feasibility assessment for use of wind energy in ardebil and zanjan provinces

introductionin comparison with fossil fuels which pollute the lower layer of the atmosphere, use of windenergy has many environmental and economic advantages. wind is a clean and renewableenergy resource and use of the energy in the recent decades has been welcomed so much in theworld. energy plays an important role in the development of each society. all differentactivities including housing, transport, industry and agriculture may be dependent on this sourceof energy. the use of clean and renewable energy such as wind has environmental advantagescompared with fossil fuels. the increase of population and demand for energy has caused thatwind energy potential is considered as an alternative source of energy. wind speed is the mostimportant parameter of the wind energy. this is used in the analyses relating to this energybecause wind power has a cubic relation with wind speed.methodologythe parameters of weibull distribution is used to estimate the parameters related to wind energyand determine the sites which have wind energy potential. thus, it is important to use propermethods in the estimation. in this paper, 6 distinct methods for estimating parameters of weibulldistribution have been considered. for this purpose, 5 synoptic station which have adequate 3hours wind speed data from 1987 to 2009 (23 years) have been selected. these stations are:ardebil, parsabad, khalkhal, zanjan and khoramadare. the method of moments, empirical,graphical, energy pattern factor and maximum likelihood methods and probably weightedmoments have been employed to estimate scale (m/s) and shape parameters (dimensionless) ofweibull distribution. for determining the best parameters estimating method using cumulativedistribution function of the weibull distribution (f(v)), expected values have been generated.the chi square test has been used to select the appropriate method. cumulative distributionfunction has also been used in order to calculate the probability that wind speed is smaller thanor equal to 5 m/s. in addition to 10 m height, weibull distribution parameters and parametersrelated to wind energy potential namely, wind power density (wm-2), wind energy density(kwh-1m-2), the most probable wind speed (ms-1) and the maximum energy carrying wind speed(ms-1) have been computed in 20 and 40 m.results and discussionamong considered methods, method of moment because of having higher significance level andlower chi square compared with other methods has been selected as the best one to estimateweibull distribution parameters. using this method, scale and shape parameters of weibulldistribution at 20 and 40 m height has also been estimated. then, wind energy characteristics,namely, wind power density (wm-2), wind energy density (kwh-1m-2), the most probable windspeed (ms-1) and the maximum energy carrying wind speed (ms-1) have been computed. theresults have showed that at monthly time scale and in 10 m height, the maximum value of k wasobserved in zanjan and khalkhal stations on june and the lowest value of k in khalkhal stationin january. the maximum value of c was observed at ardebil in februrary and the lowest valueof c at parsabad in november. using the wind power density all the stations are ordered asfollowing: ardebil, khoramdareh, khalkhal, parsabad and zanjan. this order shows thatardebil has high potential of wind energy and zanjan has the minimum potential.conclusionwe can summarize main conclusions drawn from this investigation as following:• in this study, among the considered methods, the method of moment is specified as theproper one and using parameters obtained from this method, features relating to windenergy in studied stations were estimated.• among the studied stations, the maximum of wind power density is observed atardebil. in this station, in 40 meter height the largest value of wind power densitywhich was equal to 491w/m2 is also observed. the minimum value of wind powerdensity is observed in zanjan which is equal to 107.2 w/m2.• the probability that wind speed is smaller than or equal to 5 m/s was calculated usingphysical geography research quarterly, 46 (3), fall 2014 3cumulative distribution function for the studied stations in 3 heights namely 10, 20 and40 meter. the results showed that in 10 m height, among studied stations the highestprobability belongs to ardebil. after ardebil station, the highest probability wasobserved in khoramdare.• in 10 meter height, at parsabad, khalkhal and zanjan in all the year the probability islower than ardebil and khoramdareh. so, in these stations the operating possibility ofwind turbines will be low.