific UL has no project specific comments on this project. Following the guidance below might lower the uncertainties of future energy yield calculations for the site under review or might help to reduce project risks. If a measured power curve according to 'IEC61400-12' [6] and 'MEASNET' [4]will be available for GE 3.8-137 the calculation can be repeated to verify the applied theoretical power curve and to reduce the uncertainty of the power curve. With respect to the complexity of the flow conditions at the site, the masts are not sufficiently representative for all wind turbine positions. Distances are partly exceeding the limits given in [4] and [9]. The data availability of the measurement is not sufficient according to the guidelines. The losses for the availability of the WTG given in section 7.1 is only considered with a standard value. Due to the high complexity of the site and the bedevil reachability particularly during winter time this topic should be checked.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 81/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11. APPENDIX A - ADDITIONAL INFORMATION
11.1 Photo-Documentation of the Site Point of photo-documentation: 500759 E, 4759195 N (Selac1) North North-east
East South-east
South South-west
West North-west
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 82/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Point of photo-documentation: 501722 E, 4763331 N (Selac2) North North-east
East South-east
South South-west
West North-west
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 83/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11.2 Documentation of the Measurements
11.2.1 Photo-Documentation of the Mast and Sensors Selac1 overview image
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 84/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac1 detailed pictures Measurement mast top (mast height 94 m) Measurement mast from below
v@72 m dit@72 m v@52 m
v@32 m
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 85/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac2 overview image
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 86/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac2 detailed pictures Measurement mast top (mast height 84 m) Measurement mast from below
v@61 m dit@61 m v@41 m, dir@41
v@21 m
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 87/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11.2.2 Photo-Documentation of the LIDAR
Figure A.1: LIDAR at the site Selac
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 88/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11.2.3 Monthly Wind Statistics and Availabilities Table A.1: Monthly measured wind speeds and availabilities at Selac 1
Selac1@94m
Date availability v mean [m/s] v std [m/s] v max [m/s] Okt 16 13% 6.67 0.81 8.67 Nov 16 69% 8.25 0.72 10.03 Dez 16 76% 8.04 0.67 9.67 Jan 17 43% 5.93 0.35 6.77 Feb 17 68% 9.06 0.79 11.04 Mrz 17 75% 8.12 0.97 10.57 Apr 17 59% 6.35 0.79 8.34 Mai 17 5% 5.06 0.57 6.46 Jun 17 100% 5.70 0.72 7.56 Jul 17 100% 6.29 0.79 8.31 Aug 17 52% 5.70 0.73 7.58 Okt 17 62% 6.16 0.64 7.75 Nov 17 90% 8.33 0.74 10.23 Dez 17 43% 11.15 1.08 13.90 Jan 18 58% 7.89 0.55 9.23 Feb 18 17% 10.95 1.20 13.88 Mrz 18 1% 13.41 0.96 15.98 Mai 18 89% 6.88 0.82 8.96 Jun 18 100% 6.39 0.76 8.28 Jul 18 99% 6.13 0.79 8.13 Aug 18 39% 4.96 0.62 6.52
Average 58.5% 7.11 - -
Table A.2: Monthly measured wind speeds and availabilities at Selac 2
Selac2@84m
Date availability v mean [m/s] v std [m/s] v max [m/s] Sep 17 57% 8.39 0.95 10.77 Okt 17 77% 6.03 0.58 7.52 Nov 17 54% 8.84 0.81 10.86 Dez 17 0% 8.78 1.22 11.84 Mai 18 88% 6.81 0.74 8.70 Jun 18 100% 6.46 0.68 8.19 Jul 18 29% 5.41 0.67 7.12 Average 39.6% 6.96 - -
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 89/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11.2.4 Monthly Availability Distribution Mast Selac1, v@94 m
Remaining Data Gap Selac1, v@94 Filled Measured 100.0%
80.0%
60.0%
40.0% Monthly Availability MonthlyAvailability [%]
20.0%
0.0%
Mast Selac2, v@84 m
Remaining Data Gap Selac2, v@84 Filled Measured 100.0%
80.0%
60.0%
40.0% Monthly Availability MonthlyAvailability [%]
20.0%
0.0% 07/2017 08/2017 09/2017 10/2017 11/2017 12/2017 01/2018 02/2018 03/2018 04/2018 05/2018 06/2018 07/2018
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 90/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
11.2.5 Calibration Sheets of Used Anemometers Selac 1
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 91/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 92/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 93/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 94/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Selac2
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 95/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 96/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
12. MODEL RESULTS – WASP
The following WAsP results have been used only for comparison purposes and validation of the CFD model.
