Collecting new offshore wind facts

New collected observational data will be used to validate and improve numerical models and tools for i.e. weather forecasting, marine operations and wind farm layout optimization.

19.01.2016 by Gunn Janne Myrseth

Collecting new offshore wind facts

In the photo from left: A. Stephansen, K. G. Frøysa and M. Flügge. All having tasks in Trondheim tomorrow at the Deepwind conference. Photo: Head of Communication CMR, Gunn Janne Myrseth

How new facts about offshore wind is collected, will be presented by CMR-scientist Martin Flügge at the DeepWind conference 2016 in Trondheim tomorrow. He will go deep into the NORCOWE field campaign at the German met-mast FINO1 and talk about how NORCOWE scientists perform measurements of the atmospheric and upper ocean boundary-layer. But also collegues of Martin will attend. NORCOWE Centre Coordinator Annette Stephansen will be chair and NORCOWE manager Kristin Gulbrandsen Frøysa will be holding even more presentations. Frøysa will give two presentations ; Reference Wind Farm and Numerical reference wind farms.

FINO1

FINO1 is located in the North Sea approximately 45 km off the German island Borkum, and is situated in close vicinity to the first German offshore wind farm ‘Alpha Ventus’. The platform has an instrumented 100 met-mast where wind speed and wind direction, air- and water temperature, humidity and wave properties are recorded since autumn 2003. Its close location to the wind farm and the already 12 year long time-series of both meteorological and oceanographic parameters makes FINO1 an ideal research site for offshore wind.

The NORCOWE campaign is carried out by CMR in close collaboration with other NORCOWE partners, FuE Zentrum FH Kiel GmbH, Fraunhofer IWES, RAVE and ForWind.

The key purpose of the campaign is to improve our knowledge of the marine boundary-layer stability, turbulence generation processes in the water column and offshore wind turbine wake propagation effects. The collected observational data will be used to validate and improve numerical models and tools for i.e. weather forecasting, marine operations and wind farm layout optimization.  

Photo: CMR og NORCOWE

In order to provide a new and unique dataset for the study of offshore boundary-layer conditions in vicinity of a wind farm, simultaneously measurements of wind, temperature and humidity profiles in the marine atmospheric boundary layer are performed. On behalf of NORCOWE, CMR has deployed two state-of –the-art scanning lidar systems, which record wind speeds up to an altitude of 1000 m. In addition, a passive microwave radiometer provides vertical profiles of temperature and humidity up to an altitude of 1000 m. These measurements are combined with the lidar measurements to obtain information on stability conditions within the lower 200 m of the atmosphere. This is the first time that such measurements are performed continuously nearby an offshore wind farm.

Ultra sonic anemometers at FINO1 perform high frequency measurements of the 3D wind vector at 40, 60 and 80 m. These data can be used to investigate small scale turbulence at the FINO1 site, which impacts turbine performance and rotor blade fatigue. In order to increase the vertical resolution of these high-frequency wind measurements, NORCOWE has mounted two additional sonic anemometers at 15 and 20 masl. This also provides the opportunity to investigate air-sea interactions at FINO1.

To gain better understanding of the interactions between the ocean, the atmosphere and offshore structures (such as wind turbines), several oceanographic instrumentations were deployed between May – October 2015. The oceanographic research focus on how waves interact with the atmosphere in the presence of offshore wind farms. This aims to improve our understanding of wind farm wake characteristics in the presence of combined wind and wave effects. The influence of wind turbine structures to upper ocean processes such as currents and turbulence characteristics is investigate as well.