Thor Export Cable

RWE’s Thor project information page lists “Installation of subsea cables” under the 2025 project milestones and notes that a consortium of Hellenic Cables and Jan De Nul manufactured and installed about 60 km of export cables along the 30 km route from the offshore wind farm to shore, plus inter‑array cables and onshore cables. Additional trade‑press reports show export cable pull‑in completed by mid‑2025. This confirms that export cable installation had started and was underway in 2025, though the precise start day is not stated.

By 5 July 2025, Jan De Nul had completed the offshore and onshore landfall operations to bring the two main Thor export cables from the North Sea to the Danish mainland. Using its cable-laying vessel Isaac Newton offshore and the Moonfish horizontal directional drilling (HDD) machine on land, the company drilled under the coastline and pulled the cables ashore with minimal impact on the coastal environment, leaving Thor’s export cables installed at the landfall and ready to be connected further inland.

On 5 July 2025, it was reported that Jan De Nul had completed the cable connection for Thor by finishing the offshore and onshore maneuvers required to lay and pull in the two main export cables from the Thor offshore wind farm site, located 22 km off Denmark’s North Sea coast, to the Danish mainland. With these works finished and the cables already onshore and in place, the export link is physically installed and positioned to eventually transmit up to 1,080 MW of renewable power to more than one million Danish homes once the project is fully commissioned.

In June 2025, Energinet announced it had completed the construction work related to connecting the 1,080 MW Thor offshore wind farm to the Danish national grid, indicating that the onshore export cable system between the landfall and the onshore grid connection point has been fully installed.

At the start of 2023, groundbreaking took place for the Thor project’s onshore high-voltage substation in Lemvig municipality, Denmark, marking the start of onshore construction for the grid connection that will receive Thor’s export cables. The substation is being built by Siemens Energy together with MT Højgaard Danmark, which are responsible for the civil engineering and construction works, and will be connected by onshore cables from the landfall to integrate Thor into the Danish national grid.

RWE’s 19 October 2023 press release on appointing Fugro for the Thor geophysical survey states that the UXO campaign for the Thor offshore wind farm will run until December 2023. Subsequent project updates show later offshore construction works starting on schedule in 2025, implying that the UXO survey campaign was completed by December 2023 as planned, although the exact day is not specified.

RWE’s 19 October 2023 press release states that RWE has commenced a geophysical survey off the Danish west coast for the Thor offshore wind farm, with up to three survey vessels deployed. This confirms the start of the detailed pre‑construction geophysical survey on that date.

The same 19 October 2023 RWE press release confirms that the detailed pre‑construction survey for Thor includes a search for unexploded ordnance (UXO) using multiple survey techniques. This indicates that the UXO survey component started together with the geophysical campaign on 19 October 2023.

On 25 April 2023, RWE awarded a turnkey contract to a consortium of Jan De Nul Group and Hellenic Cables for the export and inter-array cable systems for the Thor project, including two 275 kV HVAC export cables (each with 30 km offshore and 13 km onshore sections) and approximately 200 km of 66 kV inter-array cables. Hellenic Cables will design and manufacture the cables, while Jan De Nul will handle transportation, laying and burial along the 30 km route from the offshore wind farm in the Danish North Sea to shore, providing the main grid connection for Thor’s power export to Denmark’s onshore network.

On 25 April 2023, HSM Offshore Energy (part of the Smulders Group) announced it had been awarded the EPCIC — Engineering, Procurement, Construction, Installation and Commissioning — contract by RWE for the Thor Offshore High Voltage Substation (OHVS) that serves Denmark's largest offshore wind farm. HSM's scope covered both the jacket foundation and the topside of the 1 GW, 275 kV HVAC collector station, which aggregates power from 72 Siemens Gamesa SG 14-236 DD turbines and feeds it into the 58 km / 2-cable HVAC export cable system (delivered by Hellenic Cables and installed by Jan de Nul) landing at the Volder Mark onshore substation. Topside fabrication at HSM's Schiedam yard in the Netherlands was rolled out on 19 November 2024 and the completed OHVS sailed away to the Thor project site in July 2025, with offshore installation completed by 17 July 2025. This supplier selection event replaces the earlier year-precision placeholder (2023-01-01) that had been created from a keyfactsenergy.com summary citing only "early 2023"; the HSM press release provides the authoritative day-precision date.

On 9 January 2023, LS Cable & System was awarded a contract by Danish TSO Energinet to supply and deliver the onshore export cable section for the Thor offshore wind farm’s grid connection, comprising 21 sections with two 220 kV cable systems over approximately 28 kilometres, including supervision of civil works, cable pulling, joints, terminations, and final commissioning testing.

At the start of 2022, RWE signed a grid connection agreement with Danish transmission system operator Energinet for the Thor offshore wind project, securing the connection of Thor’s transmission system (including its export cables and substations) to the Danish national grid.

In 2022, Fugro completed a comprehensive geotechnical site investigation for RWE’s Thor offshore wind project off the Danish west coast, providing subsurface data to support the project’s detailed design and development.

On 12 March 2019, the Danish Energy Agency announced that the political parties behind the 29 June 2018 Energy Agreement had decided that, for the Thor offshore wind farm tender, the offshore substation and export cables—previously built and operated by Energinet and financed via tariffs—would instead be included in the scope of the wind farm tender, making the winning bidder responsible for these assets and their financing, while Energinet would remain responsible only for constructing and operating the onshore grid connection to the transmission grid, to be paid for by the tender winner subject to European Commission approval. This decision changed the regulatory allocation of responsibilities for Thor’s grid connection, directly affecting the Thor export cable system.