The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Shafiqur Rehman - One of the best experts on this subject based on the ideXlab platform.
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Wind Shear coefficients and energy yield for dhahran saudi arabia
Renewable Energy, 2007Co-Authors: Shafiqur Rehman, Naif Mohammed AlabbadiAbstract:This study presents calculated values of Wind Shear coefficients (WSE) using measured values of Wind speed at 20, 30, and 40m above ground level (AGL), for Dhahran, Saudi Arabia. The study also includes the air density estimated using measured air temperature and surface pressure and effect of Wind Shear coefficient on energy yield from a Wind farm of 60MW installed capacity developed using 40 Wind turbines of 1500kW size. The data used in the determination of Wind Shear coefficient covered a period of almost 5 years between 4 October 1995 and 30 November 2000.
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Wind Shear coefficients and energy yield for Dhahran, Saudi Arabia
Renewable Energy, 2007Co-Authors: Shafiqur Rehman, Naif M. Al-abbadiAbstract:Abstract This study presents calculated values of Wind Shear coefficients (WSE) using measured values of Wind speed at 20, 30, and 40 m above ground level (AGL), for Dhahran, Saudi Arabia. The study also includes the air density estimated using measured air temperature and surface pressure and effect of Wind Shear coefficient on energy yield from a Wind farm of 60 MW installed capacity developed using 40 Wind turbines of 1500 kW size. The data used in the determination of Wind Shear coefficient covered a period of almost 5 years between 4 October 1995 and 30 November 2000. The study suggests a value of 0.189 of Wind Shear coefficient for the calculation of Wind speed at different heights if measured values are known at one height. No regular seasonal trend was observed in the values of Wind Shear coefficients. In case of diurnal variation, higher values were observed during nighttime and early hours of the day and comparatively smaller values during day light hours. The air density, calculated using measured temperature and pressure was found to be 1.18 kg/m 3 . The energy yield obtained using RetScreen software, showed that the actual Wind Shear coefficient presented in this paper produced around 11–12% more energy compared to that obtained using 1/7 power law. Accordingly, 2–3% higher plant capacity factors were achieved using actual site-dependent Wind Shear coefficient instead of 1/7th Wind power law exponent for the calculation of Wind speed at hub-height.
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Wind Shear coefficients and their effect on energy production
Energy Conversion and Management, 2005Co-Authors: Shafiqur Rehman, Naif M. Al-abbadiAbstract:Abstract This paper provides realistic values of Wind Shear coefficients calculated using measured values of Wind speed at 20, 30 and 40 m above the ground for the first time in Saudi Arabia in particular and, to the best of the authors’ knowledge, in the Gulf region in general. The paper also presents air density values calculated using the measured air temperature and surface pressure and the effects of Wind Shear factor on energy production from Wind machines of different sizes. The measured data used in the study covered a period of almost three years between June 17, 1995 and December 1998. An overall mean value of Wind Shear coefficient of 0.194 can be used with confidence to calculate the Wind speed at different heights if measured values are known at one height. The study showed that the Wind Shear coefficient is significantly influenced by seasonal and diurnal changes. Hence, for precise estimations of Wind speed at a height, both monthly or seasonal and hourly or night time and day time average values of Wind Shear coefficient must be used. It is suggested that the Wind Shear coefficients must be calculated either (i) using long term average values of Wind speed at different heights or (ii) using those half hourly mean values of Wind speed for which the Wind Shear coefficient lies in the range ⩾0 and ⩽0.51. The air density, calculated using measured temperature and pressure was found to be 1.18 kg/m3. The air density values were also found to vary with the season of the year and hour of the day, and hence, care must be taken when precise calculations are to be made. The air density values, as shown in this paper, have no significant variation with height. The energy production analysis showed that the actual Wind Shear coefficient presented in this paper produced 6% more energy compared to that obtained using the 1/7 power law. Similarly, higher plant capacity factors were obtained with the Wind Shear factor of 0.194 compared to that with 0.143.
Naif M. Al-abbadi - One of the best experts on this subject based on the ideXlab platform.
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Wind Shear coefficients and energy yield for Dhahran, Saudi Arabia
Renewable Energy, 2007Co-Authors: Shafiqur Rehman, Naif M. Al-abbadiAbstract:Abstract This study presents calculated values of Wind Shear coefficients (WSE) using measured values of Wind speed at 20, 30, and 40 m above ground level (AGL), for Dhahran, Saudi Arabia. The study also includes the air density estimated using measured air temperature and surface pressure and effect of Wind Shear coefficient on energy yield from a Wind farm of 60 MW installed capacity developed using 40 Wind turbines of 1500 kW size. The data used in the determination of Wind Shear coefficient covered a period of almost 5 years between 4 October 1995 and 30 November 2000. The study suggests a value of 0.189 of Wind Shear coefficient for the calculation of Wind speed at different heights if measured values are known at one height. No regular seasonal trend was observed in the values of Wind Shear coefficients. In case of diurnal variation, higher values were observed during nighttime and early hours of the day and comparatively smaller values during day light hours. The air density, calculated using measured temperature and pressure was found to be 1.18 kg/m 3 . The energy yield obtained using RetScreen software, showed that the actual Wind Shear coefficient presented in this paper produced around 11–12% more energy compared to that obtained using 1/7 power law. Accordingly, 2–3% higher plant capacity factors were achieved using actual site-dependent Wind Shear coefficient instead of 1/7th Wind power law exponent for the calculation of Wind speed at hub-height.
