Investigation on wind power potential on Hong Kong islands—an analysis of wind power and wind turbine characteristics

This paper discusses the potential for electricity generation on Hong Kong islands through an analysis of the local weather data and typical wind turbine characteristics. An optimum wind speed, u_op, is proposed to choose an optimal type of wind turbine for different weather conditions. A simulation model has been established to describe the characteristics of a particular wind turbine. A case study investigation allows wind speed and wind power density to be obtained using different hub heights, and the annual power generated by the wind turbine to be simulated. The wind turbine's capacity factor, being the ratio of actual annual power generation to the rated annual power generation, is shown to be 0.353, with the capacity factor in October as high as 0.50. The simulation shows the potential for wind power generation on the islands surrounding Hong Kong.     

Sensitivity of southern California wind energy to turbine characteristics

Using output from a high‐resolution meteorological simulation, we evaluate the sensitivity of southern California wind energy generation to variations in key characteristics of current wind turbines. These characteristics include hub height, rotor diameter and rated power, and depend on turbine make and model. They shape the turbine's power curve and thus have large implications for the energy generation capacity of wind farms. For each characteristic, we find complex and substantial geographical variations in the sensitivity of energy generation. However, the sensitivity associated with each characteristic can be predicted by a single corresponding climate statistic, greatly simplifying understanding of the relationship between climate and turbine optimization for energy production. In the case of the sensitivity to rotor diameter, the change in energy output per unit change in rotor diameter at any location is directly proportional to the weighted average wind speed between the cut‐in speed and the rated speed. The sensitivity to rated power variations is likewise captured by the percent of the wind speed distribution between the turbines rated and cut‐out speeds. Finally, the sensitivity to hub height is proportional to lower atmospheric wind shear. Using a wind turbine component cost model, we also evaluate energy output increase per dollar investment in each turbine characteristic. We find that rotor diameter increases typically provide a much larger wind energy boost per dollar invested, although there are some zones where investment in the other two characteristics is competitive. Our study underscores the need for joint analysis of regional climate, turbine engineering and economic modeling to optimize wind energy production. Copyright © 2012 John Wiley & Sons, Ltd.     

A new semi-empirical wind turbine capacity factor for maximizing annual electricity and hydrogen production

The capacity factor is an important wind turbine parameter which is ratio of average output electrical power to rated electrical power of the wind turbine. Another main factor, the AEP, the annual energy production, can be determined using wind characteristics and wind turbine performance. Lower rated power may lead to higher capacity factor but will reduce the AEP. Therefore, it is important to consider simultaneously both the capacity factor and the AEP in design or selecting a wind turbine. In this work, a new semi-empirical secondary capacity factor is introduced for determining a rated wind speed at which yearly energy and hydrogen production obtain a maximum value. This capacity factor is expressed as ratio of the AEP for wind turbine to yearly wind energy delivered by mean wind speed at the rotor swept area. The methodology is demonstrated using the empirical efficiency curve of Vestas-80 2 MW turbine and the Weibull probability density function. Simultaneous use of the primary and the secondary capacity factors are discussed for maximizing electrical energy and hence hydrogen production for different wind classes and economic feasibility are scrutinized in several wind stations in Kuwait.     

Potential wind power generation in South Egypt

Egypt is one of the developing countries. The production of electricity in Egypt is basically on petroleum, natural gas, hydro-power and wind energy. The objective of this work to prove the availability of sufficient wind potential in the wide area of deep south Egypt for the operation of wind turbines there. Nevertheless, it gives in general an approximate profile which is useful to the wind parks design for this area. The data used in the calculation are published and analyzed for the first time. The diagrams of the measured wind data for three meteorological stations over a period of two years (wind speed, frequency, direction), wind shear coefficient, the mean monthly and annual wind speed profile for every location are presented. Monthly Weibull parameters, standard deviation and coefficient of variation have been statistically discussed. A comparison of the rose diagrams shows that the wind speed is more persistent and blow over this region of Egypt in two main sectors N and NNW with long duration of frequencies from 67% to 87% over the year with an average wind speed in the range 6.8-7.9 m/s at the three stations. Evaluation of monthly wind energy density at 10 m height by two different methods was carried out. And the final diagram for every site shows no significant difference between them. The annual natural wind energies at 70 m A.G.L. lie between 333 and 377 W/m² for Dakhla South and Kharga stations, respectively, which is similar to the inland wind potential of Vindeby (Denmark) and some European countries. These results indicate that Kharga and Dakhla South locations are new explored sites for future wind power generation projects.     

