Partners to demonstrate performance

The project that W3GM are promoting is the HydroNAS https://www.w3gmarine.com/hydronas.html a product developed to reduce underwater noise that occurs during the installation of piles in water. The noise that is generated is sufficient to cause permanent damage to the hearing of various creatures that live in the sea and in particular harbour porpoises, dolphins, whales, seals and other cetaceans. The noise can be fatal for the cetaceans.

The noise that is attenuated by the HydroNAS is the ‘near field’ noise generated by the pile in the water column (as against ‘far field’ noise which is generated through the seabed during pile driving operations). The attenuation is between 25dB Sound Equivalent Level (SEL) and 50dB SEL or 35 – 55dB peak noise depending on whether one or two barriers are used. This has been demonstrated through the following:

• Nearshore Trial at the Tay Estuary (Dundee), supported by two Offshore Windfarm Developers and a SMART grant
• Offshore trial on the Kentish Flats Windfarm monopile installation
• Optimisation trials at the National Physical Laboratory Wraysbury Reservoir Facility
• Analysis by world renowned Southampton University (ISVR)
• Analysis and endorsement by world leading expert, Dr Michael Bellmann

The HydroNAS uses drop-stitch material to create a complete air wall around the pile from the seabed to the surface (one such barrier gives 25 dB SEL and 35dB peak noise reduction, two such air walls will double the performance). The system attenuates the noise in the 80 – 1,000 Hz range which is the high risk range of frequencies for Cetaceans.

No other competing nearfield system can achieve anything like this level of underwater noise reduction and in the most harmful range. Because of the material used, the system can be layered to reduce noise yet further. W3G now need to apply the system to industrialised offshore piling operations and we are seeking to collaborate with partners.

Because of the huge energy required to hammer monopiles into the seabed it is particularly suited to that application.

Target market are, ultimately, the Offshore Wind Developer (which will have to adhere to noise limits - or potentially have work suspended, through Consent/Licence condition) and their T&I contractor which usually provides the noise mitigation system (NMS).

Monopiles are widely used worldwide for fixed bottom foundations and this is expected to continue. The future global market is enormous. Most countries deploying offshore wind at scale are developed or already have underwater noise limits for developers to adhere to during construction works. The US has mandated limits for underwater noise.

Monopiles continue to grow in size (one Developer has advised us that they investigating 15m diameter Monopiles) and in an increasing water depth. As hammer energy increases so too does the associated underwater noise.

Route to market is via a T&I contractor(s), with the support of the Developer. W3G strongly believe that once a credible efficient deployment scheme has been developed and tested for the HydroNAS, then the HydroNAS will become the 'go to' system. It has many advantages over the alternative near field noise mitigation systems, including far superior noise reduction (and can be layered), lightweight, of low cost and could be integrated into a 'gripper' arm.