DRI Faculty:    Darko Koracin | Richard Reinhardt | Greg McCurdy | Travis McCord

Collaborators: none

Objectives/Methods: The objective of this work effort was to characterize wind shear and turbulence for representative wind-developable areas in Nevada. This information and the models that provide it will be useful in specifying the appropriate technology and helping the developer choose the optimum orientation and spacing for a particular landscape.  A key element in this study is the measurement of turbulence at three levels above the ground (40, 60, and 80m) at the existing tower near Tonopah (Stone Cabin).  Most previous wind power density estimates are based on surface wind measurements and various extrapolation formulas, which are rarely verified, to provide estimates at hub heights.  In addition, the study will provide new insight into long-term statistics of turbulence at multiple levels that can be used to estimate its effects on turbine operation and maintenance.

Results/Conclusions: The study results showed that both community models (MM5 and WRF) are capable of capturing basic flow properties.  A spectrum of simultaneous horizontal model resolutions from 18km to 222m indicates that there is no firm conclusion that higher resolution automatically yields better results.  This is mainly due to the model complexity in physical parameterizations, which might not be appropriate for very high model resolutions.  Long-term (7 months) measurements by sonic anemometer showed much higher peaks in the turbulence kinetic energy (TKE) at all three levels than reported in the literature.  Simulated TKE is noticeably underestimated compared to sonic measurements, which might have a significant impact for turbine deployment at these elevations.  The empirical formulas to estimate winds at higher elevations based on the available standard heights (6 or 10m) have large errors compared with actual tower measurements. The evaluated model results can provide guidance on possible errors and uncertainties while estimating wind maps in this and other areas.

Presentations:

Koracin, D., R.L. Reinhardt, M. Liddle, T. McCord, D. Podnar, and T. Minor, 2007: Assessment of wind energy for Nevada using towers and mesoscale modeling.  Energy Sustainability 2007, 27-30 June, 2007, Long Beach, CA.

Koracin, D., R.L. Reinhardt, M. Liddle, T. McCord, D. Podnar, and T. Minor, 2007: Assessment of wind energy for Nevada using towers and mesoscale modeling.  2007 Annual Energy Symposium, 15-16 August, 2007, UNLV, Las Vegas.

Reports:

Koracin, D., R. Reinhardt, G. McCurdy, M. Liddle, T. McCord, R. Vellore, T. Minor, B. Lyles, D. Miller, and L. Ronchetti, "Wind Energy Assessment Study for Nevada - Tall Tower Deployment (Stone Cabin) 26 June 2005 - 31 December 2007" December 2009, NREL/SR-550-47085