Construction of offshore wind farm ‘EnBW He Dreiht’: EnBW and Heerema showcase major noise reduction with innovative noise mitigation system

Leiden/Hamburg - EnBW and Heerema Marine Contractors have jointly achieved a significant milestone in environmental stewardship at EnBW’s He Dreiht offshore wind farm. Testing and real-world applications have demonstrated that the innovative noise mitigation system T-NMS-10000, constructed in collaboration with IQIP, in combination with a double big bubble curtain and IQIP's PULSE system reduces underwater noise up to 24 decibels (dB).

The T-NMS-10000 is a giant subsea noise barrier for monopiles, effectively containing internal noise emissions. Its massive steel structure comprises an inner tube (approximately 12 meters in diameter; suitable for 10m diameter monopile) and an outer tube (roughly 13 meters in diameter), separated by rubber blocks. Air compressors expel the water column between these tubes, creating an air barrier across the entire water depth. The T-NMS-10000 contributes a big part in the noise mitigation spread by reducing noise already up to 15 dB as measured by ITAP.

In response to stringent environmental regulations that are applicable in the German Bight, a maximum of 160 dB at 750 meters from the source, EnBW committed very early in the He Dreiht project design to the development of this latest generation NMS, essentially an upscaling of previous systems complemented with the truss frame template structure, enabling its deployment with floating installation vessels. Heerema accelerated and completed its development by additional research and engineering efforts. The need to reduce underwater noise pollution aligns with Germany’s commitment to marine conservation.

Stefanie Höper, Project Manager at EnBW: “The development of the free-standing T-NMS-10000 for application with floating installation vessels was initiated in 2022 by EnBW considering the application of an NMS fundamental to the installation of its 9.2 m diameter monopiles in the He Dreiht project within applicable noise limits. By pioneering the T-NMS-10000, Heerema, IQIP and EnBW not only meet regulatory requirements but also contribute to a sustainable future and set an example for sustainable marine construction.

After Heerema had been contracted for the installation, the T-NMS-10000 was further developed and built by Heerema and IQIP. Erik Bögels, Senior Project Manager at Heerema: “Having been involved in the development of the T-NMS-10000 for the past two years, we are thrilled to see it in action at the He Dreiht offshore wind farm installation. We have estimated the reduction performance of this tool extensively, so it's great to see that the T-NMS-10000 lives up to its expectations. This new tool not only significantly reduces the noise levels generated during pile driving, but also sets a new standard for sustainable marine construction practices.

About EnBW He Dreiht
'He Dreiht' will be Germany's largest offshore wind farm with 960 Megawatt and is scheduled to enter operation at the end of 2025. The sem-submersible crane vessel Thialf is progressing on the installation of the 64 monopiles and transition pieces in the next weeks. The unique thing about this project is that He Dreiht will be built without state funding. Around 2.4 billion euros are being invested in it. EnBW's offshore office in Hamburg is coordinating the major project.

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