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This paper presents a systematic literature review of urban wind energy harnessing in built environments. In line to foster decarbonisation in urban areas of tropical countries with decentralised renewable energy technologies, such as small wind turbines in buildings, this research has been carried out. To provide a comprehensive foundation on the topic, urban wind assessment research for various purposes was reviewed, where 48 studies for energy harnessing purposes were classified by country, region and methods. The methodologies are divided into six stages, of which environmental assessment and resilience analysis are scarce. Due to tropical countries being exposed to atmospheric events that historically cause human and material losses, potential future research could be made in line with resilience analysis through metrics that are key to the proper mass deployment of building-integrated wind turbine systems. Of 66 methods for wind prospecting, the most used are on-site measurement, computational fluid dynamics simulation and numerical climate prediction, which represent 49 %, 22 % and 17 %, respectively. Other decision-making techniques are presented with the aim of addressing new ways in strategic planning to promote the use of this technology. [Display omitted] • Urban wind energy research does not deem energy resilience analysis. • Few evaluations of urban wind energy have been carried out in the tropics. • Hurricanes represent a hazard for building-integrated wind turbines. • On-site measurement and CFD simulation are the most adopted methods. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential of wind energy in six coastal locations in the Kingdom of Morocco, namely Al Hoceima, Tetouane, Assila, Essouira, Laayoune and Dakhla. First, a literature review of recent wind energy potential studies in different locations worldwide has been conducted. Thereafter, the status of wind energy development in Morocco along with its achievements and challenges has been reported. A comprehensive literature review of the mathematical distributions used to fit wind data and procedures employed to estimate the shape and scale parameters of the Weibull distribution is as well presented. The second part of this paper investigated the statistical analysis of wind data based on hourly wind speeds and directions considered for a period of five years between 2011 and 2015. The analysis has shown that the Weibull model independently of the used algorithms for estimation scale and shape parameters, presented an accurate description of the frequencies of actual wind data. By the end, annual energy outputs and capacity factors were derived for wind turbines of various sizes between 225 and 900 kW. The results showed that Dakhla is the most suitable location for harnessing the wind power, while Laayoune has been identified as the second most suitable site. Both Dakhla and Laayoune were found to be suitable for the grid-connected wind energy conversion system while Assila and Essouira have been categorized to be appropriate for the stand-alone wind power applications. [ABSTRACT FROM AUTHOR]

For isolated power networks supplied by intermittent energy sources, several doubts have emerged regarding the impact of the uncertainties on the networks reliability. This paper performs optimal sizing for a hybrid power system with wind/energy storage sources based on stochastic modeling of historical wind speed and load demand. The autoregressive moving average is used to stochastically model the uncertainty of the load demand/wind speed and, the sequential Monte Carlo simulation is performed to chronologically sample the system states. The contribution of the paper can be summarized as follows: (1) an objective function based on self-adapted evolutionary strategy in combination with the Fischer–Burmeister algorithm is proposed to minimize the one-time investment and annual operational costs of the wind/energy storage sources; and (2) the effect of the cycle efficiency and charging/discharging rate of different energy storage units on the system cost is investigated under different reliability and load shifting levels. The computational performance of the proposed optimization solver is proven in order to obtain the minimum possible investment cost. The presented case studies in this paper provide the decision makers with the flexibility to choose the suitable capacity installation at different values of reliability and load shifting levels. [ABSTRACT FROM AUTHOR]

Since the early 1980s, wind power technology has experienced an immense growth with respect to both the turbine size and market share. As the demand for large-scale wind turbines and lor operation & maintenance cost continues to raise, the interest on condition monitoring system has increased rapidly. The main components of wind turbines are the focus of all CMS since they frequently cause high repair costs and equipment downtime. However, vast quantities of their failures are caused due to a bearing failure. Therefore, bearing condition monitoring becomes crucial. This paper aims at providing a state-of-the-art review on wind turbine bearing condition monitoring techniques such as acoustic measurement, electrical effects monitoring, power quality, temperature monitoring, wear debris analysis and vibration analysis. Furthermore, this paper will present a literature review and discuss several technical, financial and operational challenges from the purchase of the CMS to the wind farm monitoring stage. [ABSTRACT FROM AUTHOR]

Wind power is the most reliable and developed renewable energy source over past decades. With the rapid penetration of the wind generators in the power system grid, it is very essential to utilize the maximum available power from the wind and to operate the wind turbine (WT) at its maximal energy conversion output. For this, the wind energy conversion system (WECS) has to track or operate at the maximum power point (MPP). A decent variety of publication report on various maximum power point tracking (MPPT) algorithms for a WECS. However, making a choice on an exact MPPT algorithm for a particular case require sufficient proficiency because each algorithm has its own merits and demerits. For this reason, an appropriate review of those algorithms is essential. However, only a few attempts have been made in this concern. In this paper, different available MPPT algorithms are described for extracting maximum power which are classified according to the power measurement i.e. direct or indirect power controller. Merits, demerits and comprehensive comparison of the different MPPT algorithms also highlighted in the terms of complexity, wind speed requirement, prior training, speed responses, etc. and also the ability to acquire the maximal energy output. This paper serves as a proper reference for future MPPT users in selecting appropriate MPPT algorithm for their requirement. [ABSTRACT FROM AUTHOR]

In current offshore wind turbine designs, many are basic concepts using standard land-based wind turbines ‘marinised’ using a platform from the offshore oil and gas industry with additional anti-corrosion and structural stiffness. These projects are also focused on fixed offshore wind turbines at depths of less than 50 m. The design conservatism observed is present to avoid many changes to the proven technology on land-based wind turbines and offshore fixed foundations, to assure technical feasibility and economic viability in the short term. However, exportation of onshore technology directly to the offshore environment may not be entirely advantageous. There are opportunities in new designs or configurations, which can potentially lower cost of energy in a less restrictive offshore environment. This paper aims to review the current offshore wind technology and discusses comprehensively some of the factors and opportunities in selecting a downwind configuration for offshore wind turbines. In addition, current industry, research and developmental trends for downwind offshore wind turbines are described. Various technical challenges and gaps foreseen for this design motivation are also highlighted in the paper. [ABSTRACT FROM AUTHOR]

Wind energy has played an increasingly vital role in renewable power generation, driving the need for more cost-effective wind energy solutions. Health monitoring of turbines could provide a variety of economic and other benefits to aid in wind growth. A number of commercial and research health monitoring systems have been implemented for wind turbines. This paper surveys these systems, providing an analysis of the current state of turbine health monitoring and the challenges associated with monitoring each of the major turbine components. This paper also contextualizes the survey with the various potential benefits of health monitoring for turbines. [ABSTRACT FROM AUTHOR]

Wind energy is an important contributor of modern power systems as a renewable energy source. However, wind energy poses new challenges because of its unique characteristics, such as limited predictability, short-term and long-term variability and close-to-zero marginal cost. This paper puts forward the critical aspects of wind energy systems in respect to the transformation of the power system into a “smart grid”. Issues discussed include the electro-mechanical matters like the selection of wind turbine technology, the structure of wind system, the robustness of mechanical parts (gear box and blades) and fault diagnosis. In addition, the system operational challenges such as complexity, instability, unbalance loading, grid interactive problems and impact of wind energy on power system are discussed in this paper. Moreover, the economical subjects such as investment costs and energy management, communication requirements, and security are involved as important titles. Finally, environmental aspects of wind energy are also highlighted to show that the wind energy is an environmentally friendly energy source since it is sustainable, clean and safe. [ABSTRACT FROM AUTHOR]

