HIGH-RESOLUTION NUMERICAL SIMULATION OF WIND ENERGY RESOURCE IN HAINAN PROVINCE AND ITS OFFSHORE WATERS

With high resolution （1 kin）, the distribution of wind energy resources in Hainan province and over its offshore waters is numerically simulated by using the Wind Energy Simulation Toolkit （WEST） model developed by Meteorological Research Branch of Environment Canada. Compared with observations from eight coastal anemometric towers and 18 existing stations in the province, the simulations show good reproduction of the real distribution of wind resources in Hainan and over its offshore waters, with the relative error of annual mean wind speed being no more than 9% at the 70-m level. Moreover, based on the simulated results of WEST grids that are closest to where the eight wind towers are located, the annual mean wind speeds are further estimated by using the Danish software Wasp （Wind Atlas Analysis and Application Program）. The estimated results are then compared with the observations from the towers. It shows that the relative error is also less than 9%. Therefore, WEST and WEST＋WAsP will be useful tools for the assessment of wind energy resources in high resolution and selection of wind farm sites in Hainan province and over its offshore waters.

Assessment of wind energy potential in China

China wind atlas was made by numerical simulation and the wind energy potential in China was calculated. The model system for wind energy resource assessment was set up based on Canadian Wind Energy Simulating Toolkit (WEST) and the simulating method was as follows. First, the weather classes were obtained depend on meteorological data of 30 years. Then, driven by the initial meteorological field produced by each weather class, the meso-scale model ran for the distribution of wind energy resources according each weather class condition one by one. Finally, averaging all the modeling output weighted by the occurrence frequency of each weather class, the annual mean distribution of wind energy resources was worked out. Compared the simulated wind energy potential with other results from several activities and studies for wind energy resource assessment, it is found that the simulated wind energy potential in mainland of China is 3 times that from the second and the third investigations for wind energy resources by CMA, and is similar to the wind energy potential obtained by NREL in Solar and Wind Energy Resource Assessment(SWERA) project. The simulated offshore wind energy potential of China seems smaller than the true value. According to the simulated results of CMA and considering lots of limited factors to wind energy development, the final conclusion can be obtained that the wind energy availability in China is 700～1 200 GW, in which 600～1 000 GW is in mainland and 100～200 GW is on offshore, and wind power will become the important part of energy composition in future.

Comparative Analysis for Evaluating Wind Energy Resources Using Intelligent Optimization Algorithms and Numerical Methods

Statistical distributions are used to model wind speed,and the twoparameters Weibull distribution has proven its effectiveness at characterizing wind speed.Accurate estimation of Weibull parameters,the scale(c)and shape(k),is crucial in describing the actual wind speed data and evaluating the wind energy potential.Therefore,this study compares the most common conventional numerical(CN)estimation methods and the recent intelligent optimization algorithms(IOA)to show how precise estimation of c and k affects the wind energy resource assessments.In addition,this study conducts technical and economic feasibility studies for five sites in the northern part of Saudi Arabia,namely Aljouf,Rafha,Tabuk,Turaif,and Yanbo.Results exhibit that IOAs have better performance in attaining optimal Weibull parameters and provided an adequate description of the observed wind speed data.Also,with six wind turbine technologies rating between 1 and 3MW,the technical and economic assessment results reveal that the CN methods tend to overestimate the energy output and underestimate the cost of energy($/kWh)compared to the assessments by IOAs.The energy cost analyses show that Turaif is the windiest site,with an electricity cost of$0.016906/kWh.The highest wind energy output is obtained with the wind turbine having a rated power of 2.5 MW at all considered sites with electricity costs not exceeding$0.02739/kWh.Finally,the outcomes of this study exhibit the potential of wind energy in Saudi Arabia,and its environmental goals can be acquired by harvesting wind energy.

Discussion on the Assessment Method of Wind Energy Resources by Using Regional Meteorological Data

The exploitation status of wind energy resources was analyzed, and the distribution of wind energy resources and regional meteorological stations were introduced, and then the assessment method of wind energy resources by using data from regional meteorological station was studied taking Huangjin Regional Meteorological Station in Xinning County in Hunan Province for example, besides, corresponding software was compiled. By means of SQL database and program, the method was used simply and easily and had positive meaning for the development of wind energy resources and excavation of wind farm in inland region.

