Hydraulic piledriving solutions specialist MENCK has been contracted by Seaway 7 to provide an MHU 3500S hydraulic hammer and spread for the installation of 140 monopile foundations for Vattenfall’s Hollandse Kust Zuid 1–4 (HKZ).
HKZ 1-4, a 1.5 GW project by Vattenfall, will be built between 18 and 36 km off the Dutch coast and will comprise 140 Siemens Gamesa 11 MW wind turbines. The wind farm was tendered in 2 phases: HKZ 1&2 and HKZ 3&4.
Vattenfall selected Seaway 7 as a partner for HKZ 1&2 in April 2019 and HKZ 3&4 in April 2020. The company will be responsible for the transport and installation of the 140 monopile foundations and 315 km of 66 kV inter array grid cables in water depths between 18 and 27 metres. The monopile foundations, to be produced by Sif Group, have a 7-metre outer diameter. This Summer, first mockup trials were performed for the foundation in Maasvlakte 2.
MENCK’s scope of work for Seaway 7 includes the manufacture, preparation and operation of one of its MHU 3500S hammers. This will have the largest piling adaption to date, the company said, and be capable of installing monopiles with a 7.5-m outer diameter.
The offshore operations phase is expected to take eight months and will be split into two installation campaigns.