The top-down model of wind farm boundary layers and its applications

Meneveau, Charles

doi:10.1080/14685248.2012.663092

Cited by 68 publications

(107 citation statements)

References 19 publications

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“…Model performance could be evaluated using real-world terrain and weather, though the use of nested LES domains in such configurations presents added challenges such as how to properly spin-up turbulence [Muñoz-Esparza et al, 2014]. Increased computing power would enable simulation of large LES wind farms, which could be used to evaluate wind-farm boundary layers deep within expansive arrays [Meneveau, 2012]. Of course, additional observation of wind-farm wake behavior could inform development of both techniques.…”

Section: Discussionmentioning

confidence: 99%

Simulating effects of a wind‐turbine array using LES and RANS

Vanderwende

Kosović

Lundquist

et al. 2016

J Adv Model Earth Syst

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Growth in wind power production has motivated investigation of wind‐farm impacts on in situ flow fields and downstream interactions with agriculture and other wind farms. These impacts can be simulated with both large‐eddy simulations (LES) and mesoscale wind‐farm parameterizations (WFP). The Weather Research and Forecasting (WRF) model offers both approaches. We used the validated generalized actuator disk (GAD) parameterization in WRF‐LES to assess WFP performance. A 12‐turbine array was simulated using the GAD model and the WFP in WRF. We examined the performance of each scheme in both convective and stable conditions. The GAD model and WFP produced qualitatively similar wind speed deficits and turbulent kinetic energy (TKE) production across the array in both stability regimes, though the magnitudes of velocity deficits and TKE production levels were underestimated and overestimated, respectively. While wake growth slowed in the latter half of the WFP array as expected, wakes did not approach steady state by the end of the array as simulated by the GAD model. A sensitivity test involving the deactivation of explicit TKE production by the WFP resulted in turbulence levels within the array well that were below those produced by the GAD in both stable and unstable conditions. Finally, the WFP overestimated downwind power production deficits in stable conditions because of the lack of wake stabilization in the latter half of the array.

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Section: Discussionmentioning

confidence: 99%

Simulating effects of a wind‐turbine array using LES and RANS

Vanderwende

Kosović

Lundquist

et al. 2016

J Adv Model Earth Syst

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“…When considering the much greater installed capacity of 5.0 MW i ·km −2 , the 11 GW of horizontal kinetic energy flux would be fully consumed within a downwind depth of about 10 km (see also ref. 22). Therefore, as the downwind extent of the wind farm grows, electricity generation rates of successive downwind turbines are derived progressively less from the horizontal flux and more from the vertical flux.…”

Section: Discussionmentioning

confidence: 99%

“…10 and 11, where a thought experiment illustrated how considering only wind speeds and turbine specifications can yield generation rates that are physically unrealizable. The method is based on an analytical description of the momentum balance of the wind farm, a central concept used in similar studies on large-scale wind power limits (20)(21)(22) or for other forms of renewable energy such as tidal power (23,24) (detailed methodology is given in SI Appendix). It assumes that when wind farms extend tens of kilometers downwind, horizontal kinetic energy has either been extracted from the mean flow by the first few rows of turbines or has been lost to turbulent dissipation, so that the generation rate of wind turbines further downwind is then limited by the downward flux of kinetic energy.…”

Section: Methodsmentioning

confidence: 99%

Two methods for estimating limits to large-scale wind power generation

Miller

Brunsell

Mechem

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Wind turbines remove kinetic energy from the atmospheric flow, which reduces wind speeds and limits generation rates of large wind farms. These interactions can be approximated using a vertical kinetic energy (VKE) flux method, which predicts that the maximum power generation potential is 26% of the instantaneous downward transport of kinetic energy using the preturbine climatology. We compare the energy flux method to the Weather Research and Forecasting (WRF) regional atmospheric model equipped with a wind turbine parameterization over a 10 5 km 2 region in the central United States. The WRF simulations yield a maximum generation of 1.1 W e ·m −2 , whereas the VKE method predicts the time series while underestimating the maximum generation rate by about 50%. Because VKE derives the generation limit from the preturbine climatology, potential changes in the vertical kinetic energy flux from the free atmosphere are not considered. Such changes are important at night when WRF estimates are about twice the VKE value because wind turbines interact with the decoupled nocturnal low-level jet in this region. Daytime estimates agree better to 20% because the wind turbines induce comparatively small changes to the downward kinetic energy flux. This combination of downward transport limits and wind speed reductions explains why large-scale wind power generation in windy regions is limited to about 1 W e ·m −2 , with VKE capturing this combination in a comparatively simple way.generation limits | turbine-atmosphere interactions | wind resource | kinetic energy flux | extraction limits W ind power has progressed from being a minor source of electricity to a technology that accounted for 3.3% of electricity generation in the United States and 2.9% globally in 2011 (1, 2). Combined with an increase in quantity, the average US wind turbine also changed from 2001 to 2012; hub height increased by 40%, rotor-swept area increased by 180%, and rated capacity increased by 100% (2). Likely a combination of both the above-noted technological innovations and improved siting, the per-turbine capacity factor, the ratio of the electricity generation rate (MW e ) to the rated capacity (MW i ), increased globally from 17% in 2001 to 29% in 2012 (1, 2), making a recently deployed wind farm likely to generate about 70% more electricity from the same installed capacity.Combining climate datasets with these observed trends of greater-rated capacities and capacity factors, several academic and government research studies estimate large-scale wind power electricity generation rates of up to 7 W e ·m −2 (3-7). However, a growing body of research suggests that as larger wind farms cover more of the Earth's surface, the limits of atmospheric kinetic energy generation, downward transport, and extraction by wind turbines limits large-scale electricity generation rates in windy regions to about 1.0 W e ·m −2 (8-14). Ideally, these inherent atmospheric limitations to generating electricity with wind power could be considered without scenario-and technol...

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“…As wind energy is gaining more and more interest for its ability to produce clean, affordable and reliable electricity [1,2], modeling and simulations of large wind farms are becoming an important subject [3,4,5], especially for offshore applications. Actuator disk models are often used in such large wind farm modeling and simulations [3,5,6].…”

Section: Introductionmentioning

confidence: 99%