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This is a discussion on the paper titled “Assessing feed-in tariffs on wind power installation and industry development in Taiwan” published by Hsu et al. In the discussed paper, there were several missing variables in the historical test of the system dynamics (SD) model, and thus the test was not integrated and valid. Additionally, the simulated results of the missing variables were used as important indexes to observe the behavior of the SD model. Therefore, it was highly likely that the solution and related policy analysis based on the simulated results were incorrect. Accordingly, the present study illustrated the structure characteristics of the SD model with respect to the fore-mentioned problems, discussed the reason for missing variables and proposed a method to assess whether or not the historical test was integrated. Finally, after a careful analysis, this study offered suggestions to perfect the historical test proposed in the discussed paper. [ABSTRACT FROM AUTHOR]

The African continent is endowed with massive energy resources such as hydropower, solar, wind, natural gas, wave energy, and many more, yet it is the continent with the least energy supply in the world thereby resulting in a lack of sufficient energy to meet its growing energy demand. Though the continent holds 100 GW of wind capabilities, the current installed capacity as at 2018 was 5.7 GW with countries in northern Africa as well as South Africa capturing over 90% of the wind energy share on the continent. Therefore, this paper reviews the wind energy industry in Africa by identifying the current installed and potential capacity of wind energy on the continent. The challenges faced by the wind energy industry such as policy, competition, technical and economic are also reviewed. Transitions, technological innovation systems, and strategic niche management theoretical sustainability transition framework as well as proposed pathways to overcome these prevailing challenges hindering the full exploration of the wind energy sector in Africa are also highlighted in order to uplift the continent's socio-economic status. Basically, this can be achieved through the adoption of strong 'political-will' by African national governments to drive wind energy development. There is also the need for institutional frameworks to ensure the practical adoption of new wind energy technologies. Furthermore, the major benefits Africa stands to gain from investment in wind energy are enumerated by comparing with the benefits realized by other countries' economies as a result of investing in the wind energy industry. For instance, cheap electricity, job creation, industrial growth, and eco-friendly energy source. • Reviewing wind energy industry in Africa and existing challenges. • The challenges faced by African's wind energy industry can be categorized under policy, competition, technical and economic. • Framework for transiting Africa's wind energy industry from small-scale production to large-scale commercial industry.. [ABSTRACT FROM AUTHOR]

Pakistan is among the 10 countries that face the worst energy crisis of the world. As the country struggles with a number of financial, political and social issues, the transition from a conventional fuels based economy to a green economy is not an easy one. Pakistan has been blessed with immense potential of clean renewable sources of solar, wind and biomass but they have not been exploited yet. Renewable energy technology sector has not penetrated the energy mix and is currently an emerging market. This paper highlights the steps the country has taken in the past and the steps that are being taken at present to emerge out of the prevailing energy crisis when even the most urban areas suffer from power outages of 12 h per day. Until 2009, no single grid interconnected wind farm existed but now the situation has changed considerably and wind farms contributing to the national grid are a reality now. Three grid interconnected farms have been inaugurated and many others are in pipeline. The national policy regarding wind power systems has recently changed after unexpected setbacks to ongoing projects. This paper reviews the developments in the wind power sector of the country and lists some suggestions that can help improve the wind power penetration in the national energy mix. [ABSTRACT FROM AUTHOR]

Since 2010 China has faced a worrying phenomenon “wind curtailment” in the development and operation of the wind power industry. This phenomenon has resulted in sharp decline of the utilization hours of the wind power equipment, seriously affected the economic benefits of the wind farms and caused serious energy waste. The wind curtailment in China is seemingly caused by the volatility of the wind power technical characteristics. However, judging from a deep level, the planning, networking management and policies play a critical role. With analysis this paper makes such a conclusion: it is not practical to solve the wind curtailment of China solely with the technical solutions and comprehensive measures must be taken. The paper offers strategies from the planning, policy and technical levels to solve the wind curtailment problem according to the actual situation of China and by referring to experiences of developed countries. [ABSTRACT FROM AUTHOR]

Development of alternative energy sources has become a necessity as fossil energy resources are declining. At the same time, energy demand is rapidly increasing, putting the world on the verge of a global energy crisis. Moreover, the extensive use of conventional energy sources is polluting the environment and causing global warming. On the other hand, wind and other renewable energy sources are viable and clean alternatives to fossil fuels. Low operating cost and extensive availability make wind one of the most advantageous and effective renewable energy sources. This paper provides an exposure to the necessity for deployment of renewable energy sources and the worldwide installed capacity of wind power as well as a review of various wind technologies in conjunction with their applications and devices of operation. Furthermore, this paper discusses the cost of electric generation in wind power plants as well as the economic and environmental policies that advocate the installation of wind energy systems. [ABSTRACT FROM AUTHOR]

