TenneT Seeks Contractors for Hollandse Kust Zuid, Noord Offshore Platforms

TenneT has launched a qualification process for candidates interested in tendering for the delivery of offshore platforms that will connect wind farms at Hollandse Kust Zuid and Hollandse Kust Noord offshore areas to the Dutch grid on the mainland. 

Image source: TenneT

The scope of the intended contracts includes design, engineering, production, delivery, transport and installation of topsides and jackets.

Topsides will be 45m long, 21m wide, and 30m tall, and will have a weight of approx. 3,000 tonnes. The weight of the jackets is approx. 1,650 tonnes.

The Dutch offshore transmission system developer and operator will build five identical transformer stations with a total capacity of 3,500MW to transport wind energy to the Dutch onshore grid via HVAC subsea cables. The platforms within one area will be connected by means of a 66kV cable. The platforms will carry high-voltage switching and transformation equipment 220kV as well as auxiliary facilities. Intake power from the wind farms will be 66kV, export power from the platform will be 220kV.

The platforms were developed jointly with the wind farm developers, in an extensive consultation process based on an exchange of knowledge and experience. The standardization of the platforms will result in a substantial reduction of the costs of development, construction and maintenance, TenneT said last year as it presented the design for the offshore platforms.

The offshore grid will be rolled out in parallel with the development of the wind farms to ensure that the available capacity and the demand are optimally matched.

In February, TenneT awarded HSM Offshore with a contract for the construction of the Borssele Alpha transformer station, and also named HSM Offshore as the intended partner for the next offshore wind energy project, Borssele Beta.