12.1.1 Gross Energy Yield The energy yields are calculated by application of the power curve and thrust curve as described in section 5.4. These results base on the site-specific Weibull statistics as meteorological input data, calculated for each of the wind turbine positions according to the European Wind Atlas methods as described in the European Wind Atlas of Risø National Laboratory [1] using the ''Wind Atlas Analysis and Application Program'' called WASP [2]. The following parameters have been applied for all energy calculations:
Technical availability: 100% Grid and transformer losses: 0% Power consumption of wind turbines: 0 No safety reduction of the calculated energy yield has been carried out. Table A.1 summarises the gross energy yield calculations for the entire wind farm. The following sub- sections show the results for each wind farm configuration and the wind farm area.
Table A.1: Main WASP results for wind farm Selac
Free Gross Gross Farm Gross Farm Farm Hub Number Farm Average No. WT-Type Energy Yield Energy Yield Energy Yield Capacity Height of WTs Eff. Wind Speed (entire farm) (entire farm) (per WT) Factor [m] [MWh/a] [MWh/a] [MWh/a] [ % ] [m/s] [ % ] 1 GE 3.8-137 110.0 27 373'292 352'668 13'062 94.5 7.5 39.2
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 97/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
12.1.2 Detailed Results Config. 1:GE 3.8-137, Hub Height 110 m
No. WT type Hub- Coordinates Height Gross energy yield [MWh/a] Farm Wind height X Y a.s.l. free farm efficiency [m/s] WTG01 GE 3.8-137 110 501'226 4'757'251 1470 12'409 11'743 94.6% 6.8 WTG02 GE 3.8-137 110 501'423 4'757'579 1512 12'758 11'512 90.2% 7.0 WTG03 GE 3.8-137 110 501'543 4'758'059 1565 13'612 12'029 88.4% 7.4 WTG04 GE 3.8-137 110 501'915 4'758'319 1572 14'330 13'142 91.7% 7.7 WTG05 GE 3.8-137 110 502'397 4'758'212 1482 12'972 12'347 95.2% 7.2 WTG06 GE 3.8-137 110 502'889 4'757'919 1466 13'425 12'881 95.9% 7.4 WTG07 GE 3.8-137 110 501'140 4'758'421 1597 13'788 12'594 91.3% 7.4 WTG08 GE 3.8-137 110 500'450 4'758'513 1561 13'807 13'028 94.4% 7.4 WTG09 GE 3.8-137 110 501'282 4'758'873 1590 13'682 12'423 90.8% 7.3 WTG10 GE 3.8-137 110 500'726 4'759'178 1613 14'536 13'436 92.4% 7.6 WTG11 GE 3.8-137 110 500'380 4'759'753 1550 13'702 12'999 94.9% 7.4 WTG12 GE 3.8-137 110 499'971 4'759'751 1485 13'267 12'703 95.7% 7.3 WTG13 GE 3.8-137 110 499'557 4'759'820 1442 13'137 12'790 97.4% 7.2 WTG14 GE 3.8-137 110 500'916 4'759'949 1568 13'438 12'771 95.0% 7.2 WTG15 GE 3.8-137 110 502'125 4'760'721 1615 13'085 12'173 93.0% 7.2 WTG16 GE 3.8-137 110 502'746 4'761'007 1649 14'761 13'916 94.3% 8.0 WTG17 GE 3.8-137 110 502'235 4'761'337 1713 15'156 14'106 93.1% 8.1 WTG18 GE 3.8-137 110 501'968 4'761'639 1675 13'966 13'107 93.9% 7.6 WTG19 GE 3.8-137 110 501'530 4'761'898 1674 14'007 13'403 95.7% 7.8 WTG20 GE 3.8-137 110 501'236 4'762'352 1688 14'367 13'908 96.8% 7.8 WTG21 GE 3.8-137 110 501'858 4'763'162 1716 14'920 14'222 95.3% 8.0 WTG22 GE 3.8-137 110 501'726 4'763'582 1717 14'806 14'230 96.1% 7.9 WTG23 GE 3.8-137 110 501'611 4'764'016 1710 15'075 14'570 96.7% 8.1 WTG24 GE 3.8-137 110 501'454 4'764'478 1695 15'123 14'675 97.0% 8.2 WTG25 GE 3.8-137 110 500'954 4'765'014 1570 12'866 12'394 96.3% 7.3 WTG26 GE 3.8-137 110 500'713 4'765'314 1565 13'177 12'697 96.4% 7.4 WTG27 GE 3.8-137 110 500'643 4'765'681 1557 13'119 12'870 98.1% 7.3 Sum (entire farm): 373'292 352'668 Mean (per WT): 13'826 13'062 94.5% 7.5
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 98/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
12.2 General Description of Energy Yield Assessment Procedure