This paper is an enquiry into the role of State policies in influencing wind installed capacity. The paper studies the impact of policies on deployment of wind potential across the States of India over two decades. Aggregate indices are computed for each of the seven wind resourceful States of India indicating attractiveness for installed capacity of wind energy. For computing the indices, four policies, Feed-in-Tariff, Renewable Purchase Obligation, Banking facility, and Wheeling charges are considered. Panel data techniques are then employed to investigate the impact of the policy differences on wind potential deployment over the 19 year period (1993–2012) after controlling for three State-specific factors. The controlling factors include per-capita income of the State, power deficit, and ratio of installed capacity of wind to geographic potential indicating unmet capacity. The results show that that policy index positively impacts wind deployment whether control variables are included or not. Moreover, the control factors like the per-capita income of the State and unmet capacity have positive influence over the investment in wind energy. [ABSTRACT FROM AUTHOR]

Pakistan is facing increasing power shortage from the last two decades. The Government of Pakistan (GoP) has taken various remedial measures and is offering incentives for private investment to generate electricity at cheap rates. New hydropower dams were proposed in the past, such as Kalabagh Dam, but could not be commissioned to date. Fossil fuels are depleting and oil has to be imported for oil-fired power plants, which is highly expensive and a burden for the country's economy. This scenario has raised serious concerns among citizens. In this frustrating situation, there is dire need for exploration and installation of alternate renewable energy resources, in particular, wind energy and solar energy to augment the existing power generation and distribution apparatus. These then need to be integrated with the national power grid. Pakistan has enormous wind energy potential, especially in three of its four provinces namely, Khyber Pakhtun Khwa (KPK), Sindh and Balochistan. The country's multifarious terrain includes coastal and hilly areas suitable for installation of large wind turbines. The GoP has taken active steps towards measuring wind speed statistics in various parts of the country. In this paper, the authors analyze wind speed data for the mentioned three provinces. The fourth province, Punjab, has very limited wind energy potential and hence is not considered. Wind speed data for Jiwani (a reference site in Balochistan) was obtained from Pakistan Meteorological Department (PMD) as a case study. The paper attempts to assess how much wind energy can be harnessed from the three provinces. It then focuses on Jiwani whose specific power density is estimated for wind turbine sizing. Lastly, a practical scheme is proposed for integration of wind power output (from windy sites) with the national power grid. [ABSTRACT FROM AUTHOR]

With a coastline of more than 3000 km and its location in the monsoonal climate zone, Vietnam is expected to have good potential for wind energy development. During the last years, several preliminary studies on assessment of wind energy potential in Vietnam have been carried out. Policies for supporting wind energy projects are still under development and improvement. The goal of this paper is to give an overview on wind energy potential and the current application as well as development of wind energy in Vietnam. This paper also presents the current policies for wind energy development and identifies the major barriers need to be addressed for the future development of wind energy in Vietnam. [ABSTRACT FROM AUTHOR]

This paper aims to present a review of the increasing contribution of wind power to the Brazilian electric matrix and an analysis of the main impact on technical, political and social aspects. This work takes into account the state-of-art of the wind power technology, the wind resource potential and the evolution of installed capacity in the country. The institutional programs and the fiscal incentives provided by the Brazilian government are also discussed in this paper, including its impacts on the society. We have reviewed national and international reports and relevant scientific papers to realize this work. The analysis shows that electric crisis in 2001 led the Brazilian government to develop new energy policies that supported the rapid growth of the wind industry from imported technology. Later on in the year 2004, the government mandated that the technology be developed within the country. It is expected that from 2011 (of approximately 1500 MW) until 2021 the installed wind capacity would increase by a factor of 600%. However, the national technology acquisition and development is still incipient. It is important to produce locally wind turbine components and is highly desirable to increase collaboration between industries and universities in the country. [ABSTRACT FROM AUTHOR]

This paper presents survey about Fault Ride Through (FRT) techniques and controllers which employed with all wind generation system types. After presenting a comprehensive FRT survey, paper proposes three Fault Ride Through (FRT) controllers for keeping stability of Fixed Speed Wind Generation (FSWG) system serving in isolated Micro-Grid (MG). The first controller has been implemented by inserting Superconductor Fault Current Limiter (SFCL) in series with wind generator terminals during fault instant. The second proposed FRT controller is modifying the conventional Pitch Angle Controllers (PAC) to can spill and reduce high percentage of extracted mechanical wind power during and subsequent fault occurrence which in turns help stability improvement and restoration. Third FRT technique is performed by adapting the wind turbine gearbox ratio which forces the wind generation system to run far from the maximum power point. The best performance is obtained with the SFCL controller. Superior results are obtained when the three proposed FRT controllers are employed simultaneously. The three developed FRT controllers are simple, reliable and economical attractive. Effects of fault type on SFCL FRT controller performance are analyzed and investigated in details. The proposed SFCL FRT controller has been tested under single phase, double phase, phase to phase, and three phases to ground faults. Results display that the three phases to ground fault is the most severe type on SFCL FRT performance from stability point of view. On the other hand, double phase to ground fault is the most severe one from fluctuations and oscillations points of view. Parameters of the SFCL must be adjusted based on the three phases to ground fault. If the SFCL FRT controller is designed to can deal with three phases fault, it sure can deal with the other fault types successfully. [ABSTRACT FROM AUTHOR]

