Statistical Characteristics and Mapping of Near-Surface and Elevated Wind Resources in the Middle East
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Statistical characteristics and mapping of near-surface and elevated wind resources in the Middle East Dissertation by Chak Man Andrew Yip In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy King Abdullah University of Science and Technology Thuwal, Kingdom of Saudi Arabia November, 2018 2 EXAMINATION COMMITTEE PAGE The dissertation of Chak Man Andrew Yip is approved by the examination committee Committee Chairperson: Georgiy L. Stenchikov Committee Members: Marc G. Genton, Gerard T. Schuster, Kristopher B. Kar- nauskas 3 ©November, 2018 Chak Man Andrew Yip All Rights Reserved 4 ABSTRACT Statistical characteristics and mapping of near-surface and elevated wind resources in the Middle East Chak Man Andrew Yip Wind energy is expected to contribute to alleviating the rise in energy demand in the Middle East that is driven by population growth and industrial development. However, variability and intermittency in the wind resource present significant chal- lenges to grid integration of wind energy systems. The first chapter addresses the issues in current wind resource assessment in the Middle East due to sparse meteorological observations with varying record lengths. The wind field with consistent space-time resolution for over three decades at three hub heights over the whole Arabian Peninsula is constructed using the Modern Era Retrospective-Analysis for Research and Applications (MERRA) dataset. The wind resource is assessed at a higher spatial resolution with metrics of temporal variations in the wind than in prior studies. Previously unrecognized locations of interest with high wind abundance and low variability and intermittency have been identified in this study and confirmed by recent on-site observations. The second chapter explores high-altitude wind resources that may provide al- ternative energy resources in this fossil-fuel-dependent region. This study identifies areas favorable to the deployment of airborne wind energy (AWE) systems in the Middle East and computes the optimal heights at which such systems would best operate. AWE potential is estimated using realistic AWE system specifications and assumptions about deployment scenarios and is compared with the near-surface wind generation potential concerning diurnal and seasonal variability. The results show 5 the potential utility of AWE in areas in the Middle East where the energy demand is high. The third chapter investigates the potential for wind energy to provide a con- tinuous energy supply in the region. We characterize the wind power variability at various time-scales of power operations to illustrate its effects across the Middle East via spectral analysis and clustering. Using a high-resolution dataset obtained from Weather Forecasting and Research (WRF) model simulations, this study showcases how aggregate variability may impact operation, and informs the planning of large- scale wind power integration in the Middle East in light of the scarcity of observational data. 6 ACKNOWLEDGEMENTS The research reported in this dissertation was supported by King Abdullah Uni- versity of Science and Technology (KAUST) and Saudi Basic Industries Corporation (SABIC) under grant number RGC/3/1815-01. I want to thank my advisor Prof. Georgiy Stenchikov for his wisdom, kindness, and patience, and Dr. Udaya Bhaskar Gunturu for the many collaborative thoughts and actions throughout my research journey. I'd also thank Dr. Stoitchko Kalenderski for the historical simulations on WRF, Dr. Suleiman Mostamandi for his help in the setup and configuration of the simulations, and Dr. Alexander Ukhov for his help in computing environment. I have my parents to thank for their unlimited support always and my dear for saving me in the many last-minute crises throughout my time at KAUST. 7 TABLE OF CONTENTS Examination Committee Page 2 Copyright 3 Abstract 4 Acknowledgements 6 List of Figures 9 List of Tables 14 1 Introduction 15 1.1 Near-surface wind resource assessment . 18 1.2 Elevated wind resource assessment . 19 1.3 High-resolution simulation of wind resource and spatial analysis . 20 2 Surface wind resource analysis 21 2.1 Overview . 22 2.2 Methods . 25 2.2.1 Data . 25 2.2.2 Metrics . 27 2.3 Results . 30 2.3.1 Abundance . 30 2.3.2 Variability . 40 2.3.3 Intermittency . 40 2.4 Discussions . 