Renewable energy becomes an asset to the world׳s energy resource for its eco-friendly and low cost energy production feature. As an important renewable energy source, wind turbine technology has become a significant contributor to the world energy production because of its feasible production cost, reliability and efficiency. Researchers are very active to optimize the effectiveness of wind turbines which may lead to increase the productivity of this source of energy. Vibration in the wind turbine system affects the productivity and thus reduces efficiency. Vibration of a system cannot be destroyed but can be reduced or converted to energy using appropriate strategies. Vibration control system improves structural response of wind turbines and reliability which has impact on lifetime of the components. Lowering the vibration amplitude of a system will provide a lesser amount of noise, assure user and operating comport, maintain the high performance and production efficiency. These will assist the system to prolong the lifetime of an industrial structure or machinery. Also vibration control enhances the performance of wind turbines providing suitable work environment without external disturbance. This paper presents an ample review on performance enhancement of the wind turbines by vibration mitigation. The aim of this review is to provide a concise point for researchers to assess the current trend to control vibration of wind turbines technology. This paper will focus on main vibration control techniques of wind turbine structures. It provides the applications of passive, active and semi-active and vibration control strategies for structures, especially for wind turbines. Besides, this paper reviews on damping devices needed for vibration mitigation of structures. These damping devices have been implemented extensively in wind turbines for increasing their efficiency by mitigating vibration. This paper also reviews and assesses the performance of different control policies to control the system input and power input of damping devices. [ABSTRACT FROM AUTHOR]

Given the abundant availability of resources, the market potential, and their cost competitiveness, onshore wind farms and photovoltaic units are expected to drive the overall growth of renewable energy sources in the next decade. However, Europe is a small and densely populated continent, which results in many countries experiencing a severe shortage of suitable land sites for installing new wind and photovoltaic facilities. This, combined with the fact that many existing wind turbines and photovoltaic units reach the end of their operational lifetime, has laid the groundwork for 'repowering'. Repowering includes upgrading or retrofitting renewable energy sources' components and exploits existing land sites, in which renewables are operating for years. This paper intends to emphasise the multiple dimensions of repowering, also delving in its surrounding socio-economic context in various European countries, to identify its barriers and allies as well as gather best practices and lessons learnt from its implementation. Considering data availability, extent of spatial use and bulk equipment, and consequent attention in literature and practice, the analysis mainly orbits around repowering of wind projects, rather than solar photovoltaics. Finally, the paper presents key directions toward wider future exploitation of repowering. • Land scarcity problem with high renewable energy potential addressed by repowering. • In-depth socio-economic extensions of repowering are discussed. • Semi-quantified evaluation highlighting main implementation pillars of repowering. • Best practices and lessons learnt from the implementation of repowering. • Legislative barriers against the wider implementation of repowering. [ABSTRACT FROM AUTHOR]

Wind power is one of the main sources of renewable energy. New applications of this technology are currently under development through small vertical axis wind turbines, allowing energy production in small spaces even at low wind speeds. Therefore, creating an effective turbine design methodology tailored to these operating conditions has been the subject of extensive research. The Savonius-type vertical axis wind turbine is one of the most widely used due to its low cost and easy manufacturing. Several works have examined the effect of various geometric parameters on the performance of the Savonius-type wind turbine. However, there are no published overarching conclusions about these works. Thus, this paper aims to review and discuss in a concise way experiments and simulations carried out by several authors evaluating the effect of some geometric parameters on the maximum power and torque coefficient of Savonius vertical axis wind turbines. The paper also discusses additional experiments that should be performed in future work. • The effect of geometrical parameters of Savonius-type vertical axis wind turbine rotor on its efficiency is reviewed. • Power and torque coefficients response to variation of four geometrical parameters are discussed. • Geometrical parameters as aspect ratio, twist angle, overlap ratio, number of blades, and number of stages are explored. • Diverse experimental and numerical researches are explored and maximum power and torque coefficients found are graphically presented as function of each geometrical parameter. [ABSTRACT FROM AUTHOR]

Wind energy is rapidly growing in recent years. Among different types of wind turbines, due to several advantages, permanent magnet synchronous generator (PMSG) is attractive concept. Since the penetration level of wind power in the grid is increased, therefore, wind power can influence to the grid and vice versa. Some of the important problems in the grid are fault condition and voltage sags. These conditions may affect the operation of wind turbine. In order to enhance low voltage ride through (LVRT) capability in PMSG-based wind turbines, various approaches have been proposed in the last years. In this paper, the review and comparison of several LVRT capability enhancement methods is performed. The two foremost types of LVRT capability enhancement methods are external devices based methods and modified controller based methods. The main objectives of this paper are to introduce performances of different LVRT capability enhancement methods and use of some LVRT capability enhancement methods in PMSG based wind turbine which are applied in other kind of wind power generators. The external devices based methods can be effective but some of these methods are of significant cost. According to the literatures, modified controller based methods can reduce the LVRT capability enhancement cost. Several modified controller based methods have been proposed for LVRT capability enhancement. To compare the mentioned methods, several simulations are performed in MATLAB software. From the review of simulation results, series connection of FACTS devices and modification of back-to-back converter controllers are the highly efficient LVRT capability enhancement approaches. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of Chinese wind power firms have been going international in search of global market for development channels. By employing qualitative research and case study methods, this paper examines the export scale and markets of China’s wind turbines, the market entry modes and location choices of China’s outward foreign direct investment (FDI) in the wind power sector, identifies the determinants and prospects of Chinese wind firms’ internationalization, as well as provides policy implications. It is found that Chinese wind power firms has chosen to internationalize very differently from the Uppsala model in that the exports and FDI of Chinese wind power firms both took place around 2008, and the exports and FDI of Chinese wind power firms are closely linked. The determinants of Chinese wind firms’ internationalization are the competitive advantages of leading Chinese wind firms and the intensified domestic market competition, followed by Chinese government support for internationalization and the attractive overseas market. The prospects of Chinese wind firms’ internationalization are bright but challenging. Drawn on this analysis, conclusions and three policy implications are provided at the end of the paper. This paper contributes to the study of China’s wind power sector from a new perspective. [ABSTRACT FROM AUTHOR]

Wind energy continues to stand out as a more established and mature technology to offset a large proportion of power. Efforts aimed at improving wind energy use to meet the energy demand in turbulent urban wind environment have been the main technical focus. In previous studies on wind resource and behavior in urban environment, different designs of horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) have been reviewed. This paper vividly captures the fact that wind resource has a great potential to be fully explored and developed in the urban environment. Varying ways of application and application techniques being applied for electrical generation, ventilation and pollution dispersion, onshore cooling and dehumidification of coastal urban cities, and economics and environmental benefits of applying wind energy in urban environments are summarized. Although many new ideas and solutions that factor technical, economical and environmental sustainability in urban areas are coming up every day, challenges in design are gradually being solved to take advantage of urban low and turbulent wind speed characteristics, installation space challenges, vibration and noise reduction, among others. Some of the unique solutions that have been and are being developed in the applications of wind energy technology in urban environments are also reported in this paper. [ABSTRACT FROM AUTHOR]