Site Inspection During the site visit an inspection and survey of the proposed wind farm site is performed and documented with photographs. For the necessary height and roughness description of the location the related maps are compared with the topography and, if necessary, modified with information regarding obstacles, vegetation and roughness. The measurement masts at the site are inspected during the visit to identify possible disturbing influences on the measurement by shadings or unsatisfactory installation. It is particularly important to detect and eliminate possible error sources, which can lead to measurement errors. The relevant heights, dimensions and orientations of the measurement installations are measured as far as possible and checked for consistency with the information provided by the measurement company. The measurement system is analyzed with respect to the data quality.
Data Assessment and Evaluation A general review and assessment of the available meteorological data material is performed. The data are assessed regarding their quality and usability for the intended purposes. The used data have been checked for detectable measuring, recording or conversion errors and inconsistencies. The completeness of the data is checked and the influence of data gaps is determined.
MCP Correlation Procedure (Advanced Measure-Correlate-Predict-algorithm) In order to perform a time series correlation between the measurement data of a reference station and a target station (located at the wind farm site), the time series of the measured wind data are compared. The relationships of wind speeds and wind directions between them are determined for the common overlapping measuring period. Afterwards, the correlation parameters obtained by this method will be applied on the long-term time-series of the reference station in order to calculate an artificial long-term time-series for the target station. To determine the wind speed relationship, a polynomial regression is applied on the wind speed data for certain wind direction sectors. This procedure is called the advanced Measure-Correlate-Predict- algorithm (MCP). The wind direction sectors taken into account are variable and optimized following a good correlation. Starting with a first assumption, the determined wind speed relationships for all sectors are optimized following good results, which is a minimal deviation of the wind speed distribution measured at the site and the wind speed distribution obtained by the MCP-method [12]. For the wind directions, a relationship between the reference and the target station is assumed. The parameters of this function are optimized regarding minimal deviations of wind direction distributions. Hence the comparison of the wind speed and wind direction distributions measured at the target site and those obtained by the MCP-method during the overlapping period can be interpreted as self- consistency test of the correlation procedure and its parameters. The difference of the distributions from the self-consistency test should be considered as an error that can be expected while applying the correlation results. This error is not determined by the mean wind speed and the mean cubic speed only because the interest focuses on the energy content of the wind. Usually, the wind energy produced by wind turbines depends on a power of V that is between 1.5 and 2.5 for nowadays turbines. If all relevant wind situations (e.g. wind directions) occur during the overlapping period, and the results of the self-consistency test provide confirmation, the determined correlation parameters are expected to be applicable on the wind distribution measured during the long-term period of the reference station.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 99/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
The application of the correlation parameters results in the expected wind distribution at the target site during the reference period. This is often referred to as extrapolated wind distribution at the target site, which will be the basis for further wind resource assessments.