43 3 Airborne wind resource analysis 52 3.1 Overview . 52 3.2 Methods . 54 3.2.1 Wind Speed Maxima (WSM) . 56 3.2.2 Altitudes of WSM . 56 8 3.2.3 Capacity factor . 57 3.2.4 Deployment assumptions . 58 3.3 Results . 58 3.3.1 Average WSM . 59 3.3.2 Variability in WSM . 61 3.3.3 Altitude of WSM . 63 3.3.4 Variability in WSM altitudes . 63 3.3.5 Regional AWE potential . 64 3.3.6 Comparison with near-surface wind resources . 65 3.4 Discussions . 68 4 Variability mitigation with spatial clustering 70 4.1 Overview . 70 4.2 Methods . 74 4.2.1 Data . 74 4.2.2 Methods . 75 4.3 Results . 77 4.3.1 Dominant time scales of variability . 78 4.3.2 Clustering analysis . 80 4.3.3 Cluster variance . 80 4.3.4 Clustering characteristics . 82 4.3.5 In-cluster variability reduction . 82 4.4 Discussions . 84 5 Summary 87 References 90 Appendices 101 9 LIST OF FIGURES 2.1 Median WPD (W m−2) computed at 50 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uniform except for values beyond 100 W m−2 and below 30 W m−2. Large extreme values beyond the 98-percentile in the spatial domain are masked in grey. Selected locations of prior studies are shown. 31 2.2 Categorized median WPD (fig. 2.1) at 50 m AGL into three regimes: regime I where median WPD is above 67 W m−2, regime II where me- dian WPD is from 46 W m−2to67 W m−2, and regime III where median WPD is below 46 W m−2. Elevation contours at 400 m intervals are drawn using elevation data from MERRA. Selected locations of prior studies are shown. 32 2.3 Average WPD (W m−2) computed at 50 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uniform except for values beyond 200 W m−2 and below 60 W m−2. Large extreme values beyond the 98-percentile in the spatial domain are masked in grey. Selected locations of prior studies are shown. 33 2.4 Changes of median WPD (fig. 2.1) and average WPD (fig. 2.3) at 80 m and 140 m from those at 50 m AGL. Large extreme values beyond the 98-percentile in the spatial domain are masked in grey. The color scale is uniform except for values beyond 45%. 37 2.5 Average wind speed (m s−1) computed at 100 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uni- form except for values beyond 6:6 m s−1 and below 2:4 m s−1. Selected locations of prior studies are shown. 38 2.6 Differences in the average wind speed (m s−1) at 100 m AGL between our calculation and that from estimation of Vestas (Vestas - MERRA) are illustrated with a color scale that is uniform except for values be- yond 2:5 m s−1 and below −2:5 m s−1. Selected locations of prior stud- ies are shown. The MERRA dataset is regridded to 1 km resolution by nearest neighbor for illustration. 39 10 2.7 Robust coefficient of variation computed at 50 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uniform except for values beyond 1:45 and below 1:15. Selected locations of prior studies are shown. 41 2.8 Availability of wind resource computed at 50 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uniform except for values beyond 0:45 and below 0:1. Large extreme values beyond the 98-percentile in the spatial domain are masked in grey. Selected locations of prior studies are shown. 42 2.9 Changes of availability (fig. 2.8) at 80 m and 140 m from those at 50 m AGL. Large extreme values beyond the 98-percentile in the spa- tial domain are masked in grey. The color scale is uniform except for values beyond 40% and below 15%. 43 2.10 Median length of wind episode (h) computed at 50 m, 80 m, and 140 m AGL using the wind fields reconstructed from the MERRA data. The color scale is uniform except for values beyond 10 h. Selected locations of prior studies are shown. 44 2.11 Country map in the Middle East . 46 2.12 Illustration of a skewed distribution of WPD at Yanbu . 47 2.13 Average wind speed (m s−1) is computed at 50 m AGL using the wind fields reconstructed from the MERRA data. Selected locations of prior studies (table 2.1) are shown. 48 2.14 Fractional change in WPD at 80 m and 140 m from 50 m over temporal median of roughness lengths . 49 2.15 Distribution of fractional changes in rCV at 80 m and 140 m from 50 m out of 1638 grid cells . 50 2.16 Distribution of differences in MEL at 80 m and 140 m from 50 m out of 1638 grid cells . 51 3.1 (a) Definition of wind speed maxima (WSM) and its associated altitude (H), where the size of the box indicates the magnitude of the wind speed (b) Power curve, power (kW) as a function of wind speed (m/s), of a lift-type groud-based AWES of 3 MW rating.