The 1.4GW Sofia offshore wind farm is being built by energy firm RWE and, once complete, will be one of the world's largest single offshore wind farms.
Expected to be operational in 2026, Sofia forms part of the Dogger Bank wind farm project that will boast a combined energy output of 4.8GW.
The Leonardo da Vinci vessel, built by Prysmian, is laying the first sections of high-voltage direct current export cables, which will be used to transport green electricity from the wind farm back to the UK coast.
Prysmian's 170m-long vessel will operate out of the port of Middlesbrough and will lay two 130km sections of cable in parallel.
It will start its cable-laying work just off the Teesside coast, and one end of each of the two sections of subsea cable will be pulled underwater from the vessel through cable ducts that were installed earlier this year.
The cable will pass below the beach, sand dunes and road before emerging at the landfall construction compound. The cutting-edge vessel will then move away from the coast, laying the full length of cable along its route towards the offshore wind farm.
The work marks a significant milestone for the project, with Sofia representing more than £3bn of investment in the UK's energy infrastructure by RWE. The wind farm will help the UK meet its net zero targets and will be capable of generating enough clean electricity equivalent to meeting the needs of over 1.2 million typical UK homes.
Sven Utermöhlen, CEO RWE Offshore Wind, said: "Sofia is RWE's largest renewable construction project to date, and its furthest from shore. The project is setting new standards in terms of addressing innovation, sustainability and engineering challenges.
"The laying of the first section of export cable represents the culmination of 13 years of planning, preparation and diligence, as well as a huge amount of support from suppliers and stakeholders alike."
Sofia is located on Dogger Bank, 195km from the nearest point on the UK's north-east coast, and will have a single offshore converter platform, with the electricity generated transported to landfall 220km away in Redcar, Teesside.
Last year, a study found that the UK would need to triple its current rate of wind turbine installation in order to meet renewable energy targets.
The wind farm will use 100 Siemens Gamesa 14MW offshore wind turbines, some of the most advanced available. Forty-four of the project's 100 turbines will be equipped with recyclable blades.
Installation of two remaining 90km sections of marine export cable is planned for 2024 and will have a total length of 440km.
