A Statistical Analysis of Wind Speed and Power Density Based on Weibull and Rayleigh Models of Jumla, Nepal

In the present study, wind speed data of Jumla, Nepal have been statistically analyzed. For this purpose, the daily averaged wind speed data for 10 year period (2004-2014: 2012 excluded) provided by Department of Hydrology and Meteorology (DHM) was analyzed to estimate wind power density. Wind speed as high as 18 m/s was recorded at height of 10 m. Annual mean wind speed was ascertained to be decreasing from 7.35 m/s in 2004 to 5.13 m/s in 2014 as a consequence of Global Climate Change. This is a subject of concern looking at government’s plan to harness wind energy. Monthly wind speed plot shows that the fastest wind speed is generally in month of June (Monsoon Season) and slowest in December/January (Winter Season). Results presented Weibull distribution to fit measured probability distribution better than the Rayleigh distribution for whole years in High altitude region of Nepal. Average value of wind power density based on mean and root mean cube seed approaches were 131.31 W/m2/year and 184.93 W/m2/year respectively indicating that Jumla stands in class III. Weibull distribution shows a good approximation for estimation of power density with maximum error of 3.68% when root mean cube speed is taken as reference.

Analysis of offshore wind energy resources of China

With the economic development, the problems of energy shortage become increasingly severe. As offshore wind energy has advantages, namely it is clean, renewable, not accounting for land area, without noise pollution, with large reserves, etc., which gradually attracts people＇s attention. In this paper, China＇s offshore annual average wind field and monthly average wind field under the mean climate state conditions are obtained, and the corresponding wind density distribution is calculated. China＇s offshore wind energy reserves and distribution conditions through the analysis of wind energy density distribution are summarized, and finally some suggestions for coastal offshore wind energy development and utilization in China are put forward.

Analysis and Assessment of Wind Energy Potential of Socotra Archipelago in Yemen

The increasing use of fossil fuels has a significant impact on the environment and ecosystem,which increases the rate of pollution.Given the high potential of renewable energy sources inYemen and the absence of similar studies in the region,this study aims to examine the potential of wind energy in Socotra Island.This was done by analyzing and evaluating wind properties,determining available energy density,calculating wind energy extracted at different altitudes,and then computing the capacity factor for a number of wind turbines and determining the best.The average wind speed in Socotra Island was obtained from the Civil Aviation and Meteorology Authority data,only for the five-year data currently available.The results showed high wind speeds from June to September(9.85-14.88 m/s)while the wind speed decreased for the rest of the year.The average wind speed in the five years was 7.95 m/s.The average annual wind speed,wind energy density,and annual energy density were calculated at different altitudes(10,30,and 50 m).According to the International Wind Energy Rating criteria,the region of Socotra Island falls under Category 7 and is classified as‘Superb’for most of the year.This study provides useful information for developing wind energy and an efficient wind approach.

Analysis and Assessment of Wind Energy Potential of Almukalla in Yemen

Energy is an essential element for any civilized country’s social and economic development,but the use of fossil fuels and nonrenewable energy forms has many negative impacts on the environment and the ecosystem.The Republic of Yemen has very good potential to use renewable energy.Unfortunately,we find few studies on renewable wind energy in Yemen.Given the lack of a similar analysis for the coastal city,this research newly investigates wind energy’s potential near the Almukalla area by analyzing wind characteristics.Thus,evaluation,model identification,determination of available energy density,computing the capacity factors for several wind turbines and calculation of wind energy were extracted at three heights of 15,30,and 50meters.Average wind speeds were obtained only for the currently available data of five recent years,2005–2009.This study involves a preliminary assessment of Almukalla’s wind energy potential to provide a primary base and useful insights for wind engineers and experts.This research aims to provide useful assessment of the potential of wind energy in Almukalla for developing wind energy and an efficient wind approach.The Weibull distribution shows a perfect approximation for estimating the intensity of Yemen’s wind energy.Depending on both theWeibullmodel and the results of the annual wind speed data analysis for the study site in Mukalla,the capacity factor for many turbines was also calculated,and the best suitable turbine was selected.According to the International Wind Energy Rating criteria,Almukalla falls under Category 7,which is,rated“Superb”most of the year.