In the United Kingdom wind power is recognised as the main source of renewable energy to achieve the European Union 2020 renewable energy targets. Currently over 50% of renewable power is generated from onshore wind with a large number of offshore wind projects in development. Recently the government has re-iterated its commitment to offshore wind power and has announced that offshore wind subsidies are to increase from £135/MWh to £140/MWh until 2019. This paper provides a detailed overview of the offshore wind power industry in the United Kingdom in terms of market growth, policy development and offshore wind farm costs. The paper clearly shows that the United Kingdom is the world leader for installed offshore wind power capacity as pro-active policies and procedures have made it the most attractive location to develop offshore wind farm arrays. The key finding is that the United Kingdom has the potential to continue to lead the world in offshore wind power as it has over 48 GW of offshore wind power projects at different stages of operation and development. The growth of offshore wind power in the United Kingdom has seen offshore wind farm costs rise and level off at approximately £3 million/MW, which are higher than onshore wind costs at £1.5-2 million/MW. Considering the recent increase in offshore wind power subsidies and plans for 48 GW of offshore wind power could see more offshore wind power becoming increasingly financially competitive with onshore wind power. Therefore offshore wind power is likely to become a significant source of electricity in the United Kingdom beyond 2020. [ABSTRACT FROM AUTHOR]

This paper presents a new speed-sensorless control strategy for a stand-alone doubly-fed induction generator supplying energy to an isolated load. The method is based on the root mean square (rms) detection scheme. The generated stator voltage is controlled via rotor currents. Amplitude of stator voltage and its frequency are controlled simultaneously. The output signals from the voltage controllers are the reference signals for the rotor current amplitude and frequency of the stator voltage is regulated with the help of frequency control loop. This developed direct voltage control method is applicable for both the balanced and unbalanced load and also for standalone and grid connected mode. The control pulses for the rotor side converter is supplied by the hysteresis controller which is operated on the error signal calculated between actual and reference rotor currents. This paper also provides the brief idea about the voltage and frequency control on modern Autonomous DFIG based Wind Energy Systems via single phase mathematical model of standalone DFIG system. A short state-of-the-art review on mechanical position/speed sensorless control schemes for autonomous DFIG based WESs is presented, which helps the present researcher and students working in this area. These include stator flux oriented control techniques; direct voltage control techniques; MARS observer based techniques for autonomous DFIG-based variable-speed WESs. Simulation results obtained from a 2MVA DFIG system, prototype in MATLab/Simulink, are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

Multi-criteria decision making (MCDM) methods are becoming increasingly popular in solving energy selection problems because these problems involve multiple and often conflicting criteria. This paper presents comparative analysis of ranking renewable energy sources (RES) for electricity generation in Taiwan using four MCDM methods - WSM, VIKOR, TOPSIS, and ELECTRE. The Shannon entropy weight method is used to assess the importance of each criterion for the ranking of RES. After that, four MCDM methods are utilized for quantitative evaluation to rank all available RE alternatives. From the weights estimation results, efficiency is the first priority in all evaluation criteria, followed by job creation, operation, and maintenance cost. The purpose of this study is to rank the priorities of various RES and propose recommendations for Taiwan's RE development. The ranking results show that hydro is the best alternative in Taiwan, followed by solar, wind, biomass and geothermal. Furthermore, sensitivity analysis of the weights was conducted considering the ranking results heavily depend on the criteria weight. The results of sensitivity analysis indicated that when financial or technical aspects are focused upon, hydropower is the best RES because its technology is the most mature and the cost is the lowest in Taiwan. In addition, from an environmental perspective, wind energy is the best choice, and from the social perspective, solar PV is the best choice. The findings of this study can provide useful information to energy decision makers and serve as a reference for Taiwan's energy policy. [ABSTRACT FROM AUTHOR]

Acceptance plays an important role in the successful adoption of wind energy technology. This article identifies factors influencing the acceptance of wind energy and selects those factors which have the highest relevance for wind energy acceptance in Bavaria. We decided to analyze the Federal State of Bavaria in Germany as its current policy governance decelerates the building-up of wind turbines in this federal state. Using a qualitative approach, the results indicate that the perception of political processes, such as the recent enacting of the 10-H regulation in Bavaria, influences the acceptance towards wind energy, as trust and transparency in political processes are essential. In addition, the paper reveals the importance of the distributive justice, focusing in particular on the subitem envy, which can be considered on a neighboring or regional level. Additionally it reveals additional factors which are relevant for wind energy acceptance in the specific case of the analyzed federal state. [ABSTRACT FROM AUTHOR]

