Germany’s Innogy has kicked off the first phase of its 1.4GW Sofia offshore wind project —formerly known as Dogger Bank Teesside B — with survey of the project site and potential cable-export routes.

Dutch contractor Fugro will provide geophysical and geotechnical services at the project site in the middle of the North Sea, 195km from the coast of northeast England, and along the cable-route corridor — believed to be one of the longest cable-route surveys ever performed for an offshore wind farm.

At 1.4GW, Sofia is the largest project in Innogy’s development portfolio and one of the world’s biggest offshore wind farms. Originally one of four Dogger Bank area developments granted consent orders in August 2015, Sofia won a Contract for Difference (CfD) award after bidding at a world-record low strike price of £39.65/MWh ($48.8/MWh) in the UK’s third CfD auction last year.

Power from Sofia, which sprawls over an area of almost 600 square kilometres of the Dogger Bank area in the North Sea, will feed into the national grid at an existing substation in Lackenby, Teesside.

The Fugro Pioneer vessel left the port of Sunderland earlier this month to start a six-month offshore site investigation and survey work to better understand the organisms and archaeology that might line the route and to enable detailed design for the proposed wind farm.

Fugro will also use two of its geotechnical vessels, the Fugro Frontier and Fugro Seeker, to provide drilling, seabed sampling and in-situ testing. Once the geo-data is acquired, Fugro will produce a ground model for Innogy.

“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 Innogy’s Sofia senior project manager Damien Fensome.

Further surveys are also planned to take place during the spring and summer, along the export cable route, as well as at the project site and closer to shore. The full site investigation work is due to be completed by August 2020.

Sofia was taken over 100% by Innogy in August 2017. The developer was last year cleared to use up-to-20MW turbines at the project following approval by the British authorities of plans to expand the development’s maximum installed capacity by 200MW to 1.4GW.