WavEC Offshore Renewables has published findings following the first offshore surveys at the Technological Free Zone offshore of Viana do Castelo, Portugal, a site that will host floating offshore wind demonstration projects.
The study was supported by oceanographic surveys carried out in March and October of 2023, collecting acoustic data and physical samples of the seabed.
The report, which presents the findings from the first phase of a two-part study commissioned by WavEC and created by Instituto Hidrográfico, provides a detailed analysis of the seabed geomorphology, sedimentary layer composition, and overall seafloor characteristics. This will play a crucial role in the engineering, design, and deployment of floating wind projects, ensuring that mooring systems and foundation designs are optimised for seabed conditions, according to WavEC.
According to the report, the Technological Free Zone (Zona Livre Tecnológica; ZLT) has a stable seabed which is predominantly smooth with a gentle 0.34° slope, except for a localised rocky outcrop and small geological depressions. The seabed has a consistent sedimentary cover, ranging from fine silt to very coarse sand. Three distinct sedimentary layers were identified, with the top layer averaging ~13 metres in thickness.
The Viana do Castelo Technological Free Zone covers an area of 7.63 square kilometres and is adjacent to the 25 MW Windfloat Atlantic floating wind farm.
The Portuguese government announced the establishment of the Technological Free Zone in 2021 and issued an order for the delimitation of the site in October 2023 .
In December 2024, the government signed the rules of procedure for the Zone.
The purpose of the free zone is to provide a pre-consented area with a grid connection where renewable energy technology can be more easily deployed and tested without incurring all the normal regulatory processes.
Projects developed within the ZLT will be exempt from paying grid access tariffs and other charges related to grid contributions. However, they may be subject to a fee established by the Portuguese Energy Regulatory Authority (ERSE) to partially cover the grid operators’ investment and operation of the connection infrastructure necessary for the operation of the zone.