Using floating platforms to support offshore wind turbines will be necessary for many countries to reach their Net-Zero targets, since much of the wind resource is located at water depths at which fixed offshore wind turbines are uneconomic or technologically unfeasible. However, floating platforms for wind turbines are still at an early stage of development, and there are a wide range of platform designs. This paper reviews the current state-of-the-art of floating offshore wind turbine platform designs which currently have or have previously had a prototype, demonstration, or farm scale project at sea. The most common design goals for the platforms and the corresponding design features of platforms used to achieve those goals are reviewed. Past, current and projected future levelized cost of energy values for floating offshore wind are reviewed and discussed. The development of each platform design is described, including evolving design goals and resulting changes in platform features. Finally, overall trends in platform designs are discussed and divided into three phases, defined by changing goals: (i) influences from the offshore oil and gas industry, (ii) specialization to floating offshore wind, and (iii) further specialization to local environment. [Display omitted] • Floating offshore wind turbine platform designs with a device at sea are reviewed. • Common design goals and associated design features of platforms are summarized. • Levelized cost of energy for floating offshore wind turbines is discussed. • Evolution and trends in design drivers and platform designs are summarized. [ABSTRACT FROM AUTHOR]

Abstract Subsynchronous control interaction (SSCI) associated with wind farms has become one of the major challenges for maintaining the stability and reliability of modern power systems. SSCI is mainly caused by the active participation of fast-acting wind turbine converter (WTC) controls in the phenomenon. It can damage the system equipment, reduce the amount of power generation, and degrade the power quality. Thus, it is urgent to develop practical mitigation techniques for the SSCI in order to achieve a smooth and reliable operation of grid interfaced wind farms. This study presents an overview of potential SSCI mitigation techniques at various stages of the power system, including system planning, operation, control, and protection phases at both network and generation sides. In particular, this paper reviews the active damping controls utilizing flexible ac transmission systems (FACTS) and WTC controls. Finally, it outlines the challenges and future work in studying SSCI mitigation techniques in practical wind power systems. Highlights • SSCI mitigation techniques: planning, operation, control and protection stages. • Review of active damping control techniques in network and generation sides. • Challenges and limitations of various SSCI mitigation techniques are discussed. • WTC control modifications and shunt-VSC using filters are recommended approaches. [ABSTRACT FROM AUTHOR]

Abstract This paper evaluates the potential for co-location of offshore wind turbines at sites being developed for tidal stream arrays as a method for reducing the cost of electricity. It is shown that for a typical tidal site, MeyGen in the Pentland Firth, UK, increasing the wind turbine capacity reduces the cost of electricity compared to operating tidal stream arrays alone. This is due to increased energy yield combined with reduction of capital expenditure based on the use of common grid connection and shared support structures. Assessment is made using tidal, wave and wind resource data for a three year period. The overturning moment about the base of a monopile supporting a wind turbine with two tidal turbines is only 8% larger than for a wind turbine alone in a strong current typical of tidal farms. The increased cost of infrastructure is small relative to the increased energy yield and for all array configurations of practical interest, the levelised capital cost of energy is estimated to be 10–12% less from a co-located farm than from a tidal turbine farm alone. Highlights • Cost of electricity by co-locating wind turbines with tidal stream arrays is evaluated. • Energy yield and peak loads are modelled for array layouts in the Pentland Firth. • Peak loads for a shared support are 60% greater than typical offshore wind turbines. • For the same cost, co-location generates 20% more yield than tidal-only arrays. • Co-location offers 10–12% lower levelised cost compared to a comparable tidal array. [ABSTRACT FROM AUTHOR]

Abstract Offshore wind is a source of clean, renewable energy of great potential value to the power industry in the context of a low carbon society. Rapid development of offshore wind energy depends on a good understanding of technical issues related to offshore wind turbines, which is spurring ongoing research and development programmes. Foundations of offshore wind turbines present one of the main challenges in offshore wind turbine design. This paper reviews the present state of knowledge concerning geotechnical and structural issues affecting foundation types under consideration for the support structures of offshore wind turbines, and provides recommendations for future research and development. Highlights • Reviews the technology development and designs of offshore wind turbine foundations. • Discusses geotechnical and structural issues affecting the foundations. • Provides recommendations for future R&D to improve the effectiveness of different designs. [ABSTRACT FROM AUTHOR]

The most important single event of the last years in wind energy technology is the reduction in the cost of producing wind electricity offshore, a reduction that can reach 75%, depending on the system boundary considered, for installations commissioned by 2024. Surprisingly, there is very little scientific literature showing how this reduction is being achieved. The objective of this paper is to analyse the evidence behind cost reduction in one of the most significant cost elements of offshore wind farms, the installation of foundations and turbines. This cost is directly dependent on the daily rates of the installation vessels and on the days it takes to install those wind farm elements. Therefore, we collected installation data from 87 wind farms installed from 2000 to 2017, to establish the exact time for installation in each. The results show that advances have reached 70% reduction in installation times throughout the period for the whole set, turbine plus foundation. Most of these improvements (and the corresponding impact in reducing costs) relate to the larger size of turbines installed nowadays. There is, therefore, not any leap forward in the installation process, but only incremental improvements applied to turbines that are now four times as large as in 2000. [ABSTRACT FROM AUTHOR]

With the unprecedented growth in recent voltage source converter-based high voltage direct current (VSC-HVDC) integrated offshore wind power plants, frequency regulation of onshore systems and their stability has been crucial. Offshore wind farms cannot directly provide frequency support to the onshore AC grid as back-to-back converters in variable speed wind turbines and HVDC grid decouple the two ending terminals. It prevents the kinetic and electrostatic energy from mitigating the frequency transients in the onshore AC grid. Low inertia contributes to an increase in the rate of change of frequency with a further decrease in frequency nadir that undermines the onshore AC system's reliability. However, variable speed wind turbines and voltage source converter stations with appropriate control strategies can efficiently participate in the onshore AC grid's frequency regulation. This paper provides an in-depth review of the frequency support strategies for offshore wind power plants and the voltage source converter stations in a multi-terminal HVDC system, including a comparison of the related approaches and the potential gaps present in the existing literature. This paper also provides guidelines and serves as a reference for researchers focused on the frequency support strategies for such an integrated system. • A comprehensive review on power system frequency regulation through VSWTs and VSC stations is presented. • SFD occurs during rotor speed recovery if no other power is available to compensate for power shortage at that moment. • Use of ESS could be a viable alternative to compensate for the energy shortage during rotor speed recovery. • AFC-based coordinated control in VSC-HVDC is the preferred practicing technology due to its simplicity and robustness. • New protocols need to be defined to cyber secure the offshore wind power plant-based power systems. [ABSTRACT FROM AUTHOR]

Rapidly increasing demand for electricity, rising costs of fossil fuels, and growing environmental concerns are driving research into alternative energy sources. Wind energy has experienced significant growth in recent years. Extensive research has been conducted to efficiently generate electricity from wind energy. However, due to limitations such as space and maintenance, it is very difficult and unsafe to install wind turbines for research and educational purposes. A lab-scale wind turbine emulator has many advantages, including independence from prevailing wind conditions, a greater degree of control, and freedom from space constraints. In this article, authors have reviewed and analyzed over 140 technical articles related to wind turbine emulators. It provides comprehensive information on prime movers, generators, and controls used in wind turbine emulator (WTE) research. Additionally, this paper discusses the strengths and weaknesses of various WTE prime movers, generators, and control algorithms used in the literature review. This article will serve as a good reference for the researchers to choose the right technique for WTE according to their needs. [Display omitted] • Overview of the importance of Wind Turbine Emulators (WTE) in wind energy research. • Comparison of different types of wind turbine emulators. • Discussion of recent advances in wind turbine emulation technology. • Analysis of the current state of wind turbine emulation research. [ABSTRACT FROM AUTHOR]