Some statistical characteristics of monthly average wind speed at various heights

The article, which is a segment of a complex wind energy examination, uses statistical methods to analyze the time series of monthly average wind speed in the period between 1991 and 2000 measured on seven Hungarian meteorological stations. Empirical distribution of measured monthly average wind speeds is approximated by theoretical distributions to claim that certain distributions are universal, i.e. independent of orography. We used one of them, the Weibull distribution, to generate the distribution of monthly average wind speeds on levels different from anemometer altitude as well, then we calculate the averages for the entire period and we fit a power function on them. Thus we can demonstrate a correlation between Hellmann's wind profile law and the Weibull distribution.     

Evaluation of wind energy potential and electricity generation on the coast of Mediterranean Sea in Egypt

Wind data from 10 coastal meteorological stations along the Mediterranean Sea in Egypt have been used for statistical analysis to determine the wind characteristics. It was found that three stations show annual mean wind speed greater than 5.0 m/s. In order to identify the Weibull parameters for all stations two different methods were applied.The methodical analysis for all stations was done for the corrected monthly and annual mean wind power at a height of 10 m, over roughness class 0 (water). The recommended correlation equation was also stated for Mediterranean Sea zone in Egypt. Also the wind power densities for heights of 30–50 m were calculated for all stations. Three of them are the best locations, namely: Sidi Barrani, Mersa Matruh, and El Dabaa, where these contiguous stations have great abundantly wind energy density.A technical assessment has been made of the electricity generation using WASP program for two commercial turbines (300 kW and 1 MW) considering at the three promising sites. The wind turbine of capacity 1 MW was found to produce an energy output per year of 2718 MW h at El Dabaa station, and the production costs was found 2€ cent/kW h.     

Spatial and temporal characteristics of wind and wind power off the coasts of Brittany

The main objective of this paper is to thoroughly examine the remotely sensed wind characteristics around the coasts of Brittany as well as some more specific areas. The offshore wind power potential is then assessed. To achieve this objective, information on wind speed and direction with sufficient spatial and temporal sampling under all weather conditions and during day and night is required. This study uses more than 12 years (December 1999–December 2012) of consistent remotely sensed data retrieved from the ASCAT and QuikSCAT scatterometers to estimate the conventional moments and associated wind distribution parameters. The latter are comparable to wind observations from meteorological stations. Furthermore, combining in-situ and scatterometer wind information enables an improved assessment of the spatial and temporal wind structures at specific locations of interest to be made. The wind statistical results are used to study the spatial and temporal patterns of the wind power. Although the main parameters characterizing wind power potential such as mean, variability, maximum energy, wind speed and intra-annual exhibit seasonal features, significant inter-annual variability is also depicted. Furthermore, differences are found between the wind power estimated for northern and for southern Brittany.     

