Geotechnical surveys planned for Baltic Power

4C Offshore | Tom Russell
By: 06/07/2021 Baltic Power
Twelve specialised vessels are beginning the main phase of geotechnical surveys of the Baltic Power offshore wind farm and and cable connection route being developed by  PKN ORLEN and Northland Power. Completion of the tests is scheduled for later this year.

The results will provide a basis for the development of a detailed plan of locations of the foundations for the turbines and offshore substations and their connection to the onshore transmission infrastructure.

Baltic Power is finalising the key stage of investment preparations. The geotechnical tests will take from about 12 to about 16 weeks, depending on weather conditions. In this period, a total of 12 vessels will set sail from a number of ports, to operate both in the area of the offshore wind farm and along the route of the offshore part of the power connection. The farm area, spanning more than 130 sq. km, will be the place of operation of vessels drilling boreholes and sounding to depths of up to several dozen metres. Work of a similar scope, adjusted to the nature of the project, will be carried out along the more than 30 km long route of the cable connection to be used to export power to the onshore substation.

On the basis of the data collected during the drilling and sounding, and its subsequent analysis, designers will prepare documents such as the final plan showing location of the wind turbines, their support structures, and the farm site and power export cables route. The array seabed tests are being performed for Baltic Power by Gardline, while a Polish company MEWO is responsible for the measurements along the offshore connection route.

Under a contract signed with Baltic Power, DNV will carry out the certification of the final offshore wind farm project in accordance with the international IECRE standards.

The geotechnical tests on the farm site and along the cable connection route have been preceded by the start of UXO detection surveys, performed to search for any unexploded ordnance at sea. During the preliminary geophysical surveys carried out in 2019 for the purposes of an environmental report, dozens of objects that may pose a threat in the offshore construction phase were detected on the farm site. They included fragments of shipwrecks, rock formations, and remnants from World War II, such as a torpedo and a sea mine. A more extensive UXO survey will make it possible to verify the data already acquired and possibly identify other elements that may pose a risk on the offshore construction site.

​PKN ORLEN and Northland Power are jointly developing the site to host an array with a total capacity of up to 1.2 GW. Construction is expected to commence in 2023 with commercial operations expected in 2026. Last month Poland’s Energy Regulatory Office approved a Contract for Difference for the
Baltic Power offshore wind farm which was priced PLN 319.60 per MWh for up to 25 years, subject to some adjustments and final approval from Polish authorities and the European Commission.

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