Research on Leading Edge Erosion and Aerodynamic Characteristics of Wind Turbine Blade Airfoil

The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on the Reynolds Averaged Navier-Stokes equations(RANS).The results indicate that when sand-induced holes and small pits are involved as leading edge wear features,they have a minimal influence on the lift and drag coefficients of the airfoil.However,if delamination occurs in the same airfoil region,it significantly impacts the lift and resistance characteristics of the airfoil.Specifically,as the angle of attack grows,there is a significant decrease in the lift coefficient accompanied by a sharp increase in the drag coefficient.As wear intensifies,these effects gradually increase.Moreover,the leading edge wear can exacerbate flow separation near the trailing edge suction surface of the airfoil and cause forward displacement of the separation point.

Reliability Assessment Considering the Coordination of Wind Power, Solar Energy and Energy Storage

风光储联合发电系统并网后必须采取策略与系统之间实现协调调度与运行才可在保证可靠性的前提下最大化利用可再生能源，但现有的可靠性评估中还缺少对大规模风光储联合发电系统协调运行的考虑。针对此问题，基于序贯蒙特卡罗仿真方法，建立了风电、光伏和储能系统的发电可靠性评估模型，并提出了新的协调调度策略。模型综合考虑了风速、太阳光辐照度、环境温度以及2种新能源发电技术的能量变换特性和储能系统的充放电约束等因素。这些模型被应用到IEEERTS79中，通过在Matlab中编制程序进行仿真计算，考察不同的协调运行策略、联合发电系统容量配置以及储能特性对于系统裕度的影响。评估结果可为联合发电系统并网规划与设计提供参考。

Assessment of the Tidal Current Energy Resources and the Hydrodynamic Impacts of Energy Extraction at the PuHu Channel in Zhoushan Archipelago,China

An unstructured model FVCOM(The Unstructured Grid Finite Volume Community Ocean Model)with sink momentum term was applied to simulate the tidal current field in Zhoushan Archipelago,China,with focus on the region named PuHu Channel between Putuo Island and Hulu Island.The model was calibrated with several measurements in the channel,and the model perform-ance was validated.An examination of the spatial and temporal distributions of tidal energy resources based on the numerical simula-tion revealed that the greatest power density of tidal energy during spring tide is 3.6kWm^(−2)at the northern area of the channel.Two parameters were introduced to characterize the generation duration of the tidal array that causes the temporal variation of tidal current energy.The annual average available energy in the channel was found to be approximately 2.6MW.The annual generating hours at rated power was found to be 1800 h when the installed capacity of tidal array is approximately 12MW.A site for the tidal array with 25 turbines was selected,and the layout of the array was configured based on the EMEC specifications.Hydrodynamic influence due to the deployment of the tidal array was simulated by the modified FVCOM model.The simulation showed that the tidal level did not significantly change because of the operation of the tidal array.The velocity reduction covered a 2km^(2)area of the downstream the tidal array,with a maximum velocity reduction of 8cms−1 at mid-flood tide,whereas the streamwise velocity on both sides of the farm increased slightly.

Assessment of Tidal Range Energy Resources Based on Flux Conservation in Jiantiao Bay, China

La Rance Tidal Range Power Station in France and Jiangxia Tidal Range Power Station in China have been both long-term successful commercialized operations as kind of role models for public at large for more than 40 years. The Sihwa Lake Tidal Range Power Station in South Korea has also developed to be the largest marine renewable power station with its installed capacity 254 MW since 2010. These practical applications prove that the tidal range energy as one kind of marine renewable energy exploitation and utilization technology is becoming more and more mature and it is used more and more widely. However, the assessment of the tidal range energy resources is not well developed nowadays. This paper summarizes the main problems in tidal range power resource assessment, gives a brief introduction to tidal potential energy theory, and then we present an analyzed and estimated method based on the tide numerical modeling. The technical characteristics and applicability of these two approaches are compared with each other. Furthermore, based on the theory of tidal range energy generation combined with flux conservation, this paper proposes a new assessment method that include a series of evaluation parameters and it can be easily operated to calculate the tidal range energy of the sea. Finally, this method is applied on assessment of the tidal range power energy of the Jiantiao Harbor in Zhejiang Province, China for demonstration and examination.