A statistical investigation of wind characteristics and wind energy potential based on the Weibull and Rayleigh models in Rwanda

A wind energy system converts the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical uses and transform the economy of rural areas where access to water and electricity is very restricted and industry is almost nonexistent in most of the developing countries like Rwanda. Assessing wind power potential for a location is an imperative requirement before making a decision for the installation of windmills or a wind electric generator and evaluating plans for relating projects. The aim of the present study was to evaluate the potential of wind resource in Rwanda and to constitute a database for the users of the wind power. A time series of hourly daily measured wind speed and wind direction for the period between 1974 and 1993 on five main Rwandan meteorological stations was provided by the National Meteorology Department. Statistical methods applying Weibull and Rayleigh distribution were presented to evaluate the wind speed characteristics and the wind power potential at a height of 10 m above ground level using hourly monthly average data. Those characteristics were extrapolated for higher levels in altitude. The results give a global picture of the distribution of the wind potential in different locations of Rwanda.     

Performance evaluation of pairing between sites and wind turbines

This paper presents a simple method for determination of pairing between sites and wind generators. It requires six parameters to describe the matching between turbine models and site characteristics, and the energy output performance can thus be easily estimated and used as the index of pairing effectiveness. To describe a Weibull model of wind speed distribution, the shape parameter and the scale parameter are necessarily required. Besides, four other parameters are chosen to specify the characteristics of the power curve of a wind generator: the cut-in speed, the rated speed, the cut-off speed and the nominal power. By combining these six parameters, the average power output of some particular wind turbine at a specific site can be practically and quickly approximated as a reference for turbine siting consideration. An example is also shown to demonstrate the utilization of the proposed method to choose between a group of wind sites and a list of commercial wind turbines.     

Electricity generation and wind potential assessment at Hurghada, Egypt

A technical and economic assessment has been made of the generation of electricity using wind turbines at one of the most promising wind sites in Egypt: Hurghada. In this paper, we used wind data recorded over 23 years for this site. The WASP program was used to calculate the values of wind speed frequency for the station, their seasonally values have been estimated and compared with measured data.Weibull parameters and the power law coefficient (n) for all seasons at different heights (10–70 m) has been estimated and used to describe the distribution and behavior of seasonal wind speed and their frequencies at Hurghada. The monthly and annual values of wind potential at a height of 70 m were obtained by extrapolation of the 10 m data from the results of our previous article [Ahmed Shata AS, Hanitsch R. The potential of electricity generation on the east coast of Red Sea in Egypt. Renew Energy 2006;31:1597–615] using the power law.Also, the monthly plant load factor (PLF) has been estimated, which is used to determine the expected annual energy output of a wind energy conversion system (WECS).Variation of annual capacity factor with rated wind speed for 10 different wind turbines has been studied. The lower the rated speed for the WECS of the same height, the higher will be the capacity factor values. The expected electrical energy cost of kWh produced by the wind turbine (Repower MM82) with a capacity of 2 MW considered for Hurghada station was found to be less than 1.5 € cent/kWh.     

A survey on the assessment of wind energy potential in Egypt

In this paper, wind data obtained from the Egyptian Meteorological Authority are used to assess monthly and annual wind power and wind energy. The study is based on data from 15 anemometer meteorological stations, distributed all over Egypt and covering a period ranging from 1973 to 1994. For these stations the wind data are summarized. The wind energy potential at the 25 m height was obtained by extrapolation of data at 10 m using a power-law expression. The result presents the mean wind energy density estimates and potential for application in Egypt. The analysis showed that along Red Sea coasts, the annual wind energy flux is found to be high, which indicates that these coastal stations are possible locations for wind energy utilization. On both the Mediterranean coast and in the interior parts of Egypt, some stations are of low available wind energy, while others are found to be rather high. Also, the two Weibull distribution parameters have been estimated from the wind speed data for some meteorological stations and the wind power density is calculated using the values of these parameters.     

Designing an index for assessing wind energy potential

To meet the increasing global demand for renewable energy, such as wind energy, an increasing number of wind parks are being constructed worldwide. Finding a suitable location requires a detailed and often costly analysis of local wind conditions. Plain average wind speed maps cannot provide a precise forecast of wind power because of the non-linear relationship between wind speed and production. We suggest a new approach to assess the local wind energy potential. First, meteorological reanalysis data are applied to obtain long-term low-scale wind speed data at specific turbine locations and hub heights. Second, the relation between wind data and energy production is determined via a five parameter logistic function using actual high-frequency energy production data. The resulting wind energy index allows for a turbine-specific estimation of the expected wind power at an unobserved location. A map of the wind power potential for Germany exemplifies our approach.     

