Project record

Zeevonk phase 1 foundation installation

Fugro Synergy geotechnical vessel conducting seabed investigation work for the Zeevonk offshore wind project

Vattenfall; project-specific Zeevonk seabed-investigation image

Zeevonk has awarded DEME the foundation transport and installation package for the 1,062.6 MW wind component of its first permitted phase. The contract covers intermediate monopile transport, marshalling of primary and secondary steel, transport and installation of 69 monopile foundations, and placement of a filter layer for scour protection. The owner plans phase 1 for 2029, but has not published the marshalling port, fabrication split, installation vessel or offshore start date.

Project signal

Award in Netherlands

Current status DEME holds the transport and installation contract for 69 monopile foundations; offshore mobilisation has not been announced Source confidence Confirmed

Location

Netherlands / Europe

Segment

Offshore wind foundations

Status

DEME holds the transport and installation contract for 69 monopile foundations; offshore mobilisation has not been announced / Confirmed

Last checked

20 July 2026

Coverage

Related sectors

Offshore wind foundations is the primary work classification. Related sectors connect this record to adjacent marine delivery and market coverage.

Subject index

Related subjects

These subject pages bring together related projects, technical articles, reports, and evidence methods.

Project anatomy

Contract scope and delivery roles

Client / authority
Zeevonk Phase 1 C.V., a Vattenfall and Copenhagen Infrastructure Partners project
Delivery parties
DEME - intermediate monopile transport, marshalling services, transport and installation of 69 monopile foundations, and filter-layer placement, TKF - separate supply contract for approximately 162 km of 66 kV inter-array cable, Fugro - geotechnical and geophysical investigation partner identified by Vattenfall
Contract route
Zeevonk awarded DEME a substantial transport and installation contract for the phase 1 foundations. DEME uses 'substantial' as a value category but did not disclose the price. Zeevonk separately awarded TKF the design, manufacture, testing and delivery of the 66 kV inter-array cables; that announcement does not name the cable installation contractor.
Execution window
The amended permit defines phase 1 as 1,062.6 MW of wind capacity plus 6 MWp of offshore solar. Vattenfall schedules this phase for completion in 2029. Phase 2 adds 1,001 MW of wind, 50 MWp of offshore solar and 500 MW of system-integration capacity, with owner delivery planned for 2032. The DEME release does not publish foundation fabrication, marshalling, mobilisation or offshore installation dates.
Works package
Intermediate transport of monopiles, marshalling services for primary and secondary steel, transport and installation of 69 monopile foundations, and installation of a filter layer for scour protection. The package sits within the 1,062.6 MW wind component of phase 1, located 63 to 84 km off Bergen aan Zee. It does not, on the published evidence, include monopile fabrication, turbine installation, inter-array cable installation, the TenneT platform, offshore solar or the onshore hydrogen facilities.
Marine interfaces
The foundation sequence must join fabrication delivery, a still-unannounced marshalling base, intermediate transport, offshore lifting and piling, secondary-steel handling and filter-layer placement. Site investigations found strong currents, large sand formations and artificial seabed obstacles; Vattenfall also planned a 2026 unexploded-ordnance survey. The 69 turbine positions then need to connect through approximately 162 km of 66 kV inter-array cable to the TenneT offshore substation.
Commercial evidence boundary
The core foundation installation opportunity is no longer open at owner level. Remaining visible interfaces include fabrication and port logistics disclosures, vessel and feeder strategy, survey and UXO work, noise and ecological controls, cable installation, remaining scour-protection layers, as-built survey and acceptance. No source reviewed for this record publishes package value, installation productivity, port allocation or subcontract awards.

Project timeline

Material developments

Dated events that changed scope, counterparties, delivery, commissioning or operating status.

Open this project in the Change Log

DEME won the 69-foundation transport and installation package

The award fixes the principal offshore foundation contractor and includes marshalling, intermediate transport and filter-layer placement. Port, vessel, fabrication and mobilisation details remain unpublished.

Source

TKF received the phase 1 inter-array cable supply contract

The separate award covers about 162 km of 66 kV cable and accessories. It establishes the cable supply chain but does not identify the offshore installer.

Source

The amended permit separated Zeevonk into two licensed phases

The permit assigns phase 1 and phase 2 to separate Zeevonk entities and fixes their capacities at 1,062.6 MW plus 6 MWp offshore solar, and 1,001 MW plus 50 MWp offshore solar and 500 MW system integration, respectively.

Source

Evidence gap

What remains unverified

Outstanding evidence

  • Monopile and secondary-steel fabrication awards
  • Marshalling port and intermediate transport plan
  • Installation vessel, feeder spread and mobilisation date
  • UXO investigation and clearance status
  • Foundation installation method and underwater-noise controls
  • First monopile and filter-layer placement
  • Inter-array cable installation award and route preparation
  • As-built survey, scour completion and foundation acceptance

Related records 2

Reporting status

Award, confirmed confidence

Last checked 20 July 2026 across 6 cited sources. The dated timeline above carries the project events.

Last checked 20 July 2026 Cited sources 6

Sources and related records

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Source collections

Project sources 6