Review of Experimental-Numerical Methodologies and Challenges for Floating Offshore Wind Turbines

Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to find a more accurate,economic and efficient approach,which can be utilized to predict the full-scale global dynamic responses of FOWTs.In this paper,a literature review of experimental-numerical methodologies and challenges for FOWTs is made.Several key challenges in the conventional basin experiment issues are discussed,including scaling issues;coupling effects between aero-hydro and structural dynamic responses;blade pitch control strategies;experimental facilities and calibration methods.Several basin experiments,industrial projects and numerical codes are summarized to demonstrate the progress of hybrid experimental methods.Besides,time delay in hardware-in-the-loop challenges is concluded to emphasize their significant role in real-time hybrid approaches.It is of great use to comprehend these methodologies and challenges,which can help some future researchers to make a footstone for proposing a more efficient and functional hybrid basin experimental and numerical method.

Wind Shear Investigation for Site-Specific Wind Turbine Performance Assessment

The wind energy assessment studies are generally performed referring to neutral stability conditions for the atmosphere; this is considered a good hypothesis because neutral conditions characterize the high wind situations. However the increasing size of modem multi megawatt wind turbines allows to produce energy even in low wind regimes and non-neutral conditions can involve significant production period. In such situations the variations of the vertical wind shear can affect the energy production in a sensible way and it could be fundamental to investigate how atmospheric stability and orography can affect the wind profile and the power conversion. In this paper meso-scale numerical data, CFD modeling and remote sensed wind data were used in order to analyze such behavior and to understand how wind shear influences the energy content and the discussion about how to adjust the power curve to the site specific conditions.

Wind Turbine Power Output Assessment in Built Environment

In future planning of the city, it is very important to consider the proper intelligent integration of renewable energy sources into the built environment for developing smart cities. Analysis of the wind velocity profile in the built environment is very important for finding out the energy content in the wind and also to analyze the performance of wind turbines in the built environment. In this study, building topologies of smart city are investigated for finding out the wind velocity profile and the wind turbine power output in the built environment. The wind velocity distribution across buildings is numerically simulated by using commercial CFD (Computational Fluid Dynamics) software CFD-ACE+. Wind turbine power output is estimated by using the power curve of real commercial wind turbine and wind velocity distribution simulated by CFD software. It has been observed that the wind is accelerated in the intervening space between the buildings irrespective of distance between the walls of adjacent buildings under the condition, which are investigated in this study. The wind is accelerated across buildings, and is reduced rapidly after blowing through buildings, and recovered gradually. Since the wind is accelerated in the intervening space between buildings and reduced in the area at the back of buildings, a wind turbine should be installed at the area at the back of the buildings and located on center between the buildings. In this work, it is observed that size dimensions and layout of the building are effective in realizing a smart city for utilizing renewable energy such as wind turbine in the built environment.

Wind Power Revenue Potential: Simulation for Finland

Potential revenue from wind power generation is an important factor to be considered when planning a wind power investment.In the future,that may become even more important because it is known that wind power generation tends to push electricity wholesale prices lower.Consequently,it is possible that if a region has plenty of installed wind power capacity,revenue per generated unit of electricity is lower there than could be assumed by looking at the mean electricity wholesale price.In this paper,we compare 17 different locations in Finland in terms of revenue from wind power generation.That is done by simulating hourly generation with three different turbine types at two different hub heights and multiplying that by the hourly electricity spot price for years 2018 and 2019.Estimated revenues differ greatly between locations and turbine types,major factor being technical potential i.e.,the amount of electricity generated.Differences between revenues per generated MWh seem to be small,however,the smallest figures being on the western coast where installed capacities are also the largest in Finland.