The present review paper provides a comprehensive overview of the research activities on wind turbine aeroacoustics at DTU over the last 20 years, as well as it gives the state-of-the-art of noise prediction models for wind turbines under complex inflow conditions. Various noise generation models developed at DTU are described and analyzed, including models based on the acoustic analogy, flow-acoustics splitting techniques, Amiet's model, and various engineering models. Some of the models are coupled to existing aero-elastic software and computational fluid mechanics models developed at DTU, and implemented in the simulation platform WindSTAR (Wind turbine Simulation Tool for AeRodynamic noise). This simulation platform consists of WindSTAR-Gen, dealing with models for generation of noise and design of low-noise wind turbines, and WindSTAR-Pro, which is developed to handle the modeling of long distance acoustic propagation. As specific features of the WindSTAR-Pro package, the rotation of the noise sources is modeled, the propagation simulations combine the so-called Parabolic Equations (PE) propagation model with numerical flow simulations to take into account effects from wind turbine wakes, atmospheric turbulence and wind shear. [ABSTRACT FROM AUTHOR]

In recent years, international working groups, mainly from the International Electrotechnical Commission (IEC) and the Western Electricity Coordinating Council (WECC), have made a major effort to develop generic —also known as simplified or standard— dynamic wind turbine models to be used for power system stability analysis. These models are required by power system operators to conduct the planning and operation activities of their networks since the use of detailed manufacturer models is not practical. This paper presents a comprehensive review of the work done in this field, based on the results obtained by IEC and WECC working groups in the course of their research, which have motivated the publication of the IEC 61400-27 in February 2015. The final published versions of the generic models developed according to the existing four wind turbine technology types are detailed, highlighting the subsequent changes made during the development phase. The main differences between IEC and WECC generic models are also analyzed. Not only is the final model structure presented but we also provide a complete description of the physical behavior of wind turbines facing power system stability problems. Results are thus of great interest to grid operators, software developers, wind farm owners and researchers focused on the integration of wind energy into power systems. [ABSTRACT FROM AUTHOR]

Congestion management is imperative for reliable and secure system operation in restructured power systems. Since the installation of wind farms at proper locations offers the possibility of congestion relief, this paper investigates congestion management in power systems with specific consideration of wind energy sources. The optimal location of a wind farm is determined by the Bus Sensitivity Factor and the Wind Availability Factor. Differential Evolution is a population-based heuristics algorithm used for solving non-linear optimization problems. We propose an Improved Differential Evolution based approach to ease congestion in transmission lines by generator rescheduling and installation of new wind farms. In this approach, an enhanced mutation operator is introduced to improve the performance of the Differential Evolution algorithm. A standard IEEE-30 bus system is used to evaluate the proposed algorithm under critical line outages. The simulation results show that the proposed approach is more effective than other approaches. [ABSTRACT FROM AUTHOR]

The subsynchronous control interaction (SSCI) occurs when the wind turbine converter (WTC) controls interact with the series-compensated or weak AC network. The mechanism and attributes of the emerging interaction phenomenon invilving wind turbine generators (WTGs) are quite different from the traditional subsynchronous resonance or oscillation (SSR/SSO) phenomenon in steam turbine-generators (STGs). The SSCI is characterized by various system-wide parameters, including the wind speed and its uneven distribution in a wind power plant, varying number of WTGs connected to the grid, type of the WTGs, parameters of the WTC controls, level of series compensation, stiffness of the grid, etc. Such system-wide parameters change over time and thus make the modeling and analysis rather challenging to conduct SSCI studies. An ideal modeling approach for the SSCI is expected to preserve the system topology as well as valid for a wide range of operating conditions and parameters of the system. On the other hand, an ideal stability analysis method is supposed to give key quantitative information, such as the magnitude, frequency, and origin of the oscillation, as well as the component level participation indices. This paper provides a comparative insight into the application of existing and emerging modeling and stability analysis approaches for SSCI investigations in large-scale wind farms. It highlights the strengths and weaknesses of various modeling methods and analysis criteria. Finally, the paper underlines the recent advancements and points out towards the research directions in small/large-signal impedance modeling and stability approaches for accurate and quantitative investigation of the SSCI. • SSCI is a system-wide phenomenon thus the modeling and analysis is challenging. • Strengths and weaknesses of the existing modeling and stability analysis methods in the time and frequency-domain are discussed. • An modeling method should preserve system topology and remains valid under a wide range of operating conditions. • An ideal stability analysis method should give key quantitative information: magnitude, frequency and source. [ABSTRACT FROM AUTHOR]

The wind farm development is very slow in the developing countries particularly in the Middle East. This is attributed to many factors including economy of these countries which is mainly rely on fossil fuels and hence yields to low cost of energy, political and technological barriers, lack of wind potential studies or lack of high wind regions and more. This paper attempts to address these issues and foresees opportunities for developing household or small communities wind farms which can be rely on individual or small communities’ funds as well as creating job opportunities for them. As the case study, the province of Sistan-Baluchestan in Iran is considered to study how the economy of local communities or households can be strengthen by exploring small wind turbine developments for them. An economic and statistical analysis is conducted based on wind data for cities of Chabahar, Dehak, and Dalgan in the province. Wind energy characteristics and patterns are extensively explored for these cities from 473,040 wind data samples. This is resulted in the average annual wind power density of 181 W / m 2 , 158 W / m 2 , and 146 W / m 2 , for Chabahar, Dalgan, and Dehak, respectively at the height of 40 m. By considering five different commercial wind turbines, from 1.6 to 30 kW capacities, the total annual electrical power production, profits and payback time for each wind turbine is presented. It is concluded that nearly 90,000 households can benefit from profit of annual energy production of 225 GWh. [ABSTRACT FROM AUTHOR]

A minor deviation in wind speed causes large deviation in the output power of wind turbine because of cubic bond association between these two parameters. Therefore, a precise assessment of wind resource over any site is considered of paramount significance. The investigations associated with the wind resource assessment have been proved of immense help for installation of different wind energy technologies such as nano, micro, small, medium, and large scale for wind energy generation. In order to provide a detailed information regarding the research in wind resource assessment a comprehensive literature review encompassing the different techniques, methodologies involved in development of wind power projects, and uncertainties associated with wind resource assessment as well as the preliminary assessment methodologies have been presented in this work. The advanced computational models namely wind atlas analysis and program, WindPro, computational fluid dynamics, and geographical information system are most frequently used software tools for mapping, modelling and annual energy estimation for a single or multiple wind turbines by considering the local conditions such as topography, surrounding obstacles, orography, and surface roughness based on the on-site measurements for a particular site. In addition, the statistical methods for short and long term data analysis, vertical wind speed profile, numerical weather prediction models, optimization of existing wind resource, and scope of hybrid wind energy systems have been delineated in this paper. Furthermore, current review presents a complete approach with reference to all the facets of the present status of research in the area of wind resource assessment worldwide. [ABSTRACT FROM AUTHOR]

In Italy, wind solutions for the generation of electricity from renewable energy sources (RES-E) have been widely adopted, especially in regions with good geo-climatic conditions. In the last years, the need to limit the soil sealing has resulted in a great deal of attention being given to the implementation of RES-E energy policies integrated with the existing urban properties. In this paper, the authors have pursued two main objectives. The first is an analysis of the financial feasibility resulting from the realization of roof-top wind turbines in the city of Bari (Southern Italy). This analysis was carried out through the application of a GIS-based decision support model. The second aim deals with the explanation of the mathematical relation between the aerodynamic parameters and the economic variables of the investment. The expressions obtained, on the one hand, allow to enucleate the actual influence of the aerodynamic parameters on the economic variables and to verify the empirical coherence of the outputs; while on the other, they provide algorithms for the rapid assessment of the performance indicators of the investment. The methodology developed identifies an easily repeatable operative and logical path, which can also be used in other territorial contexts. [ABSTRACT FROM AUTHOR]

