Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

How wind speed shear and directional veer affect the power production of a megawatt-scale operational wind turbine

Journal Article · · Wind Energy Science (Online)
 [1];  [2];  [3]
  1. Univ. of Washington, Seattle, WA (United States); Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
+ Show Author Affiliations
Most megawatt-scale wind turbines align themselves into the wind as defined by the wind speed at or near the center of the rotor (hub height). However, both wind speed and wind direction can change with height across the area swept by the turbine blades. A turbine aligned to hub-height winds might experience suboptimal or superoptimal power production, depending on the changes in the vertical profile of wind, also known as shear. Using observed winds and power production over 6 months at a site in the high plains of North America, we quantify the sensitivity of a wind turbine's power production to wind speed shear and directional veer as well as atmospheric stability. We measure shear using metrics such as α (the log-law wind shear exponent), βbulk (a measure of bulk rotor-disk-layer veer), βtotal (a measure of total rotor-disk-layer veer), and rotor-equivalent wind speed (REWS; a measure of actual momentum encountered by the turbine by accounting for shear). We also consider the REWS with the inclusion of directional veer, REWSθ, although statistically significant differences in power production do not occur between REWS and REWSθ at our site. When REWS differs from the hub-height wind speed (as measured by either the lidar or a transfer function-corrected nacelle anemometer), the turbine power generation also differs from the mean power curve in a statistically significant way. This change in power can be more than 70 kW or up to 5 % of the rated power for a single 1.5 MW utility-scale turbine. Over a theoretical 100-turbine wind farm, these changes could lead to instantaneous power prediction gains or losses equivalent to the addition or loss of multiple utility-scale turbines. At this site, REWS is the most useful metric for segregating the turbine's power curve into high and low cases of power production when compared to the other shear or stability metrics. Therefore, REWS enables improved forecasts of power production.
Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
National Science Foundation (NSF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1677496
Report Number(s):
NREL/JA--5000-78107; MainId:32016; UUID:fd0d84aa-282a-44ac-a3b4-c2fa0f8bc00b; MainAdminID:18705
Journal Information:
Wind Energy Science (Online), Journal Name: Wind Energy Science (Online) Journal Issue: 3 Vol. 5; ISSN 2366-7451
Publisher:
European Wind Energy Association - CopernicusCopyright Statement
Country of Publication:
United States
Language:
English

References (47)