Long-term Correlation The data sets recorded are valid only for a relatively short period. For a long-term determination of wind speed and energy yield the long-term data set should cover a period of at least 10 years, otherwise the results are influenced by seasonal and year-to-year wind variations. Even a medium period of a few years is generally not free from year-to-year variations. As experience has shown, many stations show a decreasing trend in mean wind speeds caused by growing trees and construction of new houses or have inconsistencies in the data. Under these circumstances, it is better to use a shorter period of higher consistency and as far as possible without trends. Usually measurement data for a period of several months or years are available for the wind farm site. With long-term wind data of a suitable meteorological measurement station in the same region, the measured data of the site can be extrapolated to the long-term data. For the extrapolation, the simultaneously measured time series data of the site and the meteorological station are compared and evaluated to test whether the wind speed and the wind direction measurements of the two stations correlate, i.e. whether a relation exists between them. If short-term and long-term time series show suitable correlation behavior, the long-term extrapolation is carried out based on mean values of the wind speed. To assure that this long-term conversion is permitted, most of the wind directions, wind speed classes and thermal stability situations must be included in the short time measurements.
Assessment of the Wind Characteristics The determination of the average annual wind speed is performed according to the methods and conditions described in the European Wind Atlas of Risø National Laboratory [1] using the ''Wind Atlas Analysis and Application Program'' called WASP [2]. For calculating the wind energy potential of a given site, meteorological base data have to be available. These are normally on-site measurement data or meteorological data from a suitable data source generally representative for the site, which are validated by energy yield and availability information from neighbouring wind farms. Site and measurement stations have to be in the same area with the same wind climatic conditions (up to 100 km distance in flat, about 2 km kilometers for complex flow conditions), so that wind conditions at higher heights (geostrophic winds) are comparable. The wind speed measured at a meteorological station depends the regional weather conditions in the surrounding area, the topography (orography, roughness, and obstacles) in an area up to 10 kilometers, and the local thermally driven effects. Therefore, measurements from this station are valid for this site only and cannot be used directly for a neighboring site as this generally has a different topography for determining wind speed and energy output of WTs and may be differently affected by local thermal conditions. The "European Wind Atlas" is a calculation procedure, which corrects site specific measurement data according to the influences of the topography and extrapolates these data to a general non-site specific, regional wind climate (wind atlas data, "WASP lib" data). To calculate the wind climate at another site from this general wind climate, the same procedures are used in opposite ways, taking into account the site-specific topography. The model is based on the physical principals of flows in atmospheric boundary layers. It takes into account the following effects: the reduction of wind speed caused by vegetation and other surface roughness, shadow effects of buildings and other obstacles and changes
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 100/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
in wind speed as well as wind direction caused by orographic effects (mountains, valleys). Due to some simplifications these models have known limitations, which lead to uncertainties, especially in situations with steep orography (increased uncertainty of spatial wind variation and vertical wind profiles) and in situations with strong effects of near obstacles (e.g. for a low measurement height). For application of this model, the surrounding of the site under consideration and of the meteorological base is described in assigning roughness lengths to the surface characteristics. The positions and heights of obstacles are determined and an orographic map of the surrounding is made. Changes of roughness lengths and orography are taken into account within a distance of 10 km. Based on this site description, the average wind speed and wind statistics at the site can be calculated from the regional wind climate. In detail, for a specific height the frequency distribution of the wind speed (Weibull distribution) is calculated for each of 12 wind direction sectors. With these site-specific distributions and the power curve of each single WT, the average annual energy yield is calculated. To do a correct selection and assessment of the input data, considerable experience with the principles and sensitiveness of the wind atlas method is required. The meteorological data has a great influence on the results and has to be appropriately selected with respect to its location and measuring period.