Recently, floating offshore wind turbines (FOWTs) have attracted increasing attention owing to their capabilities, and such devices are being considered the next-generation technology to develop green energy. However, despite their prominent benefits, FOWTs are vulnerable to damage and degradation due to frequent operation under harsh environments involving highly variable wind flows and incident waves. In such scenarios, the system dynamics tend to generate additional motions, workloads, and undesired fluctuations. Owing to these aspects, the optimization of control strategies is challenging and thus must be extensively investigated to ensure long-term survivability. Many approaches involving both simulations and experiments on small-scaled test rigs have been reported. In this regard, this paper highlights the encountered issues and reviews the state-of-the-art control technologies for FOWTs, with the classifications based on the enhancements in the typical methods and floater architectures under region 3 (high wind speed) conditions. • Outlined potentials and challenges associated with floating offshore wind turbines. • Classification based on enhancement in key methodologies and properties of floaters. • Control strategies arranged and compared from simple to modern and advanced control algorithms. • Presentation of enumerated tables with evaluated criteria for suitable decisions of methods. • Comparisons about influences of controller parameters on the system performance. [ABSTRACT FROM AUTHOR]

China is the largest power producer and consumer and has the largest installed capacity of wind turbines (WTs) worldwide. In the last two decades, China's installed capacity of WTs has exploded, significantly impacting its wind power (WP) industry and promoting the development of the industry globally. This paper examines China as one part of the world and elucidates its role, status, and impact on global WP development from a global perspective. Research indicates that China has become the global leader in WP, its WP development has greatly promoted the growth rate of global WP, and it has become an indispensable force in global WP development. However, the comprehensive capability of China's WP generation is not only lower than that of other major WP countries but also lower than the global average. China's WTs have low global recognition and are difficult to export. In addition, the proportion of WP in China's power structure is lower than that of most other major WP countries. Fortunately, these gaps between China and other major WP countries are gradually narrowing. The goal of this paper is to help researchers and investors better understand China's situation and to provide a reference for the rational investment in and development of China's WP. • China has become a global wind power leader, but only in the installed capacity. • China's wind turbines have low recognition in global, and difficult to export. • Comprehensive capability of China's wind power is lower than that of global average. • Currently, China's wind power mainly wins in terms of quantity rather than quality. [ABSTRACT FROM AUTHOR]

Wind power curves play important roles in wind power forecasting, wind turbine condition monitoring, estimation of wind energy potential and wind turbine selection. In practice, it is a challenging task to produce reliable wind power curves from raw wind data due to the presence of outliers formed in unexpected conditions, e.g., wind curtailment and blade damage. This paper comprehensively reviews wind power curve modeling techniques from the perspective of modeling processes, i.e., wind data analyses, wind data preprocessing and various wind power curve models. Moreover, the performances of many popular power curve models are studied in different seasons and different wind farms. The results show that no universal wind power curve model can always perform better than other models under any environmental conditions. In general, there are three factors that affect the final wind power curves: data filtering approaches; wind power curve models; and choice of optimization strategies (especially the method applied to construct objective functions). However, there is no guarantee that all outliers will be removed from the raw wind data. Consequently, designing robust regression models or constructing robust objective functions may be two effective ways to obtain accurate power curves in the presence of outliers. The above two strategies depend largely on the error characteristics of power curve modeling. While it is often observed that the error distribution of the power curve modeling may be asymmetric, few researchers have considered this trait when building wind power curves. Therefore, this paper proposes several strategies that focus on designing asymmetric loss functions and developing robust regression models with asymmetric error distributions. Models that benefit from these characteristics may be more suitable for power curve modeling tasks and are more likely to produce better wind power curves. • The different roles of wind power curve models in the utilization of wind energy are reviewed. • The paper discusses the classification of preprocessing approaches for the uncertainties in raw wind data in detail. • The paper provides a comprehensive review of the probabilistic and deterministic wind power curve models. • The performances of many power curve models are comprehensively compared under different environmental conditions. • The asymmetric error characteristic of power curve modeling is analyzed and considered for accuracy improvement. [ABSTRACT FROM AUTHOR]

Operations and maintenance (O&M) is a key contributor to wind farm expenditures. To increase competitiveness, wind farm operators are increasingly looking into leveraging real-time sensor data from condition monitoring (CM) systems. CM provides significant insights on evolving asset failure risks for wind turbines. To date, these insights have not been fully leveraged in wind farm O&M due to ad-hoc connections to decision-making. Specifically, CM applications in wind farms have been limited to detection of turbines with imminent failure risks that require immediate replacement. In reality, wind farm maintenance requires a careful proactive orchestration of O&M dependencies across turbines along with multiple sources of uncertainty associated with asset availability, operational and market conditions. This paper proposes a unified condition-based maintenance and operations scheduling approach for wind farms that models uncertainties related to turbine availability, wind power output and market price. The proposed formulation explicitly considers the turbine-to-turbine dependencies in operations and maintenance, such as opportunistic maintenance, to identify the O&M decisions that are optimal for multiple wind farms. The problem is formulated as a chance-constrained stochastic programming model to maximize operational revenue while ensuring high levels of turbine availability and generation. To make the chance constraints tractable, two approximations are proposed with a focus on sample average approximation (SAA) and prominent tail inequalities such as Markov's inequality and Chernoff bound. Our results on a comprehensive set of experiments demonstrate that the proposed approach provides significant improvements in asset availability, market revenue and maintenance costs in large scale wind farms. • A stochastic condition-based optimization model is proposed for wind farm O&M. • Condition-based chance constraints are formulated to model farm-level availability. • Tractable approximations are developed for the proposed chance constraints. • An extensive experimental framework is built using degradation and operational data. • Proposed model significantly improves availability, revenue and maintenance outcomes. [ABSTRACT FROM AUTHOR]

Floating offshore wind growth places the industry development close to commercial scale. However, the harsh environment with strong winds, waves, and currents, together with the increasing size of wind turbines and floater motions could affect power production and reduce system lifetime due to fatigue loads. In any case, operating the wind turbine close to the optimum efficiency value guaranteeing its reliability through fatigue load reduction could be achieved with a proper control strategy. This paper proposes a critical review of the state-of-art of floating wind turbine control technologies, discussing the advantages and drawbacks of the most used control algorithms and classifying them, to summarize the future trends of the research. • Offshore substructures for wind turbines are explained. • Wind turbine fundamentals are presented. • Wind turbine control influence on a floating system is discussed: Negative damping phenomena. • A comprehensive review of floating wind turbine control technologies and their associated algorithms is provided. • New trends in floating offshore wind turbine control are introduced. [ABSTRACT FROM AUTHOR]

This paper describes the development of a data set mapping all commercial wind turbines in Canada: the 9th largest onshore wind energy fleet in the world. Details contained in the data enable the analysis of the evolution of commercially deployed wind turbines as well as the illustrating the effects of the introduction and cessation of different policies affected historical deployment. In total, over 6700 turbines spanning more than 265 projects and nearly 14.0 GW of generating capacity were indexed including coordinates, model, manufacturer, owner, tower height and commissioning date. Data were compiled from publicly available sources including planning documents, technical reports, environmental impact studies and acoustic emission reports. In 2021, average rotor diameters were 140 m with 108 m tall towers, more than triple the average diameter and double the average tower height from 20 years ago. The analysis of this data found that a typical wind farm in Canada consists of 0.97 turbines/km 2 , while the typical installed capacity density has recently jumped from around 1 to 2.94 MW/km 2 in 2021. Competitive procurement policies have often trended towards larger installed capacities, whereas smaller wind farms emerged more often when policies directed at community ownership were in place. Policies that encouraged local manufacturing developed regional clusters of particular manufacturers, but generally ceased after the local manufacturing policies ended. This work serves as a benchmark for the evolution of wind energy in Canada and a framework for similar data sets in other jurisdictions, and provides a resource for academic researchers, wind farm developers, government bodies and planning agencies as well as the general public. • Details of the Canadian wind fleet database mapping over 6700 individual turbines. • Discussion of the major policies that have influenced the evolution of wind in Canada. • Evolution of wind turbine and wind farm size and capacity density. [ABSTRACT FROM AUTHOR]