Wind Resource Assessment book May 2012
Nocturnal wind-directional shear in complex terrain: Nocturnal Wind-Directional Shear journal April 2014
Influence of a valley exit jet on the nocturnal atmospheric boundary layer at the foothills of the Pyrenees
  • Jiménez, Maria A.; Cuxart, Joan; Martínez-Villagrasa, Daniel
  • Quarterly Journal of the Royal Meteorological Society, Vol. 145, Issue 718 https://doi.org/10.1002/qj.3437
journal January 2019
On wind turbine power performance measurements at inclined airflow journal July 2004
A spinner-integrated wind lidar for enhanced wind turbine control: Spinner-integrated wind lidar for enhanced steering and control journal October 2012
A new formulation for rotor equivalent wind speed for wind resource assessment and wind power forecasting: New formulation for equivalent wind speed journal September 2015
Demonstrating the effect of vertical and directional shear for resource mapping of wind power: Demonstrating the effect of vertical and directional shear for resource mapping of wind power journal November 2015
Properties of the offshore low level jet and rotor layer wind shear as measured by scanning Doppler Lidar: Offshore low level jet from scanning doppler lidar measurements journal December 2016
Classifying rotor-layer wind to reduce offshore available power uncertainty: Classifying rotor-layer wind to reduce offshore available power uncertainty journal March 2018
Do we really need rotor equivalent wind speed? journal March 2019
Wind turbine power and sound in relation to atmospheric stability journal January 2008
The influence of the wind speed profile on wind turbine performance measurements journal May 2009
Assessing atmospheric stability and its impacts on rotor-disk wind characteristics at an onshore wind farm journal July 2011
Diurnal variation of the dry overland boundary layer vertical temperature profile journal December 2009
A nocturnal low level jet during PUKK journal February 1985
Steady state hodographs in a baroclinic boundary layer journal December 1971
Analysis of the turbulence structure of a marine low-level jet journal October 1993
Observing and Simulating Wind-Turbine Wakes During the Evening Transition journal May 2017
Wind turbulence and atmospheric stability — Their effect on wind turbine output journal January 1999
A stochastic framework for the grid integration of wind power using flexible load approach journal December 2014
Advance measurement of gusts by laser anemometry journal December 2007
Improving grid integration of wind turbines by using secondary batteries journal June 2014
Nocturnal Low-Level Jet Characteristics Over Kansas During Cases-99 journal November 2002
U.S. East Coast Lidar Measurements Show Offshore Wind Turbines Will Encounter Very Low Atmospheric Turbulence journal May 2019
Field-test results using a nacelle-mounted lidar for improving wind turbine power capture by reducing yaw misalignment journal June 2014
Atmospheric stability affects wind turbine power collection journal January 2012
The modification of wind turbine performance by statistically distinct atmospheric regimes journal September 2012
Effects of complex wind regimes and meteorlogical parameters on wind turbine performances conference May 2012
Wind Integration in Power Systems: Operational Challenges and Possible Solutions journal January 2011
Influence of Atmospheric Stability on Wind Turbine Power Performance Curves journal February 2006
Speed and Direction Shear in the Stable Nocturnal Boundary Layer journal January 2009
Boundary Layer Wind Maxima and Their Significance for the Growth of Nocturnal Inversions journal May 1957
Forecasting the Wind to Reach Significant Penetration Levels of Wind Energy journal September 2011
The Perdigão: Peering into Microscale Details of Mountain Winds journal May 2019
The Second Wind Forecast Improvement Project (WFIP2): Observational Field Campaign journal September 2019
Observing and Simulating the Summertime Low-Level Jet in Central Iowa journal June 2015
Incorporation of the Rotor-Equivalent Wind Speed into the Weather Research and Forecasting Model’s Wind Farm Parameterization journal March 2019
The diurnal variation of the marine surface wind in an offshore flow journal July 2005
Wind Shear and Uncertainties in Power Curve Measurement and Wind Resources journal October 2009
Modified Power Curves for Prediction of Power Output of Wind Farms journal May 2019
Effects of Yaw Error on Wind Turbine Running Characteristics Based on the Equivalent Wind Speed Model journal June 2015
Global distribution and seasonal variability of coastal low-level jets derived from ERA-Interim reanalysis journal May 2013
Spatial and temporal variability of turbulence dissipation rate in complex terrain journal January 2019
Wind turbine power production and annual energy production depend on atmospheric stability and turbulence journal January 2016
Determination of optimal wind turbine alignment into the wind and detection of alignment changes with SCADA data journal January 2018
Initial results from a field campaign of wake steering applied at a commercial wind farm – Part 1 journal January 2019
The effect of wind direction shear on turbine performance in a wind farm in central Iowa journal January 2020

Figures / Tables (19)

Figure 1(p. 3)figure Figure 1
Figure 2(p. 4)figure Figure 2
Figure 3(p. 6)figure Figure 3
Figure 4(p. 6)figure Figure 4
Figure 5(p. 6)figure Figure 5
Figure 6(p. 7)figure Figure 6
Figure 7(p. 8)figure Figure 7
Figure 8(p. 10)figure Figure 8
Table 1(p. 10)table Table 1
Table 2(p. 11)table Table 2
Figure 9(p. 12)figure Figure 9
Figure 10(p. 13)figure Figure 10
Figure 11(p. 14)figure Figure 11
Figure 12(p. 15)figure Figure 12
Figure 13(p. 16)figure Figure 13
Figure 14(p. 16)figure Figure 14
Figure 15(p. 17)figure Figure 15
Figure 16(p. 17)figure Figure 16
Figure 17(p. 18)figure Figure 17

Similar Records

Wind Shear and Wind Veer Effects on Wind Turbines
Book · Tue Jan 25 23:00:00 EST 2022 · OSTI ID:1983883
Incorporation of the Rotor-Equivalent Wind Speed into the Weather Research and Forecasting Model’s Wind Farm Parameterization
Journal Article · Mon Mar 11 20:00:00 EDT 2019 · Monthly Weather Review · OSTI ID:1507679
How Does Inow Veer Affect the Veer of a Wind-Turbine Wake?
Journal Article · Mon Mar 02 19:00:00 EST 2020 · Journal of Physics. Conference Series · OSTI ID:1659946

Related Subjects

17 WIND ENERGY
directional veer
turbine
wind energy
wind speed shear