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Akita offshore wind links certified design to an active base-port workfront

Published 2 June 2026 Updated 28 July 2026 Publisher IMWO Region Asia Pacific Confidence Confirmed
Sea Challenger installation vessel selected for turbine installation on the Oga-Katagami-Akita offshore wind project

DEME Group / Japan Offshore Marine

The 315 MW Oga-Katagami-Akita project now connects certified 15MW-class foundation design to a visible Iijima Wharf workfront: a 2,500-tonne crawler crane and multi-axle transporters are on site, named contractors cover unloading and tower pre-assembly, and dedicated vessels are assigned for foundation and turbine installation.

Published scope and current milestone

The developer's official project page defines 21 Vestas V236-15MW turbines and a 30 June 2028 commercial-operation target. Its 1 July 2026 update confirms Japanese technical and port-standard compliance, with Kajima, COWI, Vestas, MHI Vestas Japan, and Arup in the design and certification chain. The developer's May and July site records place a 2,500-tonne DENZAI crawler crane and multi-axle transporters at Iijima Wharf and name Kamigumi and DENZAI for component unloading and tower pre-assembly. Penta-Ocean confirms Sea Challenger for turbine installation through Japan Offshore Marine and CP-16001 for foundation works under Kajima management. Offshore mobilisation, cable-laying award, installed foundations, and turbine delivery remain unreported.

Port delivery and operating implications

Japan's fixed-bottom offshore buildout depends on a tightly coupled domestic and international marine chain. The base-port evidence now identifies Sawakigumi, Kamigumi and DENZAI alongside Kajima, CP-16001, Japan Offshore Marine and Sea Challenger, but offshore mobilisation, the cable package, navigation controls, installation cadence, integrated testing, and grid handover still determine whether the June 2028 target is credible.

Evidence conclusion

Handover, readiness and service evidence

The base-port chain is now attributable rather than generic: Sawakigumi develops the base, Kamigumi and DENZAI handle unloading and pre-assembly, Kajima connects monopile design to CP-16001 foundation works, and Japan Offshore Marine supplies Sea Challenger for turbines. The open tests are berth acceptance, component arrival, cable award and vessel mobilisation.

Outstanding evidence

  • Iijima Wharf acceptance and first major-component delivery
  • CP-16001 foundation mobilisation and monopile sequence
  • Submarine-cable contractor and vessel identification
  • Sea Challenger arrival and turbine installation window
  • Navigation Safety Committee controls during marine works
  • Schedule movement against the 30 June 2028 commercial-operation date

Related records 1

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