Vattenfall completes all Nordlicht I foundations

Vattenfall has completed the installation of all 68 foundations for its Nordlicht I offshore wind farm in the German North Sea, bringing the project through one of its largest offshore construction phases ahead of schedule. The last monopile was installed at the end of September, and all remaining transition pieces have now been fitted. The 980MW development is located about 85 kilometres north of Borkum and is planned to become Germany’s largest individual offshore wind farm.

A monopile transfers the turbine’s weight and the forces from wind and waves into the seabed, while the transition piece creates the accurately aligned connection to the tower above. Its elevation and orientation also have to suit the access and service equipment carried by the foundation. Installing the transition pieces after the last monopile therefore completes a distinct mechanical interface needed for the turbine erection campaign, although the remaining generating and electrical systems are still being manufactured and installed.

The first Nordlicht I monopile was installed in July, with components fabricated at separate specialist facilities before offshore assembly. EEW Special Pipe Constructions manufactured the monopiles, CS WIND Offshore produced the transition pieces, and DEME transported and installed both types of structure. Coordinating those production and transport schedules kept the offshore foundation campaign supplied with the correct components in installation order. With the last transition pieces in place, the fabrication and heavy installation work has delivered all 68 structural interfaces for the turbine programme.

Monopiles of this size require specialised heavy-lift vessels and carefully sequenced deliveries. Earlier construction details put the largest structures at about 80 metres long and as much as 1,290 tonnes, with lifting and placement undertaken at designated seabed locations. Once the foundations are fixed in position, later contractors can work from established turbine locations instead of managing concurrent heavy foundation lifts. The collection circuits, export connection, and protection equipment must then be installed and tested as separate electrical work packages before power export can begin.

With all foundation positions prepared, component production elsewhere in the Nordlicht supply chain is continuing. TKF is manufacturing cables, and Vestas has begun turbine tower production, with initial tower sections already delivered to Esbjerg. Production of blades and nacelles is expected to start in the coming months. These activities overlap in time, allowing the offshore programme to move from foundation construction into the next equipment and installation phases rather than waiting for every component to be manufactured before the following campaign can begin.

The turbine towers will carry Vestas V236-15MW machines at Nordlicht I’s 68 positions. Their output must eventually be gathered by inter-array cables and transferred through offshore electrical infrastructure towards Germany’s high-voltage grid. Electrical protection and switching will need to coordinate generation across the array and isolate equipment when faults occur. The completed foundations establish the mechanical positions for that equipment, while cable manufacture, turbine assembly, installation, and commissioning remain on the delivery programme.

Nordlicht I is the larger of two adjacent projects. Nordlicht II is designed to add approximately 630MW using a further 44 turbines, bringing the combined Nordlicht cluster to more than 1.6GW. Vattenfall expects first electricity from the cluster during 2028, with full commissioning scheduled in 2029. Its project programme gives Nordlicht I a commercial operation target during 2028 and the neighbouring project a later target during 2029, reflecting the separate construction and commissioning sequences.

Vattenfall estimates annual output from the completed Nordlicht cluster at about six terawatt-hours, equivalent to the electricity consumption of roughly 1.7 million German households. That forecast covers both offshore projects after commissioning. Electricity production depends on installing and energising the turbines and grid connection, so the newly completed foundation package is a construction milestone rather than an operating generation asset.

Construction has also included measures intended to limit environmental impacts. Parts of the turbine towers are being produced with lower-emission steel, with Vattenfall reporting a reduction of around 16% in the towers’ associated carbon footprint against conventional production. Offshore activity has incorporated measures to reduce disturbance during foundation installation, while radar, camera, and acoustic monitoring are gathering information on birds and marine mammals in and around the development area.

Environmental monitoring continues as the site moves into the next construction campaigns. Radar and cameras record bird activity, while acoustic equipment contributes information about marine mammals in and around the offshore works. The observations provide a record of conditions during installation and will help assess environmental measures as the completed structures, turbines, and operating wind farm change activity at the site. The monitoring programme runs alongside fabrication and offshore installation rather than replacing the project’s normal engineering checks.

Foundation installation is now complete at Nordlicht I, with the last transition pieces fitted after the September monopile milestone. TKF continues manufacturing cables and Vestas is delivering tower sections to Esbjerg ahead of blade and nacelle production. These work packages feed into turbine installation and electrical integration, while Nordlicht II advances on its separate programme. Vattenfall continues to target the cluster’s first electricity in 2028 and full commissioning in 2029.