X-Wakes

Interaction between the Wakes of Large Offshore Wind Farms and Wind Farm Clusters with the Marine Atmospheric Boundary Layer

Offshore wind energy has a central role to play in terms of the energy supply with renewable energies. Given the limited amount of usable space, offshore wind farms are set up in so-called clusters. As a result, wind farms and the individual turbines interact. Wakes with low wind speeds and considerable turbulence develop in the wind shadow downstream of the turbines. The aim of the X-Wakes project is to understand the current and future changes in wind conditions with the ongoing  expansion of large scale offshore wind farm developments.

Project leader:
Dr. Martin Dörenkämper (Project Coordination), Dr. Astrid Lampert (Scientific Spokesperson)

Duration of the project:
01.11.2019 – 30.04.2023

Contract number of the project:
03EE3008A

Problems/Questions/Key aspects/Aims of the project

  • The aim of the X-Wakes project is to investigate changes in wind conditions for the operation of large offshore wind farm clusters.
  • In the X-Wakes project data are collected using various measurement methods, including LiDAR, unmanned and manned aircraft and satellites.
  • With the help of these data, the project aims to validate advanced tools for the accurate mapping of large wind farm areas in industry models and hi-fidelity wind farm flow and weather models.
  • Besides the investigation of the interaction of the wake of several wind farms among each other, the interaction of large scale wakes with the marine atmospheric boundary layer and also coastal effects are studied.

The Federal Government’s plans for the energy revolution in Germany foresees a share of at least 80 percent of the gross electricity consumption being covered by renewable energies by 2050. Offshore wind energy is a fundamental pillar here. However, the space available for wind energy in the German Bight is limited, which is why wind farms are mostly built in clusters. Such clusters can comprise several hundred wind turbines. Wakes with low wind speeds and considerable turbulence develop in the wind shadow behind the turbines. Under certain atmospheric conditions, these wakes can extend for distances in excess of 50 kilometers.

In the framework of  X-Wakes wakes and other accumulative effects such as the global blockage effect are investigated to understand how the wind farm clusters influence each other as well as what consequences a large-scale expansion of the offshore wind farm will have on wind conditions in the future. Computer models will be enhanced using the results from this project in order to be able to predict the yields of the wind farms for future expansion scenarios under realistic conditions.

The researchers are employing a combination of complimentary methods. Stationary LiDAR measurements at different locations in the German Bight deliver meteorological data continuously. The extent of the wakes is analyzed on a large scale with the aid of satellite-based remote sensing data. Measuring campaigns with a research aircraft at low altitude also deliver high-resolution meteorological data.

The associated partners of the project provide information for planning the further expansion of the German Bight as well as valuable wind farm production data to ensure that the project objectives are aligned with current and future wind farm operation.

Project Coordination:
Fraunhofer IWES, Dr. Martin Dörenkämper

Scientific Spokesperson:
TU Braunschweig, Dr. Astrid Lampert

 

Contacts and Partners

Dr. Martin Dörenkämper (Project Coordination)
 +49 441 798 5014
 martin.doerenkaemper@iwes.fraunhofer.de

Further Funded Partners:

Karlsruhe Institute for Technology
ForWind – Carl von Ossietzky University Oldenburg
Eberhard Karls University Tübingen
Helmholtz-Zentrum Geesthacht Center for Materials and Coastal Research
UL International GmbH

Associated Partners:

Federal Maritime and Hydrographic Agency, German Weather Service, EnBW, Merkur Offshore, Nordsee One, Ørsted, RWE Renewables, TenneT, Trianel, Vattenfall

Publications

Here you can find interesting presentations about this project in our RAVE International Workshops.

RAVE Workshop 2020: presentation 8

(Only available in German) "Interaktion der Nachläufe großer Offshore-Windparks und Windparkcluster mit der marinen atmosphärischen Grenzschicht" / Dr. Tom Neumann und Dr. Martin Dörenkämper

RAVE Workshop 2021: presentation 8

"Measuring large scale offshore wind farm effects with scanning lidar" / Jörge Schneemann

RAVE Workshop 2023: presentation

"X-Wakes: Recent Results from Modelling and Measurements of Large Scale Wakes in Interaction with the Marine Atmospheric Boundary Layer" / Dr. Martin Dörenkämper

 

In addition, you will find further peer-reviewed publications originating from the X-Wakes project under the following links:

Cañadillas, B., Beckenbauer, M., Trujillo, J. J., Dörenkämper, M., Foreman, R., Neumann, T., and Lampert, A.: Offshore wind farm cluster wakes as observed by long-range-scanning wind lidar measurements and mesoscale modeling, Wind Energ. Sci., 7, 1241–1262, https://doi.org/10.5194/wes-7-1241-2022, 2022.

