ScottishPower Renewables’ first-ever High Voltage Direct Current (HVDC) offshore converter station has been successfully installed at East Anglia THREE. 

Heavier than the Eiffel Tower and taller than the Statue of Liberty, the 10,700 tonnes, seven-storey structure was lifted and safely secured at the windfarm last week, around 69km off the Suffolk coast.

At around 70 metres long, 34 metres wide and 48 metres high, the module is the biggest ever constructed across the whole of the Iberdrola Group.

The HVDC station will convert electricity from high-voltage alternating current (AC) to direct current from the windfarm’s 95 turbines.

The £4 billion East Anglia THREE project is a joint project between Iberdrola and Masdar, who took a 50% stake in the windfarm in July 2025 as part of a wider strategic partnership. The Masdar–Iberdrola partnership is one of the largest bilateral alliances in the global clean energy sector.

The installation process was completed by the biggest crane vessel in the world, the Heerema Marine Contractors’ SSCV Sleipnir, which already installed the offshore jacket foundations for the project earlier this summer.

Fabrication of the module was completed in Mangalia, Romania in mid-2024, after which it sailed over 3,800 nautical miles to Aker Solutions’ fabrication yard in Stord, Norway, for completion.

At 1.4 GW, East Anglia THREE will be the biggest-ever windfarm across the whole of the Iberdrola group and among the largest in the world when it comes into operation at the end of 2026 – producing enough clean energy to power the equivalent of more than 1 million homes.

Charlie Jordan, CEO ScottishPower Renewables, said: “Installing our first ever offshore HVDC converter station is testament to the hard work of our teams and suppliers to deliver such a complex feat of engineering. This is a significant milestone for our East Anglia THREE project as we progress towards completion at the end of 2026.”

Darren Davidson, Vice President of Siemens Energy UK&I, said: “This is a fantastic landmark moment, East Anglia THREE is our first HVDC grid access project to be delivered in the UK. HVDC enables efficient long-distance power transmission with reduced losses, supporting the UK’s grid stability. Together, we’re delivering clean energy from the North Sea to power people’s homes.”

EVP Sturla Magnus in Aker Solutions, said: “East Anglia THREE marks Aker Solutions' second HVDC delivery this year and is a clear example of our ability to execute large and complex energy projects. Special thanks to consortium partner Siemens Energy, heavy-lift partner Heerema Marine Contractors and to client Scottish Power Renewables for their trust and cooperation.”

Michel Hendriks, COO Heerema Marine Contractors said: "We are proud to have installed the East Anglia THREE OCS topside on behalf of Aker Solutions. Completing this project in the shoulder seasons is a testament to our crew’s dedication and Sleipnir’s incredible capabilities. Working as one team with Scottish Power Renewables and Aker Solutions, we delivered a textbook example of successful offshore Installation.”