Vattenfall, Metsähallitus Award Geophysical Survey Contracts for Finnish Offshore Wind Farm

July 11, 2024, by Adnan Memija

Vattenfall and Metsähallitus have awarded GEOxyz and Arctia contracts to provide geophysical surveys for the Korsnäs offshore wind farm in Finland.

Vattenfall became a Metsähallitus project partner for the Korsnäs offshore wind farm in December 2022.

The surveys involve mapping a 280 square-kilometre offshore wind farm area and two alternative corridors for the export cables to connect to the power grid.

For the survey work, the companies will use Arctia’s Kaiku and Keila 1 vessels equipped with sensors to map the seabed morphology in high detail using multibeam echo sounders and shallow geology using sub-bottom profilers.

A side-scan sonar and magnetometer are planned to be towed to identify natural boulders and man-made objects such as wrecks and classify the seabed in combination with sediment sampling.

Later, GEOxyz will mobilise the 55-metre Geo Ocean VI to conduct a 2D Ultra-High-Resolution-Seismic (UHRS) survey to obtain insight into the sub-seabed geology up to 100 metres below the seabed.

The water depths in the research area range from 1 metre to 50 metres, and the terrain is characterized by steep slopes and expected high variability in geological characteristics.

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GEOxyz and Arctia included bathymetric LiDAR operations to survey the ultra-shallow parts from the air to map potentially dangerous shallow zones before marine operations, said GEOxyz.

“This contract represents a critical milestone, marking a significant step forward in our efforts to develop Finland’s first major offshore wind farm. By thoroughly understanding the seabed conditions, we can move a crucial step closer to realizing the project,” said Anders Thomsen, Technical Project Manager at Vattenfall.

The Korsnäs offshore wind farm, with a planned maximum capacity of 2.5 GW and a potential annual production of 7 TWh, will be located at Korsnäs, on the west coast of the country, according to Metsähallitus.

The project is expected to be operational in the 2030s.