Seaway7 is preparing to begin inter-array cable installation at the 2.9 GW Hornsea 3 offshore wind farm off Norfolk, UK. Cable laying vessel Seaway Phoenix is due on site October 19, according to an Ørsted project notice. The wind farm sits 120 kilometers offshore and is expected to be completed around the end of 2027.
The 197 turbine Hornsea 3 Offshore Wind Farm is being delivered by Ørsted with Apollo managed funds, which hold a 50 percent stake after a DKK 39 billion ($6.5 billion) divestment completed in December 2025. Once operating, the project is expected to power more than 3.3 million UK homes, according to Ørsted. Moreover, the developer projected up to 5,000 construction jobs and up to 1,200 permanent roles when it took its final investment decision.
The same pressure on subsea cable and converter capacity is shaping interconnectors far from the North Sea. In the Mediterranean, the Tunisia-Italy ELMED power link, which secured a US$268 million World Bank loan in 2023, saw Terna and STEG issue Prysmian a notice to proceed in June 2026 for a €460 million ($530 million) subsea cable contract. Hitachi Energy received a €770 million converter station award two days later, and both suppliers also work on Hornsea 3, where Prysmian supplies inter-array cables and Hitachi Energy supplies the HVDC converter systems. Wael Chouchane, Tunisia’s Secretary of State for Energy Transition, said earlier this year that ELMED could now finish in 2030 or 2031 because strong global demand for electrical equipment has strained supply chains.
Seaway7 Mobilizes Three Vessels for Hornsea 3 Offshore Wind Farm Cable Installation
Seaway7 is expected to start installing inter-array cables at the Hornsea 3 Offshore Wind Farm in the coming days. Seaway Phoenix is loading cable in Eemshaven, the Netherlands, and is planned to reach the site on October 19.
Meanwhile, Seaway Moxie is mobilizing in Eemshaven to support the campaign and is due to sail for the Hornsea 3 Offshore Wind Farm on October 15. Grand Canyon 3 starts mobilizing from Blyth, UK, on October 17 for pre trench survey and trenching, with work at the site scheduled for October 20.
Ørsted awarded Seaway7 the transport and installation contract in 2024. The scope covers 192 inter-array cables rated at 66 kV, with a combined length of roughly 500 kilometers, comparable to the straight line distance between London and Edinburgh.
Additionally, Seaway7 has contracted Helix Robotics Solutions to bury all 192 cables. That campaign is expected to last more than 300 days and was originally scheduled to begin in the third quarter of 2026.
Hellenic Cables and Prysmian Group each supply about half of the array cable requirement, while JDR Cable Systems handles testing and termination. As a result, five companies share the work across cable manufacture, installation, burial and testing.
Hornsea 3 Offshore Wind Farm Advances With Both Offshore Converter Stations in Place
The second offshore converter station at the Hornsea 3 Offshore Wind Farm was installed in September 2026, completing a pair that began with the first unit earlier this year. Each station stands about 70 meters above sea level, which Ørsted compares to 1.2 times the height of the Leaning Tower of Pisa, according to the project update.
Aibel and Hitachi Energy supplied the stations, and Heerema Marine Contractors reported that its Sleipnir heavy lift vessel installed the first one ahead of schedule. Hornsea 3 is also Ørsted’s first UK offshore wind farm to use HVDC transmission, a technology suited to the 120 kilometer distance to shore.
Offshore foundations are advancing in parallel. Installation of the 197 monopiles began in May 2026 with Cadeler’s Wind Ally vessel, and each foundation averages 1,670 metric tons and 90 meters in length, roughly the height of a 30 story building.
Furthermore, export transmission relies on two HVDC cables and an interlink cable with a combined length of about 350 kilometers, supplied by NKT. The first export cable was pulled onto land in the first quarter of 2026, and power will ultimately enter the national grid through an onshore converter station at Swardeston, near Norwich.
Apollo and Mubadala Back Hornsea 3 Offshore Wind Farm Finance
Apollo managed funds acquired 50 percent of the Hornsea 3 Offshore Wind Farm and agreed to fund half of the remaining construction costs. Ørsted keeps the other half and continues to lead construction and operations.
In addition, Mubadala Investment Company disclosed a $325 million investment alongside the Apollo led consortium in May 2026.
Revenue is anchored by a contract for difference awarded in July 2022 at an inflation indexed strike price of £37.35 per megawatt hour in 2012 prices. The contract runs for up to 15 years from commissioning, according to Ørsted.
The project was priced at about £8 billion when Ørsted took final investment decision in December 2023, according to industry reporting at the time. Ørsted already operates Hornsea 1 at 1.2 GW and Hornsea 2 at 1.3 GW from its hub in Grimsby, and the Hornsea zone will exceed 5 GW once Hornsea 3 comes online.
Project Overview
- Project Name: Hornsea 3 Offshore Wind Farm
- Developer and Operator: Ørsted
- Co-owner: Apollo managed funds (50 percent), with Mubadala Investment Company investing alongside the Apollo led consortium
- Location: North Sea, about 120 kilometers off the Norfolk coast, UK
- Capacity: 2.9 GW
- Turbines: 197 Siemens Gamesa SG 14-236 DD turbines, rated at 14 MW excluding power boost
- Foundations: 197 XXL monopiles, averaging 1,670 metric tons and 90 meters each
- Grid Connection: Two offshore HVDC converter stations, export cables and an interlink cable of about 350 kilometers combined, and an onshore converter station at Swardeston, Norfolk
- Inter-Array Cables: 192 cables rated at 66 kV, about 500 kilometers in total
- Project Value: About £8 billion at final investment decision (industry reporting); later coverage cites £8.5 billion
- Revenue Support: Contract for difference at £37.35 per MWh in 2012 prices, for up to 15 years from commissioning
- Construction Status: Both offshore converter stations installed; monopile installation under way since May 2026; inter-array cable installation due to begin in October 2026
- Target Completion: Around the end of 2027 (Ørsted)
- Jobs: Up to 5,000 during construction and up to 1,200 permanent (Ørsted)
- Homes Powered: More than 3.3 million UK homes (Ørsted)
Project Team
Owners and Developer
- Developer, Operator and 50 Percent Owner: Ørsted
- 50 Percent Owner: Apollo
- Co-investor: Mubadala Investment Company
Cable Installation and Supply
- Inter-Array Cable Transport and Installation: Seaway7
- Inter-Array Cable Supply: Hellenic Cables
- Inter-Array Cable Supply: Prysmian Group
- Array Cable Testing and Termination: JDR Cable Systems
- Export Cable Supply: NKT
- Cable Burial: Helix Robotics Solutions (official website not verified, left unlinked)
Turbines, Foundations and Vessels
- Turbine Supplier: Siemens Gamesa
- Monopile Installation Vessel Operator: Cadeler
- Converter Station Installation: Heerema Marine Contractors
HVDC Transmission
- HVDC Converter Systems: Hitachi Energy
- Offshore Converter Platforms: Aibel
Related Project, ELMED Interconnector
- Transmission Operator, Italy: Terna
- Transmission Operator, Tunisia: STEG
- Financier, 2023 Loan: World Bank Group
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