Energy Yield Prediction and Wind Farm Micro-Siting To calculate the energy yield of a wind farm, the annual energy yield of the single wind turbines has to be calculated as well as the energy yield losses caused by mutual shading effects. These calculations are performed on the basis of the "Park Model" developed by Risø National Laboratory, Denmark. N.O. Jensen developed and used the mathematical model of the wake of WTs in Risø [2]. The basic input data for this calculation are the frequency distributions of the wind speed at each turbine position of the planned wind farm, consisting of the A and k parameters of the Weibull distributions. These quantities are calculated according to the European Wind Atlas methods (see above). The model of a wake behind a wind turbine uses impulse and mass conservation to determine the wind speed behind the rotor. A linear expansion of wake is assumed. The wind speed deficit inside the wake is calculated using the thrust coefficient curve ct. The opening angle depends on the turbulence intensity and it can be calculated using empirical relations. To calculate energy yield and farm efficiency of a wind farm, the installation geometry of the farm and the overlapping of the single wakes have to be taken into account. For these tasks, the Risø model uses a method of linear wake-superposition. Summarizing the calculation procedure uses the following input data:
WTs-characteristic, i.e. power curve P(v), thrust coefficient curve ct(v), hub height and diameter of the rotor coordinates of each WT in the wind farm different meteorological data for the turbine positions The results of the wind farm calculation are the energy yield and the wind farm efficiency for each wind turbine and for the whole farm. The total farm efficiency is the ratio of the total electrical energy of the farm (taking into account wake losses) to the sum of the energy of all single WTs, assuming an undisturbed flow.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 101/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
12.3 Description of the CFD Model For the CFD simulations the validated open source model OpenFOAM (Open Source Field Operation and Manipulation) is used. The code is released as free and open source software (http://www.openfoam.org/). OpenFOAM was used in the simulation environment O.F.Wind produced by C+ Engineering. OF Wind provides a graphical user interface for the OpenFOAM case setup, the simulation monitoring and the post processing. The simulation software OpenFOAM is a widely used flow model core with various possibilities for adjustments to specific application problems and is the preferred CFD model in research as well as an industry society. The model provides a numerical solution of the equations of flow motion, namely the Reynolds-Averaged Navier-Stokes Equations, which have been widely applied and validated. Besides the pre- and post-processing environment, the O.F. Wind extensions enclose the model parameterisation and implementation of boundary layer relevant parameter. As turbulence model the SST k-omega turbulence model is used. The model is applied on an unstructured grid, which is defined in the most interesting areas of the model domain. The most interesting location can be considered with more and smaller cells. The size of the mesh can be chosen individually according to the demand of accuracy. The transmission of the mesh for area more away is determined by several parameters. The characteristics in the following table help to create a huge mesh including the desired properties. The adjustment of the mesh (different layers, different mesh resolutions and boundary conditions) has been done by the help of the OpenFOAM mesh generation tool SnappyHexMesh.
Table A.2: Used Settings for the Mesh creation
Expansion Ratio of Surface Layer 1.2 Final Layer Thickness 0.8 Minimum Number of per Layer Refinement Level 5
As boundary conditions for the surface, the usual meteorological roughness length is defined. As the top boundary type the shear stress has been set to be constant. The inflow wind conditions are obtained from preliminary one-dimensional simulations of the atmospheric boundary layer. The use of the model for wind potential calculation consists of the solution of a series of wind flow simulations in the quasi-stationary mode, to calculate the flow field for specific wind situations, which are defined by constant wind speed and wind direction at the inflow boundary. These wind situations cover the relevant range of the observed wind situations at the site. After performing the simulations for the determined wind situations, the relations derived from the resulting flow fields are interpolated and applied on the measured wind speed and wind direction time series to calculate wind statistics for the site.
12.3.1 Details of Post-processing This subsection provides a detailed description of the processing of the time series. In order to render the following explanation more readable, only one met mast and one wind turbine is considered. In practice, with several met masts, the results obtained from the masts are generally interpolated by weighting each mast with the inverse of the squared distance to the turbine.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 102/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
Processing of wind speed: For each simulated flow situation the wind speed at the position of the wind turbine v_T(dir) and at the position of the mast v_M(dir) is calculated. Afterwards the ratio rv(dir) = v_T(dir) / v_M(dir) is calculated. This ratio is linearly interpolated with respect to wind direction and then applied to the time series of the measured wind speed and direction at the mast to obtain a time series of wind speed at the turbine position.
Processing of wind direction: For each simulated flow situation the wind direction at the position of the wind turbine d_T(dir) and at the position of the mast d_M(dir) is calculated. Afterwards the difference dd(dir) = d_T(dir) - d_M(dir) is calculated. This difference is linearly interpolated with respect to wind direction and then applied to the time series of measured wind direction at the mast to obtain a time series of wind direction at the turbine position.
12.4 Definitions of IEC-61400-1
12.4.1 Turbulence Intensity & Extreme Wind Table A.3 and Table A.4 show the characteristics of the WTG classes for wind turbines according to IEC 61400-1, edition 2 and 3.1. The wind speeds in the tables are defined as 10-min averages.
