German electric utility major RWE has chosen French company Chantiers de l’Atlantique’s offshore energy business unit to design, manufacture, install and commission two electrical offshore substations for the 1.6GW Nordseecluster in the German North Sea.

The Nordseecluster will comprise four wind farms, which will be built in two phases.

The first phase, Nordseecluster A, will include two wind farms with a combined capacity of 660MW.

The substations will collect and transmit the power generated from the wind turbines using high-voltage submarine cables. They will also remotely control and monitor the wind farms’ operations.

The first substation will have a 435MW power rating. It will weigh 2,500 tonnes (t) and be placed on an 1,800t jacket-type foundation.

The second substation, weighing 1,800t, will have a power rating of 225MW. It will be mounted on an 800t transition piece and placed on a 2,000t monopile foundation.

Design work has already begun with advanced studies. Purchasing activities will continue until RWE takes the final investment decision.

The permit application process is expected to begin in 2024. The substations will be installed and commissioned in 2026.

RWE Nordseecluster managing director Sven Schulemann stated: “With this agreement, we have passed the next milestone on the way to completing the first two offshore wind farms of our Nordseecluster. When they become operational in 2027, we will be making a further contribution towards supporting the decarbonisation drive in our home market.

“After the successful delivery of the Arkona offshore substation in 2018, we are looking forward to working with Atlantique Offshore Energy again.”

Phase two, Nordseecluster B, will include two additional wind farms with 900MW of capacity and is expected to come online in 2029.

Nordseecluster A and B will power 1.6 million German households annually.

In May 2023, RWE took sole ownership of Nordseecluster by buying out the stake of co-owner Northland Power.