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Wind Shear coefficients and their effect on energy production
Energy Conversion and Management, 2005Co-Authors: Shafiqur Rehman, Naif M. Al-abbadiAbstract:Abstract This paper provides realistic values of Wind Shear coefficients calculated using measured values of Wind speed at 20, 30 and 40 m above the ground for the first time in Saudi Arabia in particular and, to the best of the authors’ knowledge, in the Gulf region in general. The paper also presents air density values calculated using the measured air temperature and surface pressure and the effects of Wind Shear factor on energy production from Wind machines of different sizes. The measured data used in the study covered a period of almost three years between June 17, 1995 and December 1998. An overall mean value of Wind Shear coefficient of 0.194 can be used with confidence to calculate the Wind speed at different heights if measured values are known at one height. The study showed that the Wind Shear coefficient is significantly influenced by seasonal and diurnal changes. Hence, for precise estimations of Wind speed at a height, both monthly or seasonal and hourly or night time and day time average values of Wind Shear coefficient must be used. It is suggested that the Wind Shear coefficients must be calculated either (i) using long term average values of Wind speed at different heights or (ii) using those half hourly mean values of Wind speed for which the Wind Shear coefficient lies in the range ⩾0 and ⩽0.51. The air density, calculated using measured temperature and pressure was found to be 1.18 kg/m3. The air density values were also found to vary with the season of the year and hour of the day, and hence, care must be taken when precise calculations are to be made. The air density values, as shown in this paper, have no significant variation with height. The energy production analysis showed that the actual Wind Shear coefficient presented in this paper produced 6% more energy compared to that obtained using the 1/7 power law. Similarly, higher plant capacity factors were obtained with the Wind Shear factor of 0.194 compared to that with 0.143.
Naif Mohammed Alabbadi - One of the best experts on this subject based on the ideXlab platform.
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Wind Shear coefficients and energy yield for dhahran saudi arabia
Renewable Energy, 2007Co-Authors: Shafiqur Rehman, Naif Mohammed AlabbadiAbstract:This study presents calculated values of Wind Shear coefficients (WSE) using measured values of Wind speed at 20, 30, and 40m above ground level (AGL), for Dhahran, Saudi Arabia. The study also includes the air density estimated using measured air temperature and surface pressure and effect of Wind Shear coefficient on energy yield from a Wind farm of 60MW installed capacity developed using 40 Wind turbines of 1500kW size. The data used in the determination of Wind Shear coefficient covered a period of almost 5 years between 4 October 1995 and 30 November 2000.
Jompob Waewsak - One of the best experts on this subject based on the ideXlab platform.
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Wind Shear Coefficients and their Effect on Energy Production
Energy Procedia, 2017Co-Authors: Warit Werapun, Yutthana Tirawanichakul, Jompob WaewsakAbstract:Abstract Generally Wind Shear coefficient is used to estimate the Wind speed at higher elevations, while the local meteorological anemometers monitor one elevation. The well-known equation for estimating Wind Shear coefficients is a power law. This paper assesses Wind Shear and its effects on annual energy production from Wind speed data on Phangan island, collected from December 2011 to November 2012 at locations 65 and 120 m above ground level (agl). The annual, monthly, and diurnal variations of Wind Shear coefficient were investigated. The annual energy production was assessed by using the Wind turbine power curve. The results show that the difference between Wind energy production from extrapolated Wind data and the measured energy production may be up to 35%.
Xuefei Wang - One of the best experts on this subject based on the ideXlab platform.
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use of spatio temporal calibrated Wind Shear model to improve accuracy of Wind resource assessment
Applied Energy, 2018Co-Authors: Xuefei WangAbstract:Abstract Wind Shear models are commonly used to predict the Wind speed at Wind turbine hub heights from the Wind data collected at the elevation of the monitoring station. In many cases, the model parameters are based on empirical values recommended by design specifications that reflect the site conditions. This paper evaluates the benefits of incorporating site-specific Wind data to calibrate the Wind Shear model parameters. Wind speed data collected by a ZephIR® Light Detection and Ranging (LiDAR) system over a 2-year (Oct. 2010–Sept. 2012) period are used for the analyses. The atmospheric stability is found to have appreciable effects on the Wind Shear parameters, i.e. Wind Shear coefficients (WSC) for the power law model and roughness lengths for the logarithmic law Wind Shear models. The calibrated Wind Shear model parameters by the monitored Wind data during the first year are presented in the format of a contour map to demonstrate the spatio-temporal variations, which shows daily and seasonal variations. The calibrated Wind Shear models are then validated by the Wind data collected during the second year, which demonstrates decent performance. The accuracy and performance of incorporating site-specific Wind Shear model calibration to predict the Wind energy resource is evaluated, where six different methods are compared. The results show that the consideration of spatio-temporal variations of Wind Shear model parameters achieved improve performance over the application of the empirical or yearly-averaged Wind Shear model parameters in extrapolating the Wind speed. It is also found that the performance of considering spatio-temporal Wind Shear parameters are even better at higher elevations. Furthermore, the analyses find that the use of empirical Wind Shear model parameters underestimates the Wind energy output at the studied sites. Site-specific calibration of the Wind Shear models could further improve the accuracy of Wind energy assessment by considering the site condition and the variability in the atmospheric stability.