Table A.3: WTGS classes according to IEC 61400-1, ed.2 [18]. Be aware that within ed. 2 I15 is identical to the characteristic turbulence intensity at 15m/s WTGS Class I II III IV S
Vref (m/s) 50 42.5 37.5 30
Vave (m/s) 10.0 8.5 7.5 6.0 Values to be
A I15 (-) 0.18 0.18 0.18 0.18 Specified a (-) 2 2 2 2 by the
B I15 (-) 0.16 0.16 0.16 0.16 Designer a (-) 3 3 3 3
Table A.4: WTGS classes according to IEC 61400-1, ed.3.1 [19]. Be aware that within ed. 3.1 Iref denotes the average ambient turbulence intensity at 15m/s, which is different from both the representative TI commonly used in Ed. 3 and from the characteristic TI (used in Ed. 2) Wind turbine I II III S class
Vref (m/s) 50 42.5 37.5 Values to be
A Iref (-) 0.16 Specified
B Iref (-) 0.14 by the
C Iref (-) 0.12 Designer
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 103/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
12.4.2 Topographical Complexity of the Site Table A.5 and Table A.6 show the terrain complexity indicators for wind turbines according to IEC 61400-1, edition 3 and 3.1.
Table A.5: Terrain complexity indicators according to IEC 61400-1, ed.3 [19]
Maximum terrain variation Distance range from wind from a disc with radius Max. Slope of fitted plane turbine 1.3*zhub fitted to the terrain (m)
<5*zhub <0.3*zhub
<10*zhub <10° <0.6*zhub
<20*zhub <1.2*zhub
Table A.6: Terrain complexity indicators according to IEC 61400-1, ed.3.1 [19]
Distance range from Max. Slope of fitted Maximum terrain Sector amplitude wind turbine plane variation (m)
<5*zhub 360° <0.3*zhub
<10*zhub 30° <10° <0.6*zhub
<20*zhub 30° <1.2*zhub
12.5 Used Software UL used several tools and programs for evaluation and correlation of the wind data including the following software for the investigation in hand: Wind Atlas Analysis and Application Program (WASP), version 11.6, build 18, Risø National Laboratory, Roskilde, Denmark. WindPRO, version 3.1.617 EMD International A/S, Denmark OpenFoam The Open Source CFD Toolbox, Simulation software, GNU General Public License, Unix, Linux version 1.6.x www.OpenFOAM.org O.F.Wind, version 1.4.3.68 Graphical Interface for OpenFOAM, IB Fischer CFD+engineering GmbH, Munich, Germany 2014 ArcGIS version 10, geographic information system, Esri, http://www.esri.com/software/arcgis/
12.6 References [1] I. Troen, E.L. Petersen: European Wind Atlas. Risø National Laboratory, Roskilde, Denmark, 1990. [2] G. Mortensen, L. Landberg, I. Troen, E.L. Petersen: Wind Atlas Analysis and Application Program (WASP), Risø National Laboratory, Roskilde, Denmark, 1993 and updates. [3] I.Katic, J.Højstrup; N.O.Jensen: A Simple Model for Cluster Efficiency, European Wind Energy Association Conference and Exhibition, 7-9 October 1986, Rome, Italy. [4] MEASNET: Evaluation of Site-Specific Wind Conditions, Version 2, April 2016. [5] IEA: IEA Recommendation 11: Wind Speed Measurement and Use of Cup Anemometry, 1st Ed., 1999.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 104/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
[6] International Electrotechnical Commission (IEC): IEC61400-12-1 Wind turbines - Part 12-1: Power performance measurements of electricity producing wind turbines, 1st ed., 12/2005. [7] International Electrotechnical Commission (IEC): IEC 61400-12-1 Ed.2: Wind turbines – Part 12- 1: Power performance measurements of electricity producing wind turbines, 03/2017. [8] ISO/IEC 17025:2005 – General requirements for the competence of testing and calibration laboratories. [9] FGW e.V.