Sofia Offshore Site Investigations Kick Off

The first phase of the six-month offshore site investigation began this week as the multi-purpose vessel Fugro Pioneer left the Port of Sunderland to survey the project’s 220km export cable corridor.

As part of this phase, both geophysical and geotechnical surveys will be carried out along the route from just off Teesside, between Redcar and Markse-by-the-Sea, to the wind farm site on Dogger Bank in the North Sea.

This is expected to provide the project’s consent and engineering teams with key data about the seabed and marine conditions prior to construction.

According to innogy, Fugro Pioneer will focus on geophysical surveys and will be at sea for up to a month. A local guard vessel will be chartered to support the campaign.

“This initial suite of surveys will cover a variable corridor of around 175 metres wide, and will include environmental grab samples, drop down video transects, sub-bottom seismic profiling, side-scan sonar, bathymetry and magnetometer surveys,” said Sofia Senior Project Manager Damien Fensome.

The export cable route geotechnical surveys, also part of the first phase of investigations, will start in March and will take up to a month to complete. The work, which will comprise cone penetration tests and vibrocores, will be carried out from the vessel Despina.

“Given that Sofia’s 600km² array site is 195 kilometres from the coast of the North East of England, and the export cable will be 220 kilometres long, we believe this is the longest such cable route survey ever undertaken for an offshore wind farm,” Fensome said.

Further surveys are planned to take place during the spring and summer, along the export cable, as well as at the array site on Dogger Bank and nearer to shore. The full site investigation is due to be completed by August.

Sofia, the largest project in innogy’s development portfolio, will comprise up to 200 turbines located 165km off the North East coast on Dogger Bank.

The 1.4GW offshore wind farm is expected to enter the onshore construction phase in 2021, with commissioning scheduled for 2026.