Dogger Bank C, the third 1.2 GW phase of the 3.6 GW Dogger Bank Wind Farm off north-east England, has quietly become one of the more complete large offshore wind projects in UK waters. All of its foundations and its HVDC offshore substation are installed. What remains is the wind turbine campaign — and that is where the phase's schedule risk now concentrates.
Where the project actually stands
The phase-by-phase picture matters more than the headline "3.6 GW" figure:
| Component | Dogger Bank C status |
|---|---|
| 87 monopiles (~94,542 t) | Installed (final monopile September 2025, Seaway Strashnov) |
| 87 transition pieces (~32,917 t) | Installed (final TP late November 2025, Seaway Alfa Lift) |
| HVDC offshore substation jacket and topside | Installed May 2025 (Heerema Sleipnir) |
| 87 × GE Vernova Haliade-X 14 MW turbines | Not yet installed; campaign scheduled for 2027 |
Seaway7 completed the final Dogger Bank C transition piece on 27 November 2025, closing out 277 monopiles and 277 transition pieces across all three phases — a campaign the contractor describes as 554 foundation assets and more than a thousand lifts over three years.
The substation milestone came earlier. Aibel supplied the platform, with Hitachi Energy HVDC converter technology, and Heerema installed the jacket and then the topside roughly a week apart in May 2025, using the semi-submersible crane vessel Sleipnir. The platform is about 75 m by 50 m and 36 m high, on a four-legged jacket in roughly 23 m of water. Aibel's Dogger Bank design is unmanned and operated from shore, and the developer claims topside weight per MW is cut by up to 70% versus earlier platform generations — a useful detail for anyone benchmarking steel intensity in HVDC offshore substations.
The steel is already bought, built and in the water
For suppliers, the most important commercial fact is that Dogger Bank C's primary steel procurement is finished. The monopiles and primary transition-piece steel came from Sif, with Smulders (Eiffage Métal) producing secondary steel and assembling, coating and testing complete transition pieces. Eiffage announced the 87-foundation award in January 2022; the same consortium had earlier taken 190 foundations for Phases A and B.
The tonnages are unusually well documented for an offshore wind project, and worth recording because they set a useful per-unit benchmark:
| Item | Units | Total steel | Average per unit |
|---|---|---|---|
| Monopiles | 87 | 94,542 t | ~1,087 t |
| Transition pieces | 87 | 32,917 t | ~378 t |
| Combined foundations | 87 sets | ~127,459 t | ~1,465 t per foundation |
Monopile diameters run 8.0–8.4 m with lengths up to 73.3 m; transition pieces are 8.0–8.3 m in diameter and 27.4 m long. The jacket for the offshore substation was subcontracted by Aibel to Navantia Seanergies in Puerto Real, Spain, and loaded out in April 2025.
Anyone reading this as a live steel opportunity should recalibrate. Fabrication and installation are complete; there is no evidenced open structural steel package for Phase C. Future demand, if any, would come from operations, maintenance or repowering — none of which is currently tendered or confirmed.
Turbines: two vessels, two eras
The turbine campaign is the phase's active front, and the contracting here reveals how the industry's installation capacity is being re-tooled.
Jan De Nul's Voltaire was contracted for Dogger Bank C turbine installation in 2021 and has been deployed on the work. Cadeler has since added a second vessel to the phase: a firm contract to transport and install turbines at Dogger Bank C, with the newbuild Wind Apex scheduled to join the campaign in the third quarter of 2027. Offshore Wind reported the arrangement.
The choice of 2027 for a newbuild is not incidental. It reflects both vessel delivery schedules and a broader sequencing reality across the Dogger Bank complex, where turbine installation and commissioning have already slipped at Phases A and B. A separate vessel, Seaway Ventus, is working on Dogger Bank B turbines, and installation activity is being interleaved across the phases rather than run strictly in sequence.
That interleaving is a scheduling decision with commercial consequences. Turbine installation vessels are among the scarcest assets in offshore wind, and spreading a multi-phase campaign across overlapping vessel commitments lets the developer smooth demand — at the cost of tying up capacity that could otherwise serve other projects.
The context that matters: Dogger Bank A's troubles
Dogger Bank C cannot be read in isolation from the rest of the complex. Dogger Bank A has had a difficult construction and commissioning period, with blade failures in 2024 and further technical and safety issues during 2025, triggering turbine-installation and commissioning delays and knock-on transmission issues. UK government documentation on a proposed transmission licence exemption for Dogger Bank A indicates an extension into December 2026, and reporting suggests the first tranche's CfD deadline moved from November 2026 to July 2027. SSE's own preliminary results indicate turbine installation at Phase A was completed in February 2026, with commissioning expected to be substantially complete by the end of calendar 2026, and its REMIT disclosures point to phased turbine restoration from October 2026 to April 2027.
For Phase C, this matters in two ways. First, it reinforces why the C-phase turbine campaign is scheduled as late as 2027 — the developer has every reason to sequence commissioning resources and vessel time around the resolution of Phase A's issues rather than in parallel with them. Second, it means Phase C's commercial operation date carries more schedule uncertainty than a foundations-complete project might suggest. This is analysis, not a stated project position; the developer has not signalled a change to Phase C's own schedule.
What to watch
The remaining milestones are straightforward to list but not to deliver: completion of 87 GE Haliade-X 14 MW turbine installations, commissioning and energisation, first power and grid synchronisation, and commercial operation. The commercial and industrial interest now lies in three things:
- Wind Apex delivery from COSCO. The vessel's handover timing is the gating factor for the 2027 campaign.
- Commissioning performance across the complex. Phase C uses the Haliade-X 14 MW, a larger machine than the 13 MW units at A and B. A 15-year offtake PPA package for Phase C was signed in November 2021, so generation shortfalls land on the offtake arrangements, not just on the developer.
- Whether Phase A's issues prove design-specific or fleet-wide. The answer will shape how the C-phase turbine campaign is risk-managed.
Dogger Bank C is, in steel terms, a finished project waiting on its machines. That is a different risk profile from most offshore wind construction stories — and a reminder that once foundations are in the water, the critical path belongs to the turbine supply chain.