The ocean is a huge energy conversion field, and ocean renewable energy (ORE) can provide us with a constant source of energy. Research on ORE collection and utilization has been emerging in recent years, and the number of ORE research results has been increasing. This paper visualizes the trends and current research status of ORE by performing bibliometric analysis using VOSviewer and CiteSpace. The results are analyzed in terms of annual publications, countries, institutions, authors, journals, keywords, topics, and references. The results indicate that current research hotspots include (1) theoretical calculations and simulation modeling, (2) design of ocean renewable energy devices (OREDs), (3) deployment of OREDs and optimization improvements, and (4) evaluation of ORE projects. Wave energy harvesting applications, offshore wind energy harvesting applications, design and improvement of triboelectric nanogenerator, and artificial reefs or islands are the frontiers of research in the field of ORE. With the development of energy conversion technologies, the future of ocean power generation will have a promising and attractive prospect. The results of the study provide a comprehensive overview of the evolution of research hotspots in this field and can help those researchers willing to work in this research area to quickly understand the research frontiers and the general situation. • Retrieved 3231 articles published over 10 years in the WOS core collection database. • Highlight top contributors, organizations, hot spots and research frontiers. • Classify key research topics and determine the knowledge structure related to marine renewable energy. • Looking for research frontiers and hotspots of marine renewable energy. • Evaluate research in this area and identify potential or possible future research areas. [ABSTRACT FROM AUTHOR]

The Jiangsu coastal area in China has rich wind resources, but is relatively backward in economic development and faces the dual constraints of conventional energy and environment. Therefore, seizing the opportunity provided by the “National Strategy” and promoting the development of a wind-industry cluster are of great importance to this area. First, this research has demonstrated that the Jiangsu coastal wind-power cluster is characterized by local government leadership through a depiction of its current status. Secondly, this research has analyzed the competitive advantage of the Jiangsu coastal wind-power cluster. It has pointed out that excessive intervention by the local government, development issues with wind-power component enterprises, insufficient independent technology innovation, and an imperfect cluster development environment have hindered healthy cluster development. A series of appropriate strategies are then proposed. This paper could not only help policy-makers and the industry understand how to achieve sound development of the Jiangsu coastal wind-power cluster, but also could provide a useful reference for researchers intending to explore wind-power cluster development in the rest of the world. [ABSTRACT FROM AUTHOR]

Historically, every form of large scale power production in Sweden has given rise to organised, sustained and partly successful resistance motivated by environmental arguments. Since wind power is identified by the Swedish Parliament as an important energy source for the future and the wind power industry is expected to expand on a large scale, there is reason to believe that the already existing environmental opposition to wind power will continue to grow and will attempt to limit or at least partly obstruct the wind power expansion. In order to facilitate an understanding of this opposition and its possibility to significantly influence future wind power expansion in Sweden, this paper draws upon previous research on the opposition towards hydropower, nuclear power and biomass in Sweden, and discusses these findings in relation to previous research on wind power opposition. [ABSTRACT FROM AUTHOR]

In recent years, the Malaysian government has attempted to develop renewable energy (RE) through newly introduced regulatory supports after 30 years of failure to achieve a greater than one percent non-hydroelectric RE share in the total power mix. The government is currently assessing the onshore wind energy potential in Malaysia to determine the possibility of including wind energy in its FiT scheme. However, wind energy development in this low-energy location is not as straightforward as it would seem. Many previous wind studies in Malaysia have relied on poor data and simplistic or inadequate methodologies, resulting in grossly inaccurate estimates of wind potential. Moreover, two wind turbine generator demonstration projects executed by the government have failed. However, above all, the greatest factor impairing the progress of RE development in Malaysia is the weak and uncertain political support of these efforts. This lack of robust support is particularly true where fossil fuels are still heavily subsidised amid the subsidy reform in 2013. A review of global wind energy development shows that successful projects depend heavily on a sound and robust regulatory framework supported by strong and consistent political will. This dependence is not observed in Malaysia, where the government continues to subsidise private independent fossil fuel power producers but levies taxes on electricity consumers to fund RE development. These levies do not effectively support RE development, given the magnitude of the RE fund compared to fossil fuel subsidies. In the absence of strong and sincere political will, the progress of RE development in Malaysia has been notably slow. As a result, the prospect of wind energy development in Malaysia currently remains vague. This paper discusses the above issues in detail and recommends selected regulatory mechanisms based on the global experience of supporting RE development in Malaysia. [ABSTRACT FROM AUTHOR]

