An Assessment Of Wind Characteristics,Performance Characterization And Availability Of Site Specific Wind

Renewable energy is expanding throughout the world rapidly.However,the wind energy technology has been facing some serious issues,especially the immature failure of mechanical and electrical components.The immature failures have effects on wind energy technology,for example,increasing the cost of repair and replacement,minimizing the availability and performance that could be the cause of increasing cost of energy.Therefore,the performance and availability are key issues that need to be addressed.The wind characteristics assessment is essential for near reality assessment of increasing performance and availability of wind farms.In this thesis,three specific sites are selected which representing the wind class 3 and 7.The main contents and results of this thesis are enumerated as:(1)The wind characteristics,including wind speed,direction and other meteorological data of Nooriabad,Pakistan is studied for a period of a year.The wind energy density,annual energy output and capacity factors have been calculated at two referenced heights 30 and 50 m.The empirical,maximum likelihood,modified maximum likelihood,energy pattern and graphical methods were used to determine the Weibull and other dependent parameters.The correlation coefficient and root mean square error values were used to assess the accuracies of methods.The results show that graphical method does not fit well except all other methods fit well with the measured wind speed.The observed frequency distribution showed that Weibull distribution gave better fitting than Rayleigh distribution.The results show that the Nooriabad site has potential to install utility wind turbines to generate energy at the lowest cost per kWh at 50 m height.(2)The wind climate parameters,performance functions and reliability assessment model have been developed.The developed model encompasses local wind characteristics assessment including wind shear and diurnal wind variations.The performance assessment is based on technical and real availability,capacity factor and failure rate of mechanical and electrical components.The Weibull method is used to determine the reliability.The novel maintenance model was developed for improving the reliability and performance of wind farm.Also energy volume and financial constraints model were developed.(3)The onsite wind farm performance assessment model and performance based cost model have been developed.The average values of wind characteristics using entire data set,showed the strong presence at the hub height of wind turbine.The power coefficient is dropped when wind speed crosses the rated speed.So,the efficiency of wind turbine is decreased at an increased wind speed.Tip speed ratio shows that a wind turbine operating close to optimal lift and drag that will exhibit the performance level.The assessment showed that the wind turbine performs better at below the rated speed.The estimated average levelized cost of energy makes it competitive to other energy technologies.(4)The site specific wind assessment is necessary to ascertain the influence of natural variation of wind climate parameters on wind turbine and energy production.The objective is to study the natural variation of wind parameters and their effects on energy generation and on wind turbine components.The weight model has been developed to determine the effects on wind turbine components,energy generation and on pre and post effects of model on energy cost.The result shows that site specific wind force gave rise on wind turbine which ultimately became cause of drop in energy.The lift coefficient,drag coefficient and pitching moment considering values showed an increase in force that results drop in energy.The cost assessment shows that the cost of energy generation was increased.The results show that the Hawkes bay in Pakistan has potential to generate the energy at the lowest cost/kWh but needs design adjustment in wind turbines accordingly.The studied sites fall under the wind class 3 and 7 showed the strong presence of wind characteristics.The precise determination of wind characteristics for each wind class is essential for installation of wind farms.The site specific wind characteristics and their correlation showed that wind environment has significant influence on performance and availability of wind farms.The results of site specific assessment pave the way for site specific design optimization of wind turbines.