TenneT starts tendering procedure for offshore cable systems

Dutch-German transmission system operator (TSO) TenneT has opened a qualification period for a tender for the supply and installation of HVAC cable systems in the N-3.7 and N-3.8 wind areas offshore Germany.

The scope of the intended contract includes design, engineering, production, delivery, project management, and installation of three ≥155 kV HVAC subsea cable systems in order to connect the offshore wind farms in the N-3.7 and N-3.8 zones to the associated high-voltage direct current (HVDC) offshore converter platform DolWin Kappa.

The tender is planned to be published between 17 October and 26 October.

Companies can be qualified to tender for cable supply, cable installation, or both.

For cable supply, the qualifications include experience in the design and manufacturing of AC or DC subsea cable with a rated voltage level ≥110 kV. For cable installation, one of the main conditions is experience with subsea power cable lay and burial.

TenneT recently installed the DolWin kappa offshore platform which will be the centerpiece of the 900 MW DolWin6 direct current link. The platform will bring offshore wind power from the German North Sea to land.

A few months ago, the transmission system operator invited all potential and interested market participants to express their interest in the planned market investigation for the DolWin6 HVAC Cable Systems that will connect the DolWin kappa platform with the wind farms in the N-3.7 and N-3.8 zones in Cluster 3, and to provide an overview of the current status of the planning documents.

The N-3.7 and N-3.8 sites are located some 30 to 40 kilometres north of the island of Borkum in the German North Sea. They were put out to tender for a combined capacity of 658 MW in February 2021.

In September 2021, Federal Network Agency (Bundesnetzagentur) selected RWE Renewables to develop a 225 MW wind farm in the N-3.7 zone, and EDF Renewables to develop a 433 MW project in the N-3.8 zone. Both developers had submitted zero-subsidy bids.

However, Nordsee Two GmbH, a subsidiary of Canada’s Northland Power and RWE Renewables, held the so-called step-in right for the N-3.8 zone which allowed this developer to match EDF Renewables’ winning bid in the auction and secure the lease for the 433 MW German Nordsee Two offshore wind project.

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