The “Hydrogen Office building (HO)” presents a wind–hydrogen energy system, located in Fife/Scotland, which has been set-up to demonstrate the role of hydrogen in reducing the impact of wind intermittency in a grid-tied microgrid. The main components of the system are a wind turbine, alkaline electrolyser, hydrogen storage and a PEM fuel cell. The building demand is met by the wind turbine, while the fuel cell provides back-up power to the ground floor when wind power is unable to meet the demand. Accurate modelling of wind–hydrogen systems allows their successful implementation and operation, however, most of the currently available simulation tools do not provide consistent methods to represent the dynamic behaviour of such systems which is essential for their precise design, control, performance optimisation and economic study. Previous research lacks global methodologies for a whole-system scope simulation. Moreover, experimental validation is missing in most of these models and no guidelines are given for parameter estimation, which are essential for replicability. This paper presents a comprehensive methodology for the modelling, simulation and performance evaluation of wind–hydrogen systems, while including experimental validation and guidelines for parameters estimation. The developed model encompasses usability, adaptability, dominant dynamics accuracy and reliability that makes it able to assess different systems prior and after their installation. The proposed model has succeeded to depict the HO dynamic behaviour accurately with an error of less than 2% in average. The model has also been successfully utilised to evaluate the HO system performance. Evaluation criteria includes: average energy production, stand-alone operation and round-trip efficiency among others. Quantitative analysis has showed how this methodology can contribute to improve the design and performance of such systems. [ABSTRACT FROM AUTHOR]

With the rapid development of human society, the demand for energy has accordingly increased, and along with this increasingly serious energy and environmental crises have developed. Many countries have been focusing on new energy resources to combat these crises, and offshore wind energy resources are especially attractive; they are safe, non-polluting, renewable, and widely distributed with large reserves, which has made them become the focus of developed countries. However, the distribution of wind energy has strong regional and seasonal differences, which determines the success and efficiency of wind energy developments. Therefore, there is a clear need for “resource evaluation and planning in advance” in the wind energy development. Previous research has made a great contribution to the evaluation of offshore wind energy resources, mostly through analysis of the climatic characteristics of wind energy. In the actual development process of wind energy resources, these analyses of the climatic characteristics of wind energy provide a reference for site selection. However, after constructing wind farms, to aid their operation, there needs to be a more comprehensive understanding of other factors, such as the short-term forecasting and medium- to long-term predictions of wind energy. This paper reviews the research progress of the wind energy resource evaluations, and then considers where future research needs to focus, for the evaluation of wind energy resources. This mainly includes further analyses of the climatic characteristics of wind energy, short-term forecasting, medium- to long-term predictions, early disaster warning systems, the establishment of a wind energy development index (WEDI) and an integrated application system, in hope of providing a reference for offshore wind power generation, seawater desalination and other wind energy resource developments, and accelerating the industrialization and utilization of offshore wind energy. Doing this will alleviate the energy and environmental crises, and promote the sustainable development of human society. [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]

Wind power generation has increased rapidly in China over the last decade. In this paper the authors present an extensive survey on the status and development of wind power generation in China. The wind resource distributions in China are presented and assessed, and the 10 GW-scale wind power generation bases are introduced in details. The domestic research status of main components of WP system is then elaborated, followed by an evaluation of the wind power equipment manufacturers. Finally, the outlook for the development of the wind power utilization in China is presented. [ABSTRACT FROM AUTHOR]

The goal of carbon neutrality provides a new opportunity for the development of renewable energy, especially for wind power. In this paper, 11 regional climate models (RCMs) including CORDEX-EA and PRECIS at two different resolutions are used to evaluate the performance in simulating the spatio-temporal characteristics for wind speed and energy potential from 1981 to 2005. The results show that most models can reproduce the spatio-temporal patterns, and the simulation of the eastern region is better than that of the western region. Besides, most of the higher-resolution models had better simulation performance for spatial-temporal patterns and inter-annual variation. Then, the weighted multi-model ensemble is used to project the changes of the wind speed and the wind power density over China's mainland during the mid-21st century under the RCP8.5 scenario. In future, a decrease in wind speed is projected by most RCMs over China, although some regions, such as the southern parts of China, are projected to have more wind energy potential. The percentage variation of annual mean wind speed will remain in the range of ±4%. The wind power density will decrease in the north and the largest decrease will be found in the northwest. However, the annual mean wind power density in the southeast China will have an increase of 2.21% in the middle of this century. The inter-annual variation of the wind power density in most regions will increase by more than 20%. However, intra-annual variation in the wind power density is likely to decrease in most regions of China, ranging from about −20% to −50%. • A weighted multi-model ensemble was used to project the changes of wind power density over China. • The changes of annual mean wind power density vary in different sub-regions of China, ranging from −3.21% to 2.21%. • The inter-annual variation of the WPD in most regions will increase by more than 20%. [ABSTRACT FROM AUTHOR]