Monthly and seasonal assessment of wind energy characteristics at four monitored locations in Liguria region (Italy)

The aim of this paper is to investigate the monthly and seasonal variation of the wind characteristics in term of wind energy potential using the wind speed data collected between 2002 and 2008 for four meteorological stations in Liguria region, in Northwest of Italy, namely Capo Vado, Casoni, Fontana Fresca and Monte Settepani. The results show that Capo Vado is the best site with a monthly mean wind speed between 2.80 and 9.98 m/s at a height of 10 m and a monthly wind power density between 90.71 and 1177.97 W/m², while the highest energy produced may be reached in December with a value of 3800 MWh. This study may provide information for developing wind energy sites and planning economical wind turbines capacity for the electricity production in Liguria region, as well as an example of how, deepening the analysis at monthly and seasonal scale, the characteristics of the sites might fall in quite different classes of power density.     

Feasibility study of harnessing wind energy for turbine installation in province of Yazd in Iran

This paper analyses the wind speed of some major cities in province of Yazd which is located in central part of Iran. Also, the feasibility study of implementing wind turbines to take advantage of wind power is reviewed and then the subject of wind speed and wind potential at different stations is considered. This paper utilized wind speed data over a period of almost 13 years between 1992 and 2005 from 11 stations, to assess the wind power potential at these sites. In this paper, the hourly measured wind speed data at 10 m, 20 m and 40 m height for Yazd province have been statically analyzed to determine the potential of wind power generation. Extrapolation of the 10 m data, using the Power Law, has been used to determine the wind data at heights of 20 m and 40 m. The results showed that most of the stations have annual average wind speed of less than 4.5 m/s which is considered as unacceptable for installation of the wind turbines. City of Herat has higher wind energy potential with annual wind speed average of 5.05 m/s and 6.86 m/s, respectively, at height of 10 m and 40 m above ground level (AGL). This site is a good candidate for remote area wind energy applications. But some more information is required, because the collected data for Herat is only for 2004. Cities of Aghda with 3.96 m/s, Gariz with 3.95 m/s, and Maybod with 3.83 m/s annual wind speed average at height of 10 m above ground level are also able to harness wind by installing small wind turbines. The Tabas and Bafgh sites wind speed data indicated that the two sites have lower annual wind speed averages between 1.56 m/s and 2.22 m/s at 10 m height. The monthly and annual wind speeds at different heights have been studied to ensure optimum selection of wind turbine installation for different stations in Yazd.     

The potential of electricity generation on the east coast of Red Sea in Egypt

Wind characteristics have been analyzed based on long-term measured data of monthly mean wind speed of seven meteorological stations along the east coast of Red Sea in Egypt. It was found that the windiest stations (Region A) namely (Zafarana, Abu Darag, Hurghada and Ras Benas) have annual mean wind speeds (7.3, 7.2, 6.4 and 5.5 m/s) at 10 m height, respectively.Numerical estimations using measured wind speeds and frequencies to calculate the two Weibull parameters were carried out and two methods were applied.The methodical analysis for the corrected monthly wind power density at a height of 10 m above ground level, over roughness class 0 (water), for each station was done. The recommended correlation equation was also stated for Red Sea zone in Egypt. Also the corrected annual wind power density at the heights (50–70) m was obtained for all stations. Moreover, calculations show that the four stations in (Region A) have a huge energy potential available (430–1000 W/m²) at 70 m height, while Quseir and Suez stations (Region B) have good wind power density (170–190 W/m²) at 50 m height.A technical and economic assessment has been made of electricity generation from two turbines machines having capacity of (1000 and 600 kW) considered in Regions A & B, respectively, using WASP program. The yearly energy output, capacity factor and the electrical energy cost of kWh produced by the two different turbines in each region were estimated. The production costs of four stations in Region A was found to be less than 2€ cent/kWh and compared with retail tariff.     