-Fördergesellschaft Windenergie und andere Erneuerbare Energien: Technical Guidelines for Wind Turbines, Part 6, „Determination of Wind Potential and Energy Yield“, Revision 10, Berlin, 2017. [10] ISO 2533: Standard Atmosphere, International Organization for Standardization, 1975-05-15, corrected version1978-12-15 [11] T.F. Pedersen, et al.: ACCUWIND – Classification of 5 Cup AnemometersAccording to IEC 61400-12-1, Risø National Laboratory, Roskilde, Denmark, May 2006. [12] V. Riedel, M. Strack, H.P. Waldl: Robust Approximation of functional Relationships between Meteorological Data: Alternative Measure-Correlate-Predict Algorithms. Proceedings EWEC 2001, Copenhagen. [13] M. Strack, W. Winkler: Analysis of Uncertainties in Energy Yield Calculation of Wind Farm Projects, Dewi Magazin No. 22, Wilhelmshaven, February 2003. [14] A. Albers, H. Klug, D. Westermann: Outdoor comparison of cup anemometers, proceedings of DEWEK 2000, DEWI, Wilhelmshaven. [15] A. Albers, H. Klug: Open Field Cup Anemometry, Proceedings of European Wind Energy Conference 2001, Kopenhagen, Denmark. [16] E. Kalnay et al.: The NCEP/NCAR 40-Year Reanalysis Project, Bulletin of the American Meteorological Society, Volume 77, Issue 3, pp. 437–471 [17] International Organization for Standardization: Guide to the Expression of Uncertainty in Measurement. First edition, 1993, corrected and reprinted, Geneva, Switzerland, 1995. [18] IEC: IEC61400-1 Wind turbine generator systems - Part 1: Safety Requirements, 2nd Ed., 02/1999. [19] IEC: IEC61400-1, Consolidated Version, Wind turbines - Part 1: Design Requirements, 3.1rd Ed. 04/2014. [20] Rienecker, M. M., M.J. Suarez, R. Gelaro, R. Todling, J. Bacmeister, E. Liu, M.G. Bosilovich, S.D. Schubert, L. Takacs, G.-K. Kim, S. Bloom, J. Chen, D. Collins, A. Conaty, A. da Silva, et al., 2011. MERRA - NASA's Modern-Era Retrospective Analysis for Research and Applications. Journal of Climate, Vol. 24, No. 14, 3624-3648. doi: 10.1175/JCLI-D-11-00015.1. [21] Michael G. Bosilovich et al.: MERRA-2: Initial Evaluation of the Climate, Technical Report Series on Global Modeling and Data Assimilation, Volume 43, NASA/TM–2015-104606/Vol. 43, Sept.2015. [22] Berrisford, P., Dee, D., Fielding, K., Fuentes, M., Kallberg, P., Kobayashi, S. and Uppala, S., (2009) The ERA-Interim Archive. ERA Report Series. 1. Technical Report. European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading. [23] Jon Olauson: ERA5: The new champion of wind power modeling? Renewable Energy, Sweden, September, 2017.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT
Selac Site Page 105/105 Status: Draft Ref. No.: UL-GER-WP17-12005195-02 Issue: 00 of Final
[24] EMD ConWX Mesoscale Data, Copenhagen, Denmark 2015 [25] IEA: Ground-based vertically-profiling remote Sensing for Wind Resource Assessment, 1st Edition, Jan 2013. [26] Wind Measurement Installation Report, Site Selac, DEWI-GER-WM16-11491633-01.01, 2017-01-02 [27] Wind Measurement Installation Report, Site Selac II, DEWI-GER-WM17-11858772-01.00 [28] Protocol Installation Lidar Selac Kosovo, Notus Energy 2018-03-06
[29] LIDAR Verification report GLGH-4275 17 14682 271-R-0008, Rev. A: Independent analysis and reporting of ZephIR LiDAR performance verification executed by ZephIR Ltd. At Pershore test site, DNV-GL; 2018-01-18 [30] René Cattin: WIND TURBINE BLADE HEATING – DOES IT PAY?, DEWEK, Bremen, 2010. [31] A. Albers, H. Klug, D. Westermann: Power Performance Verification. Proceedings of the EWEC, Nice, 1999.
SOWI Kosovo L.L.C 07 September 2018
36-LO-F0853 – Issue 6.0
SUPPLIED TO MARKO LIPOSAK, ENLIGHT RENEWABLE ENERGY LTD. ON 13 MAY 19 01:10:04 GMT