Forty-year investigation of wave power in energetic region of Persian Gulf in Iranian territorial waters by using short-term and new long-term stability assessment parameters

The wave power in high potential area of the northern Persian Gulf(near to Iranian coastal areas)is assessed by taking into account the temporal and spatial distributions of wave power for a period of forty years.For this purpose,assimilated wind data of European Centre for Medium-Range Weather Forecasting Interim Reanalysis(ERA-Interim),and hydrography data of General Bathymetric Chat of the oceans(GEBCO)are used as SWAN model.Seven locations are investigated in the study area by considering the amount of coefficient of variation,the amount of average annual power,and the short-term and a new long-term(decadal variability index)power stability assessment parameters.The results showed more stability in the eastern parts of the study area and concluded that a narrow line between the point which is in the middle and another point which is in the eastern middle part of the study area may be the best locations for more investigation and the feasibility study for energy converter farms.Also,it is found that the middle part of the study region with about 2.5 kW/m power is the most energetic area.It is concluded that the dominant direction of wave power distribution in all points is the northeast,and this dominant direction has not changed during the forty-year period.It is observed that the mean annual energy increases with a slight slope in the total 40 a,and this increasing trend is more obvious in the fourth decade.Although it is observed that the wave power of the second decade has the most stability and the least variation,the wave power in the fourth decade has the most variation.Moreover,the results showed that the study region’s wave power increase by approximately a mean change rate of 0.027 kW/(m·a);and the maximum change rate of wave power was in the northwest part and the minimum change rate of wave power was in the southeast part which were about 0.036 kW/(m·a)and 0.014 kW/(m·a),respectively.

水风光大基地资源分析要求和方法

近年来,由于“极热无风”“晚峰无光”“云来无光”“冬季枯水”甚至极端天气导致的“汛期反枯”等气象问题加剧了能源保供的压力,能源开发方式将不能局限于单一能源品种,而应呈现多能互补方式,清洁可再生的“水风光”多能互补开发,可以最大程度地带动流域内风光资源的开发利用,弥补新能源发电的出力不足,是保障电量可靠供给的有效方式。水风光资源的特性与时空分布是水风光多能互补规划设计和调度运行的基础与依据,本文首先论述了水风光资源特性及其评估方法,进而开展对水风光互补特性的研究,最后针对水风光大基地在规划设计和调度运行中的资源分析方法进行论述。

基于测风塔和WT数值模拟的贵州山地风能资源评估——以册亨县为例

【目的】精细化评估贵州复杂山地地形下的风能资源分布,对贵州风能资源开发利用具有重要的指导意义。【方法】利用贵州册亨县境内5座测风塔2020年11月—2021年9月观测资料及其周边气象站数据,采用基于计算流体力学模型的Meteodyn WT软件,对整个册亨县境内山地风能资源进行模拟分析评估。【结果】册亨县风资源较好的区域主要分布在中部的秧坝镇、者楼镇、丫他镇以及北部的坡妹镇和冗渡镇的较高山脊处,具备一定开发利用价值;受册亨独特的地理位置和地形地势以及季风的多重影响,册亨县风能资源有较明显的月变化特征,11月—次年5月风资源较好。【结论】基于测风塔和WT数值模拟的风能资源评估方法模拟误差较小,适用于贵州山地复杂地形下的风能资源评估。

海上风电场宏观选址与风能资源储量估算

基于高时空分辨率风能资源数据库、地理空间规划数据库、风电机组机型数据库等,系统梳理中国海上风能资源储量评估的技术方法和技术流程,初步建立海上风电场宏观选址的综合评价方法体系,并利用地理信息系统(GIS)开展中国渤海和南海海域的风能资源储量估算。评估结果显示:南海风能资源较为丰富,年平均风速6.35~9.75 m/s,渤海多年平均风速相对较低,年平均风速6.30~7.70 m/s,两大海域风能资源可开发潜力均较大。渤海100 m高度的风能资源可开发量总量为526.8 GW,其中近海风能资源技术开发量约为353 GW,深远海风能资源技术开发量约为174 GW;南海海域广东、海南100 m高度的风能资源技术开发量分别为540.8、506.0 GW,其中近海分别为177.7、41.9 GW,深远海分别为363.1、464.2 GW;北部湾海域100m高度的风能资源技术开发量总量为63.3 GW、其中近海59.9 GW,深远海3.4 GW。截至2022年底,中国渤海、南海和北部湾各省区海上风电装机容量仅为技术可开发量的1.9%。

