The Wind Forecast Improvement Project (WFIP): A Public–Private Partnership Addressing Wind Energy Forecast Needs

Wilczak, James M.; Finley, Catherine A.; Freedman, Jeff; Cline, J. D.; Bianco, L.; Olson, Joseph B.; Djalalova, Irina V.; Sheridan, Lindsay; Ahlstrom, Mark; Manobianco, John; Zack, John W.; Carley, Jacob R.; Benjamin, Stanley G.; Coulter, R. L.; Berg, Larry K.; Mirocha, Jeffrey D.; Clawson, K. L.; Natenberg, Edward; Marquis, Melinda

doi:10.1175/bams-d-14-00107.1

Cited by 95 publications

(79 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, this study lays the groundwork for future investigations to compare the power output of the WFP scheme to the observed power production, which can be conducted with nacelle anemometer measurements (St. Martin et al 2017). Since mesoscale modelling is crucial in predicting power production in wind farms (Marquis et al 2011;Jiménez et al 2015;Wilczak et al 2015), comparisons of predicted and observed power output can help to identify areas for improvement in the WFP scheme in the WRF model. Moreover, accurate representation of wind farms in numerical weather prediction models is important for both simulating windenergy production and planning for energy infrastructure (Jacobson et al 2015;MacDonald et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Observing and Simulating Wind-Turbine Wakes During the Evening Transition

Lee

Lundquist

2017

Boundary-Layer Meteorol

View full text Add to dashboard Cite

Wind-turbine-wake evolution during the evening transition introduces variability to wind-farm power production at a time of day typically characterized by high electricity demand. During the evening transition, the atmosphere evolves from an unstable to a stable regime, and vertical stratification of the wind profile develops as the residual planetary boundary layer decouples from the surface layer. The evolution of wind-turbine wakes during the evening transition is examined from two perspectives: wake observations from single turbines, and simulations of multiple turbine wakes using the mesoscale Weather Research and Forecasting (WRF) model. Throughout the evening transition, the wake's wind-speed deficit and turbulence enhancement are confined within the rotor layer when the atmospheric stability changes from unstable to stable. The height variations of maximum upwind-downwind differences of wind speed and turbulence intensity gradually decrease during the evening transition. After verifying the WRF-model-simulated upwind wind speed, wind direction and turbulent kinetic energy profiles with observations, the wind-farm-scale wake evolution during the evening transition is investigated using the WRF-model wind-farm parametrization scheme. As the evening progresses, due to the presence of the wind farm, the modelled hub-height wind-speed deficit monotonically increases, the relative turbulence enhancement at hub height grows by 50%, and the downwind surface sensible heat flux increases, reducing surface cooling. Overall, the intensifying wakes from upwind turbines respond to the evolving atmospheric boundary layer during the evening transition, and undermine the power production of downwind turbines in the evening.

show abstract

Section: Discussionmentioning

confidence: 99%

Observing and Simulating Wind-Turbine Wakes During the Evening Transition

Lee

Lundquist

2017

Boundary-Layer Meteorol

View full text Add to dashboard Cite

show abstract

“…Nocturnal low-level jets (LLJs; [47][48][49][50][51]) occur frequently over this region. These LLJs and associated wind speed maxima are one of the most important reasons for the abundance of wind farms, as well as significant nighttime wind power production, over this region [52][53][54].…”

Section: Low-level Jetsmentioning

confidence: 99%

Buoyancy effects on the scaling characteristics of atmospheric boundary-layer wind fields in the mesoscale range

Kiliyanpilakkil¹,

Basu²,

Ruiz-Columbie³

et al. 2015

Phys. Rev. E

View full text Add to dashboard Cite

We have analyzed long-term wind speed time-series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend on height. This anomalous behavior is likely caused by the buoyancy effects. In the framework of the extended self-similarity, the relative scaling exponents portray quasi-universal behavior.

show abstract

“…They are particularly important due to their role in the formation of the climate and their impacts on the production of wind energy. Wilczak et al (2015) determined that LLJs drive wind farm capacity factors to over 60 % during the nocturnal hours. Thus, they are beneficial for the wind energy production; however, it is not totally clear what their influence is in terms of the turbine's structure.…”

Section: Introductionmentioning

confidence: 99%

Impacts of the low-level jet's negative wind shear on the wind turbine

et al. 2017

View full text Add to dashboard Cite

Abstract.Nocturnal low-level jets (LLJs) are defined as relative maxima in the vertical profile of the horizontal wind speed at the top of the stable boundary layer. Such peaks constitute major power resources for wind turbines. However, a wind speed maximum implies a transition from positive wind shears below the peak to negative ones above. The effect that such a transition has on wind turbines has not been thoroughly studied.This research study employed a methodical approach to the study of negative wind shear's impacts on wind turbines. Up to now, the presence of negative shears inside the turbine's rotor in relation to the presence of positive shears has been largely ignored. A parameter has been proposed to quantify that presence in future studies of LLJ-wind-turbine interactions. Simulations were performed using the NREL aeroelastic simulator FAST code. Rather than using synthetic profiles to generate the wind data, all simulations were based on real data captured at the high frequency of 50 Hz, which allowed us to perform the analysis of a turbine's impacts with real-life, small scales of wind motions.It was found that the presence of negative wind shears at the height of the turbine's rotor appeared to exert a positive impact on reducing the motions of the nacelle and the tower in every direction, with oscillations reaching a minimum when negative shears covered the turbine swept area completely. Only the tower wobbling in the spanwise direction was amplified by the negative shears; however, this occurred at the tower's slower velocities and accelerations. The forces and moments were also reduced by the negative shears. The aforementioned impacts were less beneficial in the rotating parts, such as the blades and the shafts. Finally, the variance in power production was also reduced. These findings can be very important for the next generation of wind turbines as they reach deeper into LLJ's typical heights.The study demonstrated that the presence of negative shears is significant in reducing the loading on wind turbines. A major conclusion of this study is that the wind turbines of the future should probably be designed with the aim of reaching the top of the nightly boundary layer more often and therefore the altitudes where negative shears are more frequent. Doing so will help to reduce the positive shear's associated damage and to capture the significant LLJ energy.

show abstract

The Wind Forecast Improvement Project (WFIP): A Public–Private Partnership Addressing Wind Energy Forecast Needs

Cited by 95 publications

References 27 publications

Observing and Simulating Wind-Turbine Wakes During the Evening Transition

Observing and Simulating Wind-Turbine Wakes During the Evening Transition

Buoyancy effects on the scaling characteristics of atmospheric boundary-layer wind fields in the mesoscale range

Impacts of the low-level jet's negative wind shear on the wind turbine

Contact Info

Product

Resources

About