As wind power resources are abundant, China’s wind power industry has entered a period of rapid growth since 2005, and constantly facing new challenges at the same time. In this paper, the general situation of China’s wind power resource and wind power industry development are introduced. On this basis, future development potential and target of wind power industry are analyzed combining with the recent introduction of the policy and the “Twelfth Five-Year Plan”. The main obstacles prevailing in the development such as grid integration, price mechanism, industry standard system, and supporting policies are discussed. In addition, strategy advice for promoting the further development of China’s wind power is proposed. In general, the development prospect of China’s wind power industry will be even brighter. [ABSTRACT FROM AUTHOR]

Fast depleting fossil fuels and the growing awareness for environmental protection have led us to the energy crisis. Hence, efforts are being made by researchers to investigate new ways to extract energy from renewable sources. ‘Microgrids’ with Distributed Generators (DG) are being implemented with renewable energy systems. Optimization methods justify the cost of investment of a microgrid by enabling economic and reliable utilization of the resources. This paper strives to bring to light the concept of Hybrid Renewable Energy Systems (HRES) and state of art application of optimization tools and techniques to microgrids, integrating renewable energies. With an extensive literature survey on HRES, a framework of diverse objectives has been outlined for which optimization approaches were applied to empower the microgrid. A review of modelling and applications of renewable energy generation and storage sources is also presented. [ABSTRACT FROM AUTHOR]

Integrating variable and non-dispatchable renewable power generation into existing power systems will have consequences for their operation and future expansion. These impacts will depend on two factors: (1) the variability of the total renewable power generation on different time scales and (2) the possibilities of accurately forecasting these fluctuations. In this paper, previous research on variability assessment and forecasting of solar, wind, wave and tidal energy resources is reviewed. The aim is to summarize the state of knowledge in each area and to compare the approaches used for the respective resources. For temporal variability, methods and models used for assessing the variability are surveyed, as well as what is known about the variability at individual sites and for larger aggregates of sites. For forecasting, an overview of forecasting methods for the different resources is made, and selected forecasting methods are compared over different time horizons. An important finding is that it is hard to draw strong conclusions from the existing studies due to differences in approaches and presentation of results. There is a need for further, more coherent studies that analyze the variability for the different resources in comparable ways, using data with the same resolution, and for studies that evaluate the smoothing effect and complementarity of combinations of several renewable energy resources. For forecasting, future research should suggest ways to evaluate forecasts from different renewable energy sources in easily comparable ways, using data from the same locations or regions, with the same temporal and spatial resolution, and with comparable metrics for the forecasting errors. [ABSTRACT FROM AUTHOR]

In recent time, the concern for grid integration of wind power has been a subject of discussion in the academic community. At present, the penetration level is still moderate for most grids to accommodate. As the penetration level increases, wind power may cause additional problems to the grid due to its intermittent nature. One of the intending solutions to this problem is the adoption of energy storage. This paper examines the state of the art energy storage technology options that are capable of mitigating wind power intermittency on the grid and their challenges. It also highlighted the existing policies that aided the development of wind power and discusses the limitations of its integration into the grid. It was found that, the ability of storage technology to be effectively utilised in mitigating the wind power intermittency depends on the ramp rate of the technology, response delay time, duration of storage, maturity of technology, installation cost, efficiency of the technology, its environmental impact and the suitability of the site topology. Therefore, no single storage technology is capable of providing total solution at mitigating the effect of wind power intermittency on the grid. The effectiveness of the storage technology lies in the hybridization of the storage technologies depending on the level of cost and technical requirements. [ABSTRACT FROM AUTHOR]

China is the global leader in terms of installed wind capacity. Further, wind energy development is expected for the next years and decades to meet the continuously increasing electricity demand and the need of using clean domestic energy. Since 2009 China is divided into four geographical regions, each assigned with a different benchmark on-grid tariff. Moreover the existing infrastructures are not equally developed throughout the country, making investment decisions more complicated and risky. The scope of this paper is to apply an innovative methodology and evaluate the attractiveness of each region for wind energy development, by taking into consideration all relevant investment risks, such as wind potential, wind curtailment, access to the grid and macroeconomic parameters. To this purpose a Monte Carlo simulation approach, integrated into a typical financial model, is implemented in each of the four regions, performing many hundreds of iterations, each characterized by a randomly selected set of the examined uncertain parameters. This approach intends to provide information to private investors doing a first exploratory research in the huge country׳s area in order to decide whether and where to invest, as well as to policy makers to help them assess critical policy parameters and investigate different scenarios of wind energy development. The evaluation of the current framework for wind energy development in China verifies that the existing system of feed-in tariffs in China is very effective for the balanced deployment of wind energy in the whole country. However, it is shown that the risk of curtailment and grid accessibility may significantly reduce the potential profitability of wind energy investments in all four regions. Priority for development of infrastructures should be given in isolated northern windy areas with high-accumulation of wind farms. [ABSTRACT FROM AUTHOR]