Analysis of Offshore Wind Power： Application to Southern Thailand

This paper presents an analysis of a pre-feasibility study of a 10 MW offshore wind power project in Nakhon Si Thammarat province, southern Thailand. The wind speeds at the hub heights of large scale wind turbine generators （WTG）, i.e. 80-100 m, were extrapolated using monthly mean wind shear coefficients and the l/7th exponent. Using WAsP 9.0, the annual energy production from several models of offshore wind farms using different WTG was analyzed. The capacity factor and the cost of energy were then computed. Using best available estimates, the analysis shows that the estimated annual mean offshore wind speeds at 80-100 m were in the range of 6.4 and 8.3 m/s. The annual energy production by the wind farm from nine models of wind turbine generators were in the range of 20-39 GWh/year, corresponding to a capacity factor in the range of 26-46%, while the cost of energy was 12-15 US cent/kWh.

WindSim软件在复杂地形风电场风能资源评估中的应用

复杂地形的风能资源评估研究对于风电事业的发展具有极为重要的意义。作者利用基于计算流体力学(CFD)方法的风能资源评估系统软件WindSim对我国复杂地形新疆托克逊县境内某风电场2007年的风资源情况进行了模拟,并将模拟结果与测风塔观测结果进行对比分析。模拟结果表明,WindSim软件对我国复杂地形地区平均风速的模拟能力比较好,10m、40 m、50 m、70 m高度的月平均风速的平均相对误差分别是12.91%、10.21%、9.68%、12.91%。同时,WindSim软件不仅可以较为准确地模拟出该区域2007年的主导风向,而且对该年的有效风速频率的模拟效果也很好。此风电场风能资源模拟试验说明,该地区具有十分丰富的可供开发利用的风能资源,进一步说明WindSim软件对我国复杂地形地区的风能资源评估工作具有很好的参考和应用价值。

风资源评估中WindSim水平分辨率的敏感性试验

利用基于计算流体力学(CFD)的风能资源评估系统软件WindSim,在不同水平网格分辨率条件下对我国黄土高原地区陕西靖边县境内某风电场2010年7月～2011年6月的风资源情况进行了模拟,并将模拟结果与测风塔观测结果进行了对比分析。结果表明,在低水平网格分辨率下,WindSim对风能资源的空间分布模拟主要以海拔高度为基础,对局地地形的影响并不能很好地反映,模拟风速误差较大;提高分辨率后,对风能资源空间分布的模拟能力明显提高,模拟风速的误差也显著减小。但不同分辨率下的风速频率和风向频率分布并无显著差别,不能很好地体现出风能特性。通过估算发电量发现,输入不同测风塔资料得到的发电量差异较大,说明在地形较为复杂的风电场,应多布设测风塔,以期得到较为准确的发电量结果。

中国海风能和波浪能的长期趋势与演变规律分析

海上风能和波浪能是极具吸引力的可再生能源。在气候变化的背景下,基于ERA5再分析数据产品研究并对比了1979~2020年的中国海风能和波浪能的长期历史趋势和多尺度演化规律;采用Mann-Kendall检验和Theil-Sen方法分别量化了趋势显著性、趋势幅度和突变点。结果表明,海上风能和波浪能在气候特征和长期趋势上存在显著差异。风能的增长趋势在统计上不显著,平均增长率为每10年0.55%;而波浪能呈现强劲的增长趋势,以每10年4.8%的正向速率上升。海浪特性普遍向大波高、长周期和高能量的海况转移。不同季节和地区的长期趋势区别明显,其中冬季是风与波资源储量和趋势增长的优势季节、东海等开阔海域显示了风能和波浪能持续开发的潜力。基于这些分析结果,进一步探究了风浪能和涌浪能的时空多样性,揭示了海浪场的强化以及风波系统在能量场中的差异主要由涌浪的资源量所贡献,并受涌浪变化的调制。这些结果为海上资源评估、风和海浪气候预测以及海洋工程等众多领域提供了科学参考。