Wake effects between two neighbouring wind farms

Nygaard, Nicolai; Hansen, Sidse Damgaard

doi:10.1088/1742-6596/753/3/032020

Cited by 53 publications

(47 citation statements)

References 9 publications

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“…Most offshore observational studies have so far generally focused on the wind and power deficit observed in and downwind of large wind farms (e.g. Barthelmie et al 2010, Nygaard 2014, Nygaard and Hansen 2016 except Foreman et al (2017). Only few studies have investigated the potential effect of wind Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.…”

Section: Introductionmentioning

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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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: Introductionmentioning

confidence: 99%

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

Siedersleben

Lundquist

Platis

et al. 2018

Environ. Res. Lett.

106

View full text Add to dashboard Cite

show abstract

“…Many studies of wake effects around large offshore wind farms are focused on wake interaction within the wind farms or between closely adjacent wind farms (Barthelmie et al, 2010;Hansen et al, 2012Hansen et al, , 2015Nygaard 2014;Volker et al, 2015;Nygaard and Hansen 2016). Investigations of wind farm wake effects based on SAR wind maps have revealed the existence of extensive wakes under certain atmospheric conditions (Christiansen and Hasager 2005;Christiansen et al, 2006;Li and Lehner 2013;Hasager et al, 2015b).…”

Section: Introductionmentioning

confidence: 99%

“…Good results are obtained in the open sea but in coastal regions near upstream land mass the uncertainty increases . Wind farm wakes are not simulated by NWP models unless the effect of wind turbines to the atmospheric flow are parameterized (Fitch et al, 2012;Volker et al, 2015) Engineering wind farm models like the Park model (Jensen, 1983), Fuga (Ott et al, 2011), and the Gunnar C. Larsen model (Larsen, 2009) have been used in combination with WRF outputs (Peña et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Applications of satellite winds for the offshore wind farm site Anholt

et al. 2018

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Abstract. Rapid growth in the offshore wind energy sector means more offshore wind farms are placed closer to each other and in the lee of large land masses. Synthetic aperture radar (SAR) offers maps of the wind speed offshore with high resolution over large areas. These can be used to detect horizontal wind speed gradients close to shore and wind farm wake effects. SAR observations have become much more available with the free and open-access data from European satellite missions through Copernicus. Examples of applications and tools for using large archives of SAR wind maps to aid offshore site assessment are few. The Anholt wind farm operated by the utility company Ørsted is located in coastal waters and experiences strong spatial variations in the mean wind speed. Wind speeds derived from the Supervisory Control And Data Acquisition (SCADA) system are available at the turbine locations for comparison with winds retrieved from SAR. The correlation is good, both for free-stream and waked conditions. Spatial wind speed variations along the rows of wind turbines derived from SAR wind maps prior to the wind farm construction agree well with information gathered by the SCADA system and a numerical weather prediction model. Wind farm wakes are detected by comparisons between images before and after the wind farm construction. SAR wind maps clearly show wakes for long and constant fetches but the wake effect is less pronounced for short and varying fetches. Our results suggest that SAR wind maps can support offshore wind energy site assessment by introducing observations in the early phases of wind farm projects.

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“…For offshore wind farms, wakes are responsible for the largest single loss of energy production. Considerable effort is therefore being put to the analysis and modelling of wake effects [1][2][3][4][5][6][7][8][9]. Normally, the wakes are invisible, discernible only through the reduced production of downstream turbines caught in the wakes.…”

Section: Introductionmentioning

confidence: 99%

Wind Farm Wake: The 2016 Horns Rev Photo Case

et al. 2017

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Offshore wind farm wakes were observed and photographed in foggy conditions at Horns Rev 2 on 25 January 2016 at 12:45 UTC. These new images show highly contrasting conditions regarding the wind speed, turbulence intensity, atmospheric stability, weather conditions and wind farm wake development as compared to the Horns Rev 1 photographs from 12 February 2008. The paper examines the atmospheric conditions from satellite images, radiosondes, lidar and wind turbine data and compares the observations to results from atmospheric meso-scale modelling and large eddy simulation. Key findings are that a humid and warm air mass was advected from the southwest over cold sea and the dew-point temperature was such that cold-water advection fog formed in a shallow layer. The flow was stably stratified and the freestream wind speed was 13 m/s at hub height, which means that most turbines produced at or near rated power. The wind direction was southwesterly and long, narrow wakes persisted several rotor diameters downwind of the wind turbines. Eventually mixing of warm air from aloft dispersed the fog in the far wake region of the wind farm.

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Wake effects between two neighbouring wind farms

Cited by 53 publications

References 9 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

Applications of satellite winds for the offshore wind farm site Anholt

Wind Farm Wake: The 2016 Horns Rev Photo Case

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