The first phase of a six-month offshore site investigation for innogy’s Sofia offshore windfarm got underway this week as the multi-purpose vessel Fugro Pioneer left the Port of Sunderland to survey the project’s 220-km 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 windfarm site on Dogger Bank in the North Sea.
The survey will provide the project’s consent and engineering teams with data about the seabed and marine conditions prior to construction.
At 1.4 GW, Sofia is the largest project in innogy’s development portfolio and one of the world’s biggest offshore windfarms.
innogy Sofia senior project manager Damien Fensome said Fugro Pioneer will focus on geophysical surveys and will be at sea for up to a month, with members of both the Sofia and Fugro teams on board. A local guard vessel will be chartered to support the campaign.
“This initial suite of surveys will cover a variable corridor of around 175 m wide, and will include environmental grab samples, drop down video transects, sub-bottom seismic profiling, side-scan sonar, bathymetry and magnetometer surveys,” he said.
The export cable route geotechnical surveys that also form part of this first phase of the site investigation are due to start in March and will take up to a month to complete. These surveys will include cone penetration tests and vibrocores and will be carried out from another vessel, Despina.
“The information collected will be analysed to build up a comprehensive picture of the seafloor and sub seafloor conditions, informing the need for further surveys, the final cable route, the landfall location and the most appropriate cable installation methodologies,” Mr Fensome explained.
“Given that Sofia’s 600-km2 array site is 195 km from the coast of the northeast of England, and the export cable will be 220 km long, we believe this is the longest such cable route survey ever undertaken for an offshore windfarm.”
Further surveys are also planned to take place 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 2020.