Cañadillas, B., Wang, S., Ahlert, Y., Djath, B., Barekzai, M., Foreman, R., and Lampert, A.: Coastal horizontal wind speed gradients in the North Sea based on observations and ERA5 reanalysis data, Meteorologische Zeitschrift, DOI 10.1127/metz/2022/1166, 22 pp., 2023.

Kemme, L., Strnad, S., Vollmer, L., Schmidt, J., and Lukassen, L.J.: Sensitivity of Wake Modelling Setups, J. Phys.: Conf. Ser. 2265, 022007, https://doi.org/10.1088/1742-6596/2265/2/022007 , 2022.

von Brandis, A., Centurelli, G., Schmidt, J., Vollmer, L., Djath, B., and Dörenkämper, M.: An investigation of spatial wind direction variability and its consideration in engineering models, Wind Energ. Sci., 8, 589–606, https://doi.org/10.5194/wes-8-589-2023, 2023.

Rausch, T., Schuchard, M., Cañadillas, B., and Lampert, A.: One year measurements of vertical profiles of wind speed and wind direction from 40 to 500 m at Heligoland, German Bight, North Sea, Germany. Technische Universität Braunschweig, PANGAEA, https://doi.org/10.1594/PANGAEA.924184, 2020.

Rausch, T., Cañadillas, B., Hampel, O., Simsek, T., Tayfun, Y.B., Neumann, T., Siedersleben, S., Lampert, A.: Wind Lidar and Radiosonde Measurements of Low-Level Jets in Coastal Areas of the German Bight, Atmosphere, 13, 839. https://doi.org/10.3390/atmos13050839, 2022.

Rausch, T., Bärfuss, K., Hankers, R., Bitter, M., Feuerle, T., Cremer, M., Angermann, M., Füllgraf, J., and Lampert, A.:  In-situ airborne measurements of atmospheric and sea surface parameters related to offshore wind parks in the German Bight, PANGAEA, https://doi.org/10.1594/PANGAEA.955382, 2023.

Rausch, T., Cañadillas, B., and Lampert, A.: Coastal vertical wind lidar measurements of horizontal wind speed and wind direction from 40 to 500 m at Norderney island, German Bight, North Sea, Germany. PANGAEA, https://doi.org/10.1594/PANGAEA.953770, 2023.

Schulz-Stellenfleth, J., Emeis, S., Dörenkämper, M., Bange, J., Cañadillas, B., Neumann, T., Schneemann, J., Weber, I., zum Berge, K., Platis, A., Djath, B., Gottschall, J., Vollmer, L., Rausch, T., Barekzai, M., Hammel, J., Steinfeld, G., Lampert, A.: Coastal impacts on offshore wind farms – a review focussing on the German Bight area, Meteorol. Zeitschrift, 31 (4), 289-315,. https://doi.org/10.1127/metz/2022/1109, 2022.

Centurelli, G., Vollmer, L., Schmidt, J., Dörenkämper, M., Schröder, M., Lukassen, L., and Peinke, J.: Evaluating Global Blockage engineering parametrizations with LES, J. Phys.: Conf. Ser., 1934, 012 021, https://doi.org/10.1088/1742-6596/1934/1/012021 , 2021.

Schneemann, J., Theuer, F., Rott, A., Dörenkämper, M., and Kühn, M.: Offshore wind farm global blockage measured with scanning lidar, Wind Energ. Sci., 6, 521–538, https://doi.org/10.5194/wes-6-521-2021, 2021.

Vollmer, L., Sengers, B. A. M., and Dörenkämper, M.: Brief communication: A simple axial induction modification to WRF’s Fitch wind farm parameterisation, Wind Energ. Sci. Discuss. [preprint], https://doi.org/10.5194/wes-2023-89, in review, 2023.

 

X-Wakes final public workshop 26th June 2023

After conclusion of the BMWK-funded RAVE project "X-Wakes", a final public workshop took place on 26/06/2023. The workshop was conducted virtually and there were interesting presentations on the results of the project. The presentations can be downloaded here:

  • X-Wakes Logo ©Fraunhofer IWES
  • Picture 1: Research aircraft flying at low altitude delivers high-resolution meteorological data © Mark Bittner / TU Braunschweig
  • Picture 2: Stationary LiDAR measuring buoys deliver meteorological data continuously © Jörge Schneemann, ForWind – Uni Oldenburg