A major milestone has been reached in WILLOW’s underwater acoustic monitoring activities with the successful recovery of the hydrophone deployed at the Norther Offshore Wind Farm in the North Sea.
The recovery campaign was carried out with the support of VLIZ – Flanders Marine Institute and the research vessel Simon Stevin, which deployed several monitoring systems around the wind farm in October 2025. As part of this initiative, TSI | Técnicas y Servicios de Ingeniería integrated its own hydrophone into the campaign to collect acoustic data from a real offshore wind environment.
Over more than five months on the seabed, the hydrophone continuously recorded the underwater soundscape, capturing not only the acoustic signature of offshore wind turbines, but also vessel traffic, sea state variations, currents and other environmental noise sources. The resulting dataset provides valuable information for understanding underwater noise dynamics in offshore renewable energy installations.
The recovery operation marks an important achievement for WILLOW, where TSI leads activities related to underwater acoustic monitoring. It also offered a practical demonstration of the challenges associated with long-term offshore monitoring campaigns, including the significant biofouling that accumulated on the instrument during its deployment and effectively transformed it into a temporary habitat for marine organisms.
Following the recovery, TSI has begun processing and cataloguing an extensive dataset comprising more than 3.5 TB of acoustic recordings distributed across over 25,000 files. This unique collection of data will support ongoing research into offshore soundscapes and contribute to a better understanding of the interactions between renewable energy infrastructure and the marine environment.
The work represents another step forward in WILLOW’s efforts to develop advanced monitoring solutions that support more sustainable and environmentally responsible offshore wind operations. Through the collaboration of research organisations, industry partners and marine experts, the project continues to generate valuable knowledge for the future of offshore renewable energy.