This paper presents a wind-resource atlas of Venezuela based on wind observations recorded from on-site meteorological stations. Meteorological datasets of 32 weather stations located over northern Venezuela are used in the development of the maps of three main regions in Venezuela: West, Central and East. Hourly observations of wind speed and direction at each anemometer mast, recorded during the period 2005–2007, have been analysed in order to define the statistical description of the wind resource in the studied area. This processed data along with information on elevation and roughness length is used to model the horizontal and vertical extrapolation of wind data and the estimation of the wind resource. An implementation of Mass-conservation Wind-Flow Model in OpenWind software is used to calculate the wind resource at each anemometer mast. A distance-squared interpolation method is proposed as the post-processing procedure and blending technique to create each map upon which a Venezuelan wind atlas is then built. Simulation results include two main wind-resource atlases obtained at 80 m height above ground: (i) a traditional map of mean wind speed for each direction; and (ii) a map of power density. Results show that the best wind-energy resources are located in the northern coastal area of Venezuela. [ABSTRACT FROM AUTHOR]

Wind power industry has experienced swift development and gradually moved towards maturity in China. However some hiding issues have appeared and threatened its sustainable development. In this paper, we employ the supply chain framework to present a thorough and comprehensive review on China׳s wind power industry. First we identify key stakeholders along the supply chain and discuss their concerns. Then we summarize the evolution of related policies in both upstream and downstream of the supply chain. The concerns of stakeholders and the existing policies will help understand the progress and challenges of the industry in China. We find that inability of independent technique innovation, unordered and unbalanced pattern of wind farm development, de-motivation of power grid companies, incompatible technical codes of power grid operation, and neglected demand response are among the key issues. Policy recommendations are proposed to address these problems. [ABSTRACT FROM AUTHOR]

In this paper the harmonization of new wind turbine rotor blades development is given as well as the analysis of behavior by verification testing for a wind turbine rotor blade of composite materials. The design, fabrication, the status of wind energy standards and the analysis of behavior by full-scale verification testing for wind turbine rotor blades of composite laminated materials is given, too. The experimental methodology of static, vibratory and fatigue tests for the wind turbine rotor blade of composite laminated materials is presented. These verification tests were performed after the rotor blade development had been completed. The development of the rotor blade was performed using the PC computer with the CATIA designing system and the Gerber Garment cutter system. The blade was fabricated from composite laminated materials. The contour of airfoil was formed by a continuous structural pocket and a fiberglass skin. [ABSTRACT FROM AUTHOR]

This paper contributes to the development of renewable energy innovation metrics through an exploration of innovation patterns across the European countries in 2010. The identified localized innovation capabilities describe the health of the wind, solar and bioenergy sectors, highlighting a concentrated RES innovation activity within four countries: Germany, France, United Kingdom and Denmark. The association of technological capabilities along the innovation composite indicators allows the extraction of useful insights of the role of environmental policies on employment and technological change. Briefly, the corporate research investment per patent is lower for wind energy (EUR 0.61 million) and higher for PV and biofuels (approximately EUR 1 million). Important lever of innovation capabilities across Europe is identified within public support to deployment, which provides significant insights in terms of economic efficiency of generation technologies; the investigation finds job ratios which are higher for wind and lower for PV technology. As the evolution of the market drives the patterns of innovation activities for all selected technologies, considerable financial consequences are identified in the context of delocalization of clean technology manufacturers. [ABSTRACT FROM AUTHOR]

Abstract: Currently, many defects have appeared in wind and solar power generation systems. Utilizing the complementary of wind and solar power generation will break the bottleneck of new energy development. How to select the site of wind/solar hybrid power station scientifically is a primary problem. First, the framework of the indicator system is obtained from the literature review and refined according to the resources evaluation standards and different perspectives of the various scholars. Then this paper selects seven wind/solar hybrid power stations which have been put into operation as the case study, weights the indicators through the method of order relations, and evaluates these seven regions via ELECTRE-II. The conclusions are consistent with the related research findings and have better correctness, proving the feasibility and effectiveness of the method. It may provide some theoretical basis for the macro-site selection of wind/solar hybrid power station. [Copyright &y& Elsevier]

