Evaluation of a Wind Farm Parametrization for Mesoscale Atmospheric Flow Models with Aircraft Measurements

Siedersleben, Simon; Platis, Andreas; Lundquist, Julie K.; Lampert, Astrid; Bärfuss, Konrad; Cañadillas, Beatriz; Djath, Bughsin; Schulz‐Stellenfleth, Johannes; Bange, Jens; Neumann, Thomas; Emeis, Stefan

doi:10.1127/metz/2018/0900

Cited by 94 publications

(63 citation statements)

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“…Therefore, we use the coefficients of the wind turbine Siemens SWT3.6-120-onshore as these are available (http://wind-turbine-models.com/ turbines/646-siemens-swt-3.6-120-shore (30 October 2018)). We have shown in Siedersleben et al (2018) that the errors introduced by these uncertainties have only a marginal effect on the wake effect.…”

Section: Numerical Simulationsmentioning

confidence: 88%

“…The numerical setup and the parameterizations in this study are the same as in Siedersleben et al (2018); the reader is referred to this paper for full details. Numerical simulations are performed with Weather Research and Forecasting model WRF3.8.1 (Skamarock et al 2008) with three domains having a resolution of 15, 5 and 1.67 km (figure 1), resulting in up to six wind turbines per grid cell.…”

Section: Numerical Simulationsmentioning

confidence: 99%

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Micrometeorological impacts of offshore wind farms as seen in observations and simulations

Siedersleben

Lundquist

Platis

et al. 2018

Environ. Res. Lett.

106

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In Europe, offshore wind farms have a capacity of 16 GW, with 71% installed at the North Sea. These wind farms represent an additional source of turbulence and may influence the stratification of the marine boundary layer. We present aircraft measurements and simulations showing an impact on temperature and humidity at hub height in the order of 0.5 K and 0.5gkg −1 even 60 km downwind of a wind farm cluster. We extend these simulations to explore a realistic future scenario, suggesting wakes in potential temperature and water vapor propagating more than 100 km downwind. Such impacts of wind farms are only observed in case of a strong stable stratification at rotor height, allowing wind farms to mix warmer air downward.

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Section: Numerical Simulationsmentioning

confidence: 88%

Section: Numerical Simulationsmentioning

confidence: 99%

Micrometeorological impacts of offshore wind farms as seen in observations and simulations

Siedersleben

Lundquist

Platis

et al. 2018

Environ. Res. Lett.

106

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“…Offshore wind power plant wakes can extend tens of km downwind (Platis et al, ; Siedersleben, Platis, et al, ; Siedersleben, Lundquist et al, ) in low‐turbulence, stably stratified conditions. These wakes undermine offshore power production (Nygaard, ).…”

Section: Discussionmentioning

confidence: 99%

“…Offshore ϵ has, on average, smaller values compared to those found in comparable studies onshore, with a weak diurnal cycle. The small average values of ϵ are conducive to strong and long‐lived wakes such as wakes observed in stable stratification in the North Sea (Platis et al, ; Siedersleben, Lundquist et al, ; Siedersleben, Platis, et al, ). Moreover, this extended persistence of wakes will occur throughout the diurnal cycle, given the absence of strong turbulence dissipation even in convective daytime conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Turbulence also plays a key role in the development and subsequent erosion of wind turbine and wind farm wakes, whose spatial extent can be particularly long offshore (Platis et al, ; Siedersleben, Lundquist et al, ; Siedersleben, Platis, et al, ), with observed wakes extending beyond 45 km in some cases. While the erosion of wakes is related to ambient turbulent kinetic energy, the dissipation of turbulence within the wake, which represents the first step of wake erosion, is defined by the turbulence dissipation rate.…”

Section: Introductionmentioning

confidence: 99%

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U.S. East Coast Lidar Measurements Show Offshore Wind Turbines Will Encounter Very Low Atmospheric Turbulence

Bodini

Lundquist

Kirincich

2019

Geophysical Research Letters

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The rapid growth of offshore wind energy requires accurate modeling of the wind resource, which can be depleted by wind farm wakes. Turbulence dissipation rate (ϵ) governs the accuracy of model predictions of hub‐height wind speed and the development and erosion of wakes. Here we assess the variability of turbulence kinetic energy and ϵ using 13 months of observations from a profiling lidar deployed on a platform off the Massachusetts coast. Offshore, ϵ is 2 orders of magnitude smaller than onshore, with a subtle diurnal cycle. Wind direction influences the annual cycle of turbulence, with larger values in winter when the wind flows from the land, and smaller values in summer, when the wind flows from open ocean. Because of the weak turbulence, wind plant wakes will be stronger and persist farther downwind in summer.

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Offshore wind farm wake recovery: Airborne measurements and its representation in engineering models

Cañadillas¹,

Foreman²,

Barth³

et al. 2020

Wind Energy

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We present an analysis of wind measurements from a series of airborne campaigns conducted to sample the wakes from two North Sea wind farm clusters, with the aim of determining the dependence of the downstream wind speed recovery on the atmospheric stability. The consequences of the stability dependence of wake length on the expected annual energy yield of wind farms in the North Sea are assessed by an engineering model. Wakes are found to extend for significantly longer downstream distances (>50 km) in stable conditions than in neutral and unstable conditions (<15 km). The parameters of one common engineering model are modified to reproduce the observed wake decay at downstream distances >30 km. More significant effects on the energy yield are expected for wind farms separated by distances <30 km, which is generally the case in the North Sea, but additional data would be required to validate the suggested parameter modifications within the engineering model. A case study is accordingly performed to show reductions in the farm efficiency downstream of a wind farm. These results emphasize not only the importance of understanding the impact of atmospheric stability on offshore wind farms but also the need to update the representation of wakes in current industry models to properly include wake-induced energy losses, especially in large offshore clusters. KEYWORDS atmospheric stability, offshore wind farm cluster, wake recovery, wind farm efficiency

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Evaluation of a Wind Farm Parametrization for Mesoscale Atmospheric Flow Models with Aircraft Measurements

Cited by 94 publications

References 0 publications

Micrometeorological impacts of offshore wind farms as seen in observations and simulations

Micrometeorological impacts of offshore wind farms as seen in observations and simulations

U.S. East Coast Lidar Measurements Show Offshore Wind Turbines Will Encounter Very Low Atmospheric Turbulence

Offshore wind farm wake recovery: Airborne measurements and its representation in engineering models

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