A study of the wind speed and wind energy availability in Bangladesh

Characteristics of wind speed data for three recent years, recorded at 14 stations of the Bangladesh Meteorological Department, have been studied. The data have been used to compute the monthly average wind speed and the wind energy availability for the stations. Average values of monthly wind speed for 1931–1960 have been employed to obtain the energy availability from the energy pattern factor, and the two sets of results have been compared. It has been found that, for the Chittagong station, the frequency distributions have good fits of the Weibull type.     

Evaluation of wind energy potential and electricity generation at six locations in Turkey

In this study, wind characteristics were analyzed using the wind speed data collected of the six meteorological stations in Turkey during the period 2000–2006. The annual mean wind speed of the six stations (Erzurum, Elaz??, Bingöl, Kars, Manisa and Ni?de) is obtained as 8.7, 8.5, 5.9, 6.9, 7.4 and 8.0 m/s at 10 m height, respectively. The mean annual value of Weibull shape parameter k is between 1.71 and 1.96 while the annual value of scale parameter c is between 6.81 and 9.71 m/s. A technical assessment has been made of electricity generation from four wind turbines having capacity of (600 kW, 1000 kW, 1500 kW and 2000 kW). The yearly energy output and capacity factor for the four different turbines were calculated.     

On wind speed pattern and energy potential in Nigeria

The aim of this paper is to review wind speed distribution and wind energy availability in Nigeria and discuss the potential of using this resource for generation of wind power in the country. The power output from a wind turbine is strongly dependent on the wind speed and accurate information about the wind data in a targeted location is essential. The annual mean wind speeds in Nigeria range from about 2 to 9.5 m/s and the annual power density range between 3.40 and 520 kW/m² based on recent reported data. The trend shows that wind speeds are low in the south and gradually increases to relatively high speeds in the north. The areas that are suitable for exploitation of wind energy for electricity generation as well as for water pumping were identified. Also some of the challenges facing the development of wind energy and suggested solutions were presented.     

The application of artificial neural networks to mapping of wind speed profile for energy application in Nigeria

Modelling and prediction of wind speed are essential prerequisites in the sitting and sizing of wind power applications. The profile of wind speed in Nigeria is modelled using artificial neural network (ANN). The ANN model consists of 3-layered, feed-forward, back-propagation network with different configurations, designed using the Neural Toolbox for MATLAB. The monthly mean daily wind speed data monitored at 10 m above ground level for a period of 20 years (1983–2003) for 28 ground stations operated by the Nigeria Meteorological Services (NIMET) were used as training (18 stations) and testing (10 stations) dataset. The geographical parameters (latitude, longitude and altitude) and the month of the year were used as input data, while the monthly mean wind speed was used as the output of the network. The optimum network architecture with minimum Mean Absolute Percentage Error (MAPE) of 8.9% and correlation coefficient (r) between the predicted and the measured wind speed values of 0.9380 was obtained. The predicted monthly wind speed ranged from 0.9–13.1 m/s with an annual mean of 4.7 m/s. The model predicted wind speed values are given in the form of monthly maps, which can be easily used for assessment of wind energy potential for different locations within Nigeria.     

Analysis of wind potential and characteristics in North Aegean, Greece

Wind data for the years 2000 and 2001 were analyzed to evaluate the wind potential of the Mikra–Thessaloniki, region in northern Greece. The objective of the analysis was the establishment of the required criteria to answer the question: “are the renewable energy sources capable to maintain the operation of a desalination pilot unit?” The polar diagrams of the wind (wind speed, frequency, direction), the mean monthly and annual wind speed profile and the Weibull distributions for the years 2000 and 2001 are presented.