Wind turbine (WT) experiments in wind tunnels can benefit the efficient utilization of wind energy in many aspects, such as the testing of new products, the validation of numerical models, and the exploration of underlying mechanisms of WT-induced flow field. However, there is a lack of comprehensive and critical review on this topic. In this paper, necessary pre-experimental works are presented first in terms of the design process of miniature WT, scaling criteria, blockage correction, and devices and methods for measurement. In addition, the wind tunnel tests on flat and complex terrains are discussed for in-depth understanding. The dynamic wake behaviors in both near wake and far wake are reviewed with the clarification of two hypotheses of wake meandering. Careful microsite selections of WTs on complex terrain can be beneficial for the total power yields. Furthermore, special attention is paid to active yaw control to verify the potential to increase power output while mitigating structural loads. Finally, discussion on research limitations and prospects are given as avenues for future research. This study provides a comprehensive overview and in-depth discussion on WT experiments in wind tunnels, which is expected to facilitate the solution of theoretical problems in wind energy and enable more practical research. • Experimental setup of wind tunnel tests for wind turbines are reviewed. • Dynamic flow in near wake and far wake is discussed with theoretical analysis. • Typical terrain models and terrain effects on wind turbine performance are discussed. • The underlying physics and effect of active yaw control are experimentally verified. • Research challenges and prospects are summarized. [ABSTRACT FROM AUTHOR]

In this paper, the wind energy potential of Vesleskarvet in Antarctica is assessed and the possibility of meeting the energy needs of South African׳s SANAE IV located in Vesleskarvet using the wind resource of the site is presented. The data used for the study consists of daily average wind speed, temperature and atmospheric pressure collected over a period of eleven years (2001–2012) at an anemometer height of 10 m. The data is obtained from South African Weather Services and the analysis is performed using statistical approach. Some commercially available wind turbine ranging from 10 kW to 1650 kW are simulated using HOMER simulation software in different scenario to determine the combination of wind turbine, battery and power electronic converter that could meet the electrical energy demand of SANAE IV with lowest Net Present Cost ( NPC ) and the Cost of Energy ( COE ) over 25 year life cycle of the project. The results show that Vesleskarvet has exceptional wind resource with average wind speed of 10.9 m/s and standard deviation of 6.3 m/s. The minimum wind speed in the period under study is 0 m/s and maximum value of 41.9 m/s. The average wind potential density (2001–2001) is 1650 W/m 2 . The HOMER optimization result reveals that 15 numbers of PGE20/25 wind turbine with rated power of 25 kW, hub height of 25 m, cut in wind speed of 3.5 m/s, rated wind speed of 9 m/s and cut-out wind speed of 25 m/s seems suitable to meet the electrical energy demand of SANAE IV with NPC of $1,336,262, operating cost of $976,500 and COE of $0.102. [ABSTRACT FROM AUTHOR]

We investigate the importance of taking the spatial interaction of turbines inside a wind park into account for power forecasting. This paper provides two tests that check for spatial interdependence such as wake effects. Those effects are suspected to have a negative influence on wind power production. After that, we introduce a new modeling approach that is based on the generalized wind power prediction tool (GWPPT) and therefore respect both-sided censoring of the data. The new model makes use of a spatial lag model (SLM) specification and allows for random effects in the panel data. Finally, we provide a short empirical study that compares the forecasting accuracy of our model to the established models WPPT, GWPPT, and the naïve persistence predictor. We show that our new model provides significantly better forecasts than the established models. [ABSTRACT FROM AUTHOR]

Due to atmospheric pollution from fossil fuels, the reduction of wind turbine costs, and the rise of the low-carbon economy, wind energy conversion systems have become one of the most significant forms of new energy in China. Therefore, to reduce investment risk and maximize profits, it is necessary to assess wind resources before building large wind farms. This paper develops a comprehensive system containing four steps to evaluate the potential of wind resources at two sites in Xilin Gol League and at additional two sites in Alxa League of Inner Mongolia, China: (1) By calculating the total scores of three indexes, including the effective wind power density (EWPD), wind available time (WAT) and population density (PD), an indexes method is applied to assess the theoretical wind energy potential from 2001 to 2010. (2) To judge the fluctuations in the wind speed, the Fisher optimal partition method and the Jonckheere–Terpstra test are used to analyze the changes in the average monthly and yearly wind speeds from 2001 to 2010. (3) Three probability density functions, i.e., Weibull, Gamma and Lognormal, are used to assess the wind speed frequency distribution in 2010. To enhance the evaluation accuracy, three intelligent optimization parameter estimation algorithms, i.e., the particle swarm optimization algorithm (PSO), differential evolution algorithm (DE) and ant colony algorithm (ACO), are used to estimate the parameters of these distributions. (4) It is helpful to analyze the wind characteristics when assessing wind resources and selecting wind turbines. Therefore, the optimal frequency distribution based on the best parameter estimation method can be chosen to calculate the wind power density, the most probable wind speed and the wind speed carrying the maximum energy. The experimental results show that Site 1 and Site 4 are more suitable for large wind farms than Site 2 or Site 3. [ABSTRACT FROM AUTHOR]

To achieve the Net-Zero Emissions goal by 2050, a major upscale in green hydrogen needs to be achieved; this will also facilitate use of renewable electricity as a source of decarbonised fuel in hard-to-abate sectors such as industry and transport. Nearly 80% of the world's offshore wind resource is in waters deeper than 60 m, where bottom-fixed wind turbines are not feasible. This creates a significant opportunity to couple the high capacity factor floating offshore wind and green hydrogen. In this paper we consider dedicated large-scale floating offshore wind farms for hydrogen production with three coupling typologies; (i) centralised onshore electrolysis, (ii) decentralised offshore electrolysis, and (iii) centralised offshore electrolysis. The typology design is based on variables including for: electrolyser technology; floating wind platform; and energy transmission vector (electrical power or offshore hydrogen pipelines). Offshore hydrogen pipelines are assessed as economical for large and distant farms. The decentralised offshore typology, employing a semi-submersible platform could accommodate a proton exchange membrane electrolyser on deck; this would negate the need for an additional separate structure or hydrogen export compression and enhance dynamic operational ability. It is flexible; if one electrolyser (or turbine) fails, hydrogen production can easily continue on the other turbines. It also facilities flexibility in further expansion as it is very much a modular system. Alternatively, less complexity is associated with the centralised offshore typology, which may employ the electrolysis facility on a separate offshore platform and be associated with a farm of spar-buoy platforms in significant water depth locations. [Display omitted] • Offshore hydrogen pipelines are economical for large and distant farms. • Decentralised offshore typology is flexible in operation and facilitates expansion. • Commercial electrolysers need no pre-requisite modifications on a floating turbine. • Centralised offshore typology is preferable for large deep-water farms. [ABSTRACT FROM AUTHOR]

