Operational Noise

Measurement of the operational underwater noise immission of wind turbines of the alpha ventus offshore wind farm

Project leader:
FH Flensburg - University of Applied Sciences, Flensburg

Duration of the project:
01/2008 – 12/2011

Contract number of the project:

Main research questions

  • How loud are single 5 MW offshore wind energy converters in the water?
  • What amount of underwater noise does the alpha ventus wind farm produce?
  • How do weather and tide conditions influence underwater noise production and propagation?
  • What is the shape of the transfer-function between tower vibration and underwater noise?

Goal of this research project is the measurement of the operational underwater sound immission of different types of 5 MW offshore wind energy converters (OWEC) under varying boundary conditions. Background of the project is the question of the exposure of marine animals to noise, especially marine mammals, in the vicinity of offshore wind farms.

The noise production of OWEC and the underwater sound propagation are influenced more or less by many parameters (boundary conditions), such as wind velocity, wind direction, sea state, water height, water flow profiles, water temperature, water temperature profiles, salinity, etc. The following problems will be investigated:

  • Measurement of the underwater noise production of different types of OWEC under various boundary conditions
  • Determination of the transfer function between tower vibration (structure-borne sound) and emitted underwater noise for different types of OWEC
  • Influence of different boundary conditions on sound propagation
  • Measurement of the total underwater noise immission of the alpha ventus wind farm at all possible boundary conditions.

To this end a total of 5 hydrophones will be positioned about 3 meters above the sea bed near 2 OWEC and near the research platform FINO1, which is located at a distance of 400 m from the wind farm. In addition acceleration sensors will be mounted at the underwater and over-water sections of the OWEC towers. Measuring computers that are installed in both OWEC and on FINO1 will digitize the signals of the acceleration sensors and hydrophones and will transmit the data to a file server onshore. The measuring system can be remote controlled from onshore so that measurements can be performed in all weather conditions.

Final report

You can find the final report (only available in German) here.


Oral presentations, Conferences, symposia, workshops

Benesch, M., van Radecke, H. (2012): RAVE Underwater Operational Noise Measurements in the Offshore Wind Park Alpha Ventus – Project Description and Final Results.
DEWEK 2012, 11th German Wind Energy Conference, Bremen, November 2012.

van Radecke, H., Benesch, M. (2012): Operational underwater noise at alpha ventus. Project: RAVE – Operational noise.
RAVE International Conference 2012, Bremerhaven, May 8-10, 2012. Download PDF

Benesch, M., van Radecke, H. (2010): Underwater Operational Noise Measurements in the Offshore Wind Park alpha ventus, Project Description and First Results.
DEWEK 2010, 10th German Wind Energy Conference, Bremen, November 2010.