Renewable energy plays a crucial role in both climate change mitigation and adaptation in highly climate-vulnerable nations such as Nepal. This paper reviews various types of renewable energy technologies and their status, potential for adoption, relationship to climate change, and mitigative and adaptive roles in Nepal. Nepal has installed micro-hydro projects, solar power, improved cooking stoves, biogas technology, improved water mills, and wind energy to mitigate and adapt to climate change. There is a growing potential for renewable energy development in Nepal, such as hydropower, solar, wind energy, biogas, and improved cooking stoves. Roughly 70% of Nepal's energy consumption is generated from traditional energy sources while renewable energy accounts for approximately three percent. The gradual increase in the use of renewable energy has reduced greenhouse gas emissions and enhanced carbon sequestration. By adopting renewable energy technologies, Nepal has reduced emissions by 221,129 tCO 2 e from 2017 to 2018. Nepal's second Nationally Determined Contribution targets a 15% increase in national energy use from renewables with a reduction of 23% of CO 2 emissions by 2030 using biogas and improved cooking systems. Furthermore, a significant increase in the adoption of renewable energy has become a pivotal strategy in adaptation to climate change in social, health, and economic sectors resulting in time savings, alternative income sources, improved health and educational status, local job opportunities, and the promotion of social capital. The benefits of adapting to climate change and mitigating CO 2 emissions via renewable energy are significant at the local, national, and international levels. This study recommends that the government of Nepal focus work on energy policy reviews to address local energy demand and climate change issues by utilizing renewable energy resources at the local level, which has global implications. • Suitable, potential renewable energy technologies in Nepal. • The relationship between energy and climate change. • Relevant data on energy and climate change in tables and figures. • Social, economic, and environmental benefits of renewable energy. • Climate change adaptation and mitigation via renewable energy. [ABSTRACT FROM AUTHOR]

As the goal of carbon neutrality has been proposed consecutively, renewable energy sources such as wind, solar, and bioenergy are gaining close attention in national strategic and sustainable development plans. Along with the development of renewable energy generation technologies, it is necessary to assess the environmental burden of renewable energy generation. This study analyzed the economic and environmental benefits of wind power, solar power, and biomass power generation methods over their life cycle. This paper comprehensively assessed and compared their environmental impacts based on a life cycle assessment (LCA) framework combined with ecological footprint analysis for the three renewable energy generation in China, and compared the results with those of thermal power generation to make strategic suggestions for the renewable energy power generation industry. The results show that: (1) wind power consumed the least energy, only 6.80 kJ/kW·h, and had the lowest emissions of CO 2 , SO 2 , NOx and CO and environmental impact potential. (2) Based on the ecological footprint analysis on the provincial level, only Anhui, Shandong and Jiangsu provinces showed ecological deficits, while the other provinces were in ecological surplus, mostly above 50% of their ecological areas. (3) Compared to thermal power generation, which consumed 1170.911 kJ/kW·h, wind power was the only one of the three renewable energy achieved a reduction in energy consumption. Wind power is currently the most efficient way of generating renewable energy. [Display omitted] • The environmental and economic benefits of wind power, solar photovoltaic power, and biomass power generation were assessed. • Life cycle assessment and ecological footprint were used as analytical methods. • Wind power generation is preferred to solar photovoltaic and biomass power generation. • Recommendations for the future development of the renewable energy generation industry are presented. [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]

The high emission of fossil fuels are major driving forces in renewable energy technology development. In response, the lift-type vertical axis wind turbines (VAWT) is experiencing a renewed interest for large-scale offshore wind energy generation and also for small-scale urban devices. Significant research has been published on the aerodynamic design and optimisation of VAWTs. In this paper, an attempt is made to review the aerodynamic design parameters which influence the VAWT's aerodynamic efficiency. Each parameter is discussed in detail regarding their advantages and disadvantages. A baseline VAWT design has been put forward from this literature review to support VAWT aerodynamic analysis. Furthermore, areas of future research requiring attention have been identified to further progress the aerodynamic design and development of VAWTs. • The aerodynamic design parameters which influence the lift-type VAWT are discussed. • Recommendations are made from the review and a baseline VAWT design is outlined. • Design areas requiring research have been identified to progress VAWT technology. [ABSTRACT FROM AUTHOR]

China has become the world's largest clean energy country in terms of the total installation of wind and photovoltaic power and annual newly installed capacity. However, weather conditions render renewable energy unstable, thereby restricting its application to a power grid; reducing the randomness in wind or photovoltaic power is the major challenge of the utilization of solar and wind energy. This paper systematically reviews the explorations and the practices related to wind and photovoltaic power consumption in China. Considering the difference in the methods of supplementing the variable and intermittent output of wind and PV power, five consumption modes are outlined: distributed energy microgrid absorption, power grid peak shaving operation consumption, wind-photovoltaic-storage consumption, wind-photovoltaic-thermal complementation, and wind-photovoltaic-hydro complementation. The theories, features, current situation and growing trends of each mode are analyzed. Finally, several suggestions, including promoting multi-energy complementary microgrid application and installing large-scale pumped storage hydropower, are provided for improving the efficiency of renewable energy development in China. • Practical variable energy consumption modes are outlined and analyzed. • Small-scale distributed wind and PV power is suitable for microgrid integration. • Medium-sized wind and PV power consumed through the main grid is reasonable. • Large-scale wind and PV can be combined and transmitted with hydro or thermal power. [ABSTRACT FROM AUTHOR]