Analysis and Assessment of Wind Energy Potential of Al-Hodeidah in Yemen

Renewable energy is one of the essential elements of the social and economic development in any civilized country.The use of fossil fuels and the non-renewable form of energy has many adverse effects on the most of ecosystems.Given the high potential of renewable energy sources in Yemen and the absence of similar studies in the region,this study aimed to examine the wind energy potential of Hodeidah-Yemen Republic by analyzing wind characteristics and assessment,determining the available power density,and calculate the wind energy extracted at different heights.The average wind speed of Hodeidah was obtained only for the data currently available for the five years 2005–2009(due to the current economic and the political situation in Yemen).The results show that the average wind speed in the five years is(25.2 W/m2 at 10 m,93.9 W/m2 at 30 m,and 173.5 W/m2 at 50 m).The average yearly wind power density(25.2 W/m2 at 10 m,93.9 W/m2 at 30 m and 173.5 W/m2 at 50m),and the average yearly energy density(220.8 KWh/m2/year at 10 m,822.6 KWh/m2/year at 30 m and 1519.9 KWh/m2/year at 50 m).This research is a preliminary assessment of the potential of wind energy in Hodeidah,which provides useful information for developing wind energy and an efficient wind approach.According to the International Wind Energy Rating criteria,the region of Hodeidah falls under‘Class 2’and is classified as‘Marginal’for most of the year.

Assessment Method of Offshore Wind Resource Based on Multi-dimenssiional Indexes System

Traditional assessment indexes could not fully describe offshore wind resources,for the meteorological properties of offshore are more complex than onshore.As a result,the uncertainty of offshore wind power projects would be increased and final economic benefits would be affected.Therefore,a study on offshore wind resource assessment is carried out,including three processes of“studying data sources,conducting multidimensional indexes system and proposing an offshore wind resource assessment method based on analytic hierarchy process(AHP).First,measured wind data and two kinds of reanalysis data are used to analyze the characteristics and reliability of data sources.Second,indexes such as effective wind speed occurrence,affluent level occurrence,coefficient of variation,neutral state occurrence have been proposed to depict availability,richness,and stability of offshore wind resources,respectively.Combined with existing parameters(wind power density,dominant wind direction occurrence,water depth,distance to coast),a multidimensional indexes system has been built and on this basis,an offshore wind energy potential assessment method has been proposed.Furthermore,the proposed method is verified by the annual energy production of five offshore wind turbines and practical operating data of four offshore wind farms in China.This study also compares the ranking results of the AHP model to two multi-criteria decision making(MCDM)models including weighted aggregated sum product assessment(WASPAS)and multi-attribute ideal real comparative analysis(MAIRCA).Results show the proposed method gains well in practical engineering applications,where the economic score values have been considered based on the offshore reasonable utilization hours of the whole life cycle in China.

Projected near-surface wind speed and wind energy over Central Asia using dynamical downscaling with bias-corrected global climate models

Wind energy development in Central Asia can help alleviate drought and fragile ecosystems.Nevertheless,current studies mainly used the global climate models(GCMs)to project wind speed and energy.The simulated biases in GCMs remain prominent,which induce a large uncertainty in the projected results.To reduce the uncertainties of projected near-surface wind speed(NSW)and better serve the wind energy development in Central Asia,the Weather Research and Forecasting(WRF)model with bias-corrected GCMs was employed.Compared with the outputs of GCMs,dynamical downscaling acquired using the WRF model can better capture the high-and low-value centres of NSWS,especially those of Central Asia's mountains.Meanwhile,the simulated NSWS bias was also reduced.For future changes in wind speed and wind energy,under the Representative Concentration Pathway 4.5(RCP4.5)scenario,NSWS during 2031-2050 is projected to decrease compared with that in 19862005.The magnitude of NSwS reduction during 2031-2050 willreach 0.1 m s^(-1).and the maximum reduction is projected to occur over the central and western regions(>0.2 m s^(-1)).Furthermore,future wind power density(WPD)can reveal nonstationarity and strong volatility,although a downward trend is expected during 2031-2050.In addition,the higher frequency of wind speeds at the turbine hub height exceeding 3.0 m s^(-1)can render the plain regions more suitable for wind energy development than the mountains from 2031 to 2050.This study can serve as a guide in gaining insights into future changes in wind energy across Central Asia and provide a scientific basis for decision makers in the formulation of policies for addressing climate change.

Evaluation of the wind energy potential of two south west sites in Nigeria

Wind resource assessment is a crucial first step in gauging the potential of a site to produce energy from wind turbines. In this paper, the wind energy potential of Abeokuta （07°03＇N, 03°19＇E） and Ijebu-Ode （06°47＇N, 03°58＇E）, two south west sites in Nigeria were examined. Twenty years （1990-2010） of monthly mean wind data from a 10m height were subjected to two-parameter Weibull analysis and other statistical analyses. The results show that the average annual mean wind speed variation for Abeokuta ranges from 2.2 to 5.0 m/s. For Ijebu-Ode, it ranges from 2.0 to 5.0m/s. The wind power density variation based on the Weibull analysis ranges from 4.26 to 24.51 W/m2 for Abeokuta and from 8.54 to 76.46 W/m2 for Ijebu-Ode. Ijebu-Ode was found to be the better of the two sites in terms of annual variation of mean wind speed.