Offshore construction

This page features the latest updates on Sofia's offshore construction progress and upcoming activity. It includes details of the main contractors that will ensure the successful delivery of the project's infrastructure offshore, from the array site on Dogger Bank to landfall in Teesside.

LOCATION OF OFFSHORE INFRASTRUCTURE

Offshore map with turbine locations

OFFSHORE CONSTRUCTION OVERVIEW

Following the completion of the landfall horizontal directional drill to install ducts in early 2023, offshore construction started in September 2023 with the first phase of the installation of Sofia's two 220 kilometres long export cables. The brand new vessel Leonardo da Vinci has carried out the work, in two phases.

Work on the Dogger Bank site started in 2024 with the installation of the first of the project's 100 extended monopile foundations, delivered by the vessel Aeolus. 2024 was a busy year with the installation of the export cables, foundations, 350 kilometres of array cables and, at the heart of the wind farm, the 13,000 tonne offshore converter platform and its 7000 tonne jacket foundation.

2025 has already seen its first major milestone, with the installation of the first of the 14MW turbines.

Soon we will be fitting turbines with recyclable blades. 

Looking across 2025, we expect to complete the foundation and array cable installations, commission and energise our onshore and offshore platforms, and generate first power.

Construction is anticipated be completed by the end of 2026.

WHAT'S HAPPENING OFFSHORE

The offshore site is a busy space at the moment with a range of activities happening concurrently. 

The Van Oord vessel Aeolus continues to install the foundation pieces, with the 100th due in July. Meanwhile the Calypso, also under Van Oord's direction, is installing array cables. The Calypso will leave the field in June, to be replaced by the Boka Ocean.

The Wind Peak, by Cadeler, has begun installing wind turbines, which we estimate will take around 12 months.

Much work is being done on the offshore converter platform in readiness for energisation, which will happen in Q3 2025.

You can see the latest images of this work in our image gallery.

OFFSHORE CONSTRUCTION TIMETABLE

OFFSHORE-RELATED DOCUMENTS

Sofia submits documents related to the offshore activity to the Marine Management Organisation to approve and then store and make publicly available. To view the documents related to Sofia you can access the MMO Public Register and search under DCO/2016/00021 and DCO/2016/00019.

One of the key offshore construction documents is the Project Environmental Management and Monitoring Plan.  It sets out how environmental impacts will be managed during Sofia’s offshore construction and operation, covering the environmental frameworks and procedures that will be followed by all contractors and sub-contractors in relation to marine pollution, chemicals, waste and disposal.

For Fisheries-specific documents please visit the For Mariners section of the website.

OFFSHORE CONTRACTORS

CONTRACTOR DESCRIPTION WEBSITE

Siemens Gamesa Renewable Energy (SGRE) will manufacture, fabricate and install Sofia's 100 wind turbines.

Siemens Gamesa Renewable Energy

GE’s Grid Solutions will be responsible for the engineering, procurement, construction and installation of the offshore (and onshore) HVDC converter stations capable of transmitting 1,400 megawatts of power at 320 kilovolts.

GE's Grid Solutions

Working in a consortium with GE's Grid Solutions, Sembcorp Marine will build and install the offshore platform and jacket foundation.

Sembcorp Marine

Van Oord will deliver the project's 100 foundations and 350 kilometres of array cables.

Van Oord

Prysmian Group will design, supply, install and commission Sofia's HVDC export link including 440 kilometres of offshore export cables and installation work.

 

Prysmian Group

 

Heerema Marine Contractors will transport and install Sofia's offshore converter platform using Sleipnir, the world's largest sustainable semi-submersible crane vessel.

 

Heerema Marine Contractors

Cadeler has commissioned two brand new X-class vessels to transport and install the project's 100 turbines. They will be completed in late 2024 and early 2025 respectively.

Cadeler

Hellenic Cables will design, engineer, manufacture, test and supply Sofia's approximately 360 km of 66 kV XLPE-insulated inter-array cables and associated accessories. 

 

Hellenic Cables

EEW will deliver Sofia's 100 extended monopile foundations under a contract with Van Oord.

EEW

Port of Blyth will be the location of the offshore construction base for Sofia's team for the duration of offshore works.

Port of Blyth

Specialist Marine Consultants will deliver offshore resources and services for the project's offshore construction phase.

Specialist Marine Consultants (SMC) 

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