In recent years, wind energy utilization has become increasingly attractive on economic grounds. Wind turbines for electricity generation employ a proven technology, supply energy on a reliable and sustainable basis, and at good, windy sites may even be competitive with conventional sources of energy. In this paper, the statistical results are reported of an investigation of the potential of wind energy as a power source for the Iranian northwestern cities of Tabriz and Ardabil. A number of different methods were explored as well. In this study, the Weibull probability distribution function is employed using mean meteorological wind data measured at three-hour intervals. These data have been measured at a height of 10 m above ground level and gathered over a six-year period. Furthermore, the hourly, diurnal, seasonal, monthly, and annual wind speed variations are analyzed and the economics of the wind turbines is evaluated. The yearly values of the Weibull shape parameter vary from 1.81 to 2.13 m/s with a mean of 1.99 m/s for Tabriz and from 2.62 to 2.98 m/s with a mean of 2.86 m/s for Ardabil. Also, yearly values of the Weibull scale parameter vary from 3.35 to 4.45 m/s with a mean of 4.18 m/s for Tabriz and from 3.68 to 4.55 m/s with a mean of 4.16 m/s for Ardabil. The results show that the highest wind power potential occurs during months of August and July in Tabriz and during months of October and September in Ardabil. The results indicate that the monthly mean price of electricity generated from the 25 kW wind turbine in Tabriz and Ardabil, for most of the months of the year, are less than or approximately equivalent to the current purchase tariff of renewable energy in Iran. [ABSTRACT FROM AUTHOR]

To reduce the release of CO 2 from traditional energy, wind energy is developed very fast all over the world. This means that more large wind turbines will be installed on land and more environmental impacts will be created from wind turbines. Noise generated from rotating wind turbines in wind farm propagates through a complex flow-field including a varying atmospheric flow and varying wakes created by the wind turbines, which can greatly influence the sound propagation. This paper presents a new multi-fidelity flow-acoustics simulation framework to predict the sound propagation in both near and far fields of wind turbines in wind farm, which has the potential for wind farm application with good accuracy and acceptable computing time (i.e. 8 min with 6 CPUs for the centre frequencies between 20 Hz and 1000 Hz in 1/3 octave bands). The new multi-fidelity flow-acoustics simulation framework (named WindSTAR) consists of a three-dimensional wind farm engineering flow model, an engineering sound source model, and a high-fidelity sound propagation model. To validate the new framework, a comprehensive measurement strategy was designed and performed to measure simultaneously the turbine operations, inflow conditions, wake flow fields and acoustic fields from near to far fields of a 3.9/4.1 MW SGRE wind turbine in Drantum, Denmark. Comparisons between measurements and computations in various flow conditions from stable to unstable atmospheres show good agreements with an averaged absolute difference of 0.8 dBA. Based on its good accuracy and acceptable computational efficiency, the new multi-fidelity framework is able to be used for designing and controlling wind farms. • A new multi-fidelity flow-acoustics simulation framework is developed. • A new 3D engineering wind farm flow model is developed for studying sound propagation. • A comprehensive flow-acoustic measurement is done for a 3.9/4.1 MW wind turbine. • Validations against measurement show good agreement in stable, neutral and unstable atmospheric flows. • The framework has potential for use in wind farm design and control application. [ABSTRACT FROM AUTHOR]

Understanding the spatial variation of the levelised cost of energy (LCOE) of offshore wind is fundamental for identifying potential areas for the development of this technology. With this in view, this paper presents a large-scale mapping of the LCOE of floating offshore wind over the European Atlantic, with a focus on floating semi-submersible platforms. The energy production is estimated accurately at every site using hindcast wind data combined with the power curve of an exemplar wind turbine. Furthermore, this work presents an analysis of the different costs incurred in the lifetime of the project using expressions depending on site-specific variables, i.e., water depth and distance to shore. The results highlight the paramount influence of the energy production and, therefore, the wind resource on the final cost of energy. The lowest LCOE values (∼95 €/MWh) correspond to the areas where the wind resource is most abundant: off Great Britain and Ireland, in the North Sea and off NW Spain. The influence of the resource leads inevitably to LCOE values somewhat higher off Portugal and Norway (∼125 €/MWh), and much higher in the Gulf of Biscay and south of the Iberian Peninsula (>160 €/MWh). Within regions with a similar resource, e.g., the North Sea (LCOE in the range 95–135 €/MWh), the distance to shore is found to be the main variable affecting the LCOE. By comparison, the costs related to water depth (primarily, mooring costs) are of little significance – unlike with bottom-fixed technologies. • Levelised cost of energy (LCOE) from floating offshore wind off Atlantic Europe. • LCOE mapping with cost breakdown and accurate estimation of electricity output. • LCOE values depend mostly on wind resource, followed by distance to shore. • The highest LCOE values (above 160€/MWh) occur in the Gulfs of Biscay and Cadiz. • The lowest LCOE values (around 95€/MWh) occur off UK, Ireland and NW Spain. [ABSTRACT FROM AUTHOR]

There has been a dramatic increase in wind power supply due to the growing demand for renewable energy sources across the globe. In this process, technological advancements have led to the emergence of more sophisticated wind turbines with higher hubs and larger swept areas to reduce the unit costs for power generation. However, there is also a growing concern about the visibility impacts of wind turbines. Spatial modelling of the potential visibility of wind turbines holds strategic information for wind power siting decisions. The visibility information is critical to breaking trade-offs between energy production and protecting the visual amenity of landscapes. Currently, public attention to the visual impacts of wind turbines tends to rise in countries with high wind power capacities. Decreases in property values due to wind turbine visibility and negative impacts on scenery are among the factors that draw public attention. These implications make it necessary to use spatial analysis and develop mitigation strategies based on the geospatial outputs. This paper aims to produce Potential Visibility Models (PVM) to analyse wind turbine visibility from candidate observation locations where the scenery is an important asset. These are residential buildings (RB), protected areas (PA), natural and archaeological sites (NAS), tourism development centres (TDC), roads (RD), and the coastal areas (CS). The results showed that potential turbine visibility varied across the study area considering the five qualitative visibility classes. The areas with "very low" and "low" potential visibility were proposed as candidate areas of low visual impact for wind power generation. [Display omitted] • Potential visibility models (PVM) for wind turbines were produced. • The observer locations were selected in the areas where scenery is the key asset. • Target offsets that represent turbine heights ranged from 20 to 140 m. • Potential wind turbine visibility was conceptualized in a "combined visibility" map. • The areas of lower potential visibility scores were proposed for wind power siting. [ABSTRACT FROM AUTHOR]

In order to mitigate global climate change and air pollution, the Chinese government has assigned high priority to expanding low-carbon power generation in China. Recent studies have shown that wind power is one of the most promising renewable energy option in China. Although many studies have estimated the generation potential of onshore wind power, their results vary widely from 1783 TWh to 39,000 TWh. Therefore, we examine the different assumptions in these papers and identify three main factors influencing the results. The three influencing factors are: weather data set, land utilisation factor, and wind turbine configuration. For our model-based analysis, we define a reference scenario which is used to compare the results. Our analysis shows using a different weather data set increases the generation potential to roughly 35,000 TWh. This is 54% higher than the generation potential of the reference scenario. The land utilisation factor also has a large influence, ranging between −10% and −51%. The studies' assumptions and data should be subjected to careful scrutiny, as the calculated wind power potentials are widely used to develop decarbonisation strategies for the energy system. • Study results on wind power potentials in China vary from 1783 TWh to 39,000 TWh • Influencing factors: weather data set, land utilisation, and wind turbine configuration. • Model-based sensitivity analysis with nine scenario settings. • Chosen weather data set has the highest impact on the calculated results with a variation of 54%. [ABSTRACT FROM AUTHOR]

Wind energy takes an important role in the transformation of the global energy system towards clean and sustainable sources. The main development of wind energy technology in recent decades is the growth of wind turbine size motivated by economic factors. The larger turbine size helps increase power output and energy efficiency, however, it leads to challenges in wind turbine operation and maintenance. To further reduce the cost of wind energy, advanced control approaches are developed focusing on power maximization, structural load mitigation, lifetime extension, and reliability improvement. This multi-objective problem is difficult to solve due to design conflicts. The optimal trade-off between goals is varying and depends on actual operating situations such as on-site wind characteristics, system aging, and grid requirements. Modern utility-scale wind turbines are equipped with numerous sensors providing useful information about turbine components' operation status. With the development of computation capability and big data analytics techniques, the turbine performance and state-of-health (SoH) information could be obtained and evaluated through historical logged data using Prognostics and Health Management (PHM) systems. This information aids the optimal operation and maintenance of wind energy systems. The health state of a system has significant effects on its performance, reliability, and remaining useful life. So it is crucial to consider SoH when designing controllers for optimal operations. In recent years, the integration of SoH information into the closed-loop control system has begun to attract the attention of the wind energy researcher community. Controllers have been adapted based on current and future aging behaviors optimizing the trade-off between service life expansion and power production maximization. This paper provides a review of integrated prognostics and health management control (IPHMC) systems for the optimal operation and maintenance of wind turbines and wind farms reducing the cost of wind energy. The review focuses on the combination of real-time PHM and advanced control for wind turbines. The most recent developments, generalization, classification, and comparison of IPHMC approaches for wind energy systems are given. Integrated PHM control concept has the potential to improve the reliability of wind turbines, however, further research on real-time RUL prognostic and reliability evaluation techniques is required for the effective implementation of the concept. • Generalization, classification, and comparison of the IPHMC concept applied for wind turbines are realized. • The concept of integrating PHM and control can optimize the trade-off between power and load reduction. • The reliability characteristic or lifetime of wind turbines can be controlled using the IPHMC concept. • Further research on real-time RUL prognostic and reliability evaluation techniques is required for applying IPHMC. [ABSTRACT FROM AUTHOR]

Recent years have seen an unprecedented growth in the use of sensor data to guide wind farm operations and maintenance. Emerging sensor-driven approaches typically focus on optimal maintenance procedures for single turbine systems, or model multiple turbines in wind farms as single component entities. In reality, turbines are composed of multiple components that dynamically interact throughout their lifetime. These interactions are central for realistic assessment and control of turbine failure risks. In this paper, an integrated framework that combines i) real-time degradation models used for predicting remaining life distribution of each component, with ii) mixed integer optimization models and solution algorithms used for identifying optimal wind farm maintenance and operations is proposed. Maintenance decisions identify optimal times to repair every component, which in turn, determine the failure risk of the turbines. More specifically, optimization models that characterize a turbine's failure time as the first time that one of its constituent components fail - a systems reliability concept called competing risk is developed. The resulting turbine failures impact the optimization of wind farm operations and revenue. Extensive experiments conducted for multiple wind farms with 300 wind turbines - 1200 components - showcases the performance of the proposed framework over conventional methods. • A condition-based maintenance and operations model is proposed for wind farms. • Component and turbine dependencies on failure risks and maintenance are modeled. • A tailored solution algorithm is proposed to ensure computational scalability. • A comprehensive experimental framework is developed via degradation and wind data. • The proposed approach provides significant improvements over benchmark models. [ABSTRACT FROM AUTHOR]

Various wind resource assessment (WRA) methods have been applied to explore the feasibility of installing wind turbines for urban wind energy harvest. Nevertheless, there are only limited computational fluid dynamics (CFD) studies available to consider WRA around high-rise buildings in realistic urbanized areas. This paper presents a numerical assessment of urban wind energy potential, specifically pursuing to overcome the limitations of former studies by addressing the following points: i) conducting a large-scale wind power estimation by employing the meticulous topography in realistic compact high-rise urban area; ii) validating CFD simulations with the on-site measurements in two seasons; iii) obtaining the annual mean wind speed, wind power density and turbulence intensity between the existing high-rise building features, including building geometry, roof geometry, presence or absence of upstream obstacles, arrangements of integrated building complex and parallel high-rise buildings; iv) investigating the local installation locations of wind turbines and the distances from rooftop sidewalls or lowest mounting heights above rooftops with high power densities and acceptable turbulence intensities for wind energy harvest. The results of this wind resource assessment suggest an effective strategy of turbine installation for implementing urban wind power potential in a realistic compact high-rise urban area. • A large-scale wind power estimation is implemented in realistic high-rise urban areas. • Impacts of existing high-rise building features on wind power are analyzed. • Accuracy of CFD simulations are validated by on-site measurements in two seasons. • Effective strategy of turbine installation is considered for high-rise buildings. [ABSTRACT FROM AUTHOR]

The mass roll out of solar PV across the Global South has enabled electricity access for millions of people. In the right context, Small Wind Turbines (SWTs) can be complementary, offering the potential to generate at times of low solar resource (night, monsoon season, winter, etc.) and increasing the proportion of the total energy system that can be manufactured locally. However, many contextual factors critically affect the viability of the technology, such as the extreme variability in the wind resource itself and the local availability of technical support. Therefore, performing a detailed market analysis in each new context is much more important. The Wind Empowerment Market Assessment Methodology (WEMAM) is a multi-scalar, transdisciplinary methodology for identifying the niche contexts where small wind can make a valuable contribution to rural electrification. This paper aims to inform the development of WEMAM with a critical review of existing market assessment methodologies. By breaking down WEMAM into its component parts, reflecting upon its practical applications to date and drawing upon insights from the literature, opportunities where it could continue to evolve are highlighted. Key opportunities include shifting the focus towards development outcomes; creating community archetypes; localised studies in high potential regions; scenario modelling and MCDA ranking of proposed interventions; participatory market mapping; and applying socio-technical transitions theory to understand how the small wind niche can break through into the mainstream. • Small scale wind power requires a detailed market assessment. • WEMAM is a multi-scalar, transdisciplinary methodology designed for small wind. • A review of market assessment literature highlights new techniques. • Reflections on the implementations of WEMAM to date guide its evolution. [ABSTRACT FROM AUTHOR]

Wind energy as one of the renewable energies is serving as an indispensable role in generating new electric power. The worldwide installation of wind farms has considerably increased recently. To extract more wind resources, multi-megawatt wind turbines are usually designed and constructed with large rotors and slender tower. These flexible structures are susceptible to external dynamic excitations such as wind, wave and seismic loads. The excessive vibrations can compromise the wind energy conversion, lead to the structural fatigue damage and even result in the catastrophic failure of wind turbines in harsh environmental conditions. Various control devices have been proposed and used to mitigate the unwanted vibrations of wind turbines to enhance their safety and serviceability. This paper aims to provide a state-of-the-art review of the current vibration control techniques and their applications to wind turbines. Firstly, the widely used control strategies in engineering structures are briefly introduced. Their applications to suppress the adverse vibrations of the structural components of wind turbines, mainly the tower and blades, are then reviewed and discussed in detail. It can be concluded that the vibration mitigation of wind turbines is very challenging due to the fact that the dynamic behaviours of wind turbines are very complicated, which are associated with the aerodynamics, rotation of the blades, interaction between the tower and rotating blades, and soil-structure interaction, etc. Moreover, it is a challenge to straightforwardly use many of the conventional control devices because of the limited spaces in the tower and blades. • The commonly used control approaches in wind turbines are briefly presented. • The applications and control effectiveness of various control devices used in wind turbines are comprehensively reviewed. • The remaining challenges of the conventional control methods in wind turbines are discussed. [ABSTRACT FROM AUTHOR]