Baltica 2 Offshore Substation: PTSC M&C Topsides Delivered
1. Background: Vietnam’s First European Offshore Wind Substation Delivery
In September 2026, PTSC Mechanical Construction Co., Ltd. (PTSC M&C), based in Vung Tau, Vietnam, completed the load-out and handover of four offshore substations for the 1.5 GW Baltica 2 offshore wind project in Poland. The shipment marks a defining moment in which Southeast Asian heavy-fabrication capacity formally entered the European offshore wind supply chain. Two of the four topsides are already being transported to Europe, while the remaining two have been loaded onto transport barges at PTSC M&C’s fabrication yard.
The Baltica 2 offshore substation delivery is significant on two fronts. First, it represents the first EPC-scale offshore substation topside delivery from Vietnam to a European offshore wind farm. Second, it confirms that European developers such as Ørsted are willing to source topside fabrication outside the traditional Nordic and Western European supply base, provided EPC partners with European credentials are involved in quality assurance, electrical integration, and commissioning oversight. For European developers, the strategic value is twofold: it shortens delivery schedules by overlapping fabrication and design, and it reduces topside cost by an estimated 15 to 25 percent relative to fully European-sourced alternatives.
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The Baltica 2 project, jointly developed by Polish utility PGE Group and Denmark’s Ørsted, comprises 107 offshore wind turbines and is scheduled to enter commercial operation in the fourth quarter of 2027. The four offshore substations form the transmission core of the project, collecting power generated by the wind farm and feeding it to the onshore grid via 220 kV AC submarine export cables. The topsides are designed as unmanned, automated platforms with remote operation capability from the onshore control centre in the Polish coastal town of Łeba.
2. Project Scope and Engineering Data
The Baltica 2 offshore substation programme involved approximately 16,000 tonnes of steel across the four structures. Each topside weighs approximately 3,500 tonnes, while individual module support frames weigh around 500 tonnes. Work included structural erection, anti-corrosion coating, piping, HVAC, electrical and automation integration, pre-commissioning, testing, and load-out. The coating application was carried out under controlled humidity conditions, with relative humidity maintained below 50 percent inside temporary enclosures — a critical parameter for the multi-layer epoxy and glass-flake coating system specified for marine C5-M corrosivity.
The delivery was executed under an EPC consortium between Semco Maritime (Denmark) and PTSC M&C (Vietnam). PTSC M&C’s scope covered onshore fabrication, architectural completion, and commissioning in Vietnam. Semco Maritime was responsible for high-voltage electrical design, protection and control systems, and offshore installation management.
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| Parameter | Value / Description |
|---|---|
| Total project capacity | 1.5 GW |
| Number of wind turbines | 107 |
| Number of offshore substations | 4 |
| Total steel quantity | ~16,000 t |
| Single topside weight | ~3,500 t |
| Module support frame weight | ~500 t |
| EPC consortium | Semco Maritime + PTSC M&C |
| Developer | PGE Group + Ørsted |
| Commercial operation date | Q4 2027 |
| Coating application humidity | <50 % RH (controlled enclosures) |
| Current shipment status | 2 units in transit to Europe, 2 units loaded on barges |
The topside electrical scope includes 220 kV HV switchgear, 66 kV MV switchgear, two 220/66 kV power transformers per topside (rated approximately 375 MVA each), STATCOM modules for reactive power compensation, and a full IEC 61850-based substation automation system. The transformer specification calls for ester-based ester fluid (FR3 or Midel 7131) for fire safety, since the topsides are unmanned and fire-suppression response time would be unacceptably long.
3. Offshore Substation Technical Requirements and Unmanned Operation Design
The Baltica 2 offshore substation is designed for largely unmanned and automated operation offshore. This imposes three principal design drivers on equipment selection and fabrication.
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- Corrosion resistance: The salt-spray marine environment requires coating systems applied under controlled humidity conditions below 50 % RH inside temporary enclosures. Surface preparation typically meets ISO 8501-1 Sa 2.5, with multi-layer epoxy-glass flake coating systems qualified to NORSOK M-501 for offshore atmospheric zones.
- Structural durability: Each 3,500-tonne topside must withstand wave, current, and vessel-impact loads over a 25-year design life. Fatigue analysis follows DNVGL-RP-C203, and the structural design complies with DNV-ST-0145 for offshore substations. The jacket foundation design is a separate scope executed by a European yard.
- Pre-commissioned electrical and instrumentation: Electrical and instrumentation systems are completed onshore before deployment, minimising the offshore commissioning window and weather-related risk. The pre-commissioning includes full protection relay testing, transformer heat-run tests, and SCADA integration with the onshore control centre.
4. Global Offshore Wind Substation Supply Chain Landscape
The Baltica 2 offshore substation delivery illustrates a structural shift in the global offshore wind supply chain. The traditional European EPC model — where a Nordic yard like Semco Maritime, Aibel, or Bladt executes the full topside scope — is now being augmented by hybrid models in which Southeast Asian yards handle structural fabrication and Nordic partners handle electrical integration and commissioning.
- Traditional European EPCs: Semco Maritime (Denmark), Aibel (Norway), and McDermott lead in high-voltage electrical and offshore commissioning expertise. These yards typically deliver topsides at a 1,800 to 2,800 EUR/tonne structural cost.
- Southeast Asian fabrication rise: Vietnam’s PTSC M&C and Malaysia’s MMHE leverage low-cost structural steel capacity to take on topside fabrication, with dry-tow transport by heavy-lift vessel to European installation sites. Structural cost is typically 25 to 35 percent lower than European yards.
- Middle East offshore foundations: Lamprell and similar yards supply jacket foundations, complementing Southeast Asian topside fabrication.
| Supplier region | Strength | Representative project |
|---|---|---|
| Nordic | HV electrical, commissioning | Semco Maritime, Aibel |
| Southeast Asia | Structural fabrication, cost | PTSC M&C, MMHE |
| Middle East | Offshore foundations | Lamprell |
The typical dry-tow transport cycle from Southeast Asia to the European North Sea is 35 to 55 days, depending on vessel class and weather routing. This logistic footprint is now considered commercially viable for offshore substation projects above 1 GW, where topside mass and volume dominate cost over transport distance.
5. Standards and Certification Requirements
The Baltica 2 offshore substation design complies with several major European and international standards. PTSC M&C, through its consortium partnership with Semco Maritime, satisfies the local-content and certification expectations of the European developer.
- IEC 61400-21-1: Wind power generation systems, measurement and assessment of electrical characteristics
- IEC 61936-1: Power installations exceeding 1 kV AC
- DNV-ST-0145: Offshore substations
- EN 1090-2: Execution of steel structures
- ISO 12944: Corrosion protection of steel structures by protective paint systems
- NORSOK M-501: Surface preparation and protective coating
- IEC 61850: Communication networks and systems for power utility automation
This arrangement is the first time a Vietnamese EPC yard has delivered an offshore substation under a European-recognised quality framework. PTSC M&C had to upgrade its welding procedure qualification records, non-destructive testing capabilities, and coating inspection protocols to meet EN 1090-2 Execution Class 3 and ISO 12944 C5-M corrosivity category — a multi-year capability build that signals the maturation of Vietnam’s heavy-fabrication sector.
6. Industry Outlook
The Baltica 2 offshore substation delivery is a representative event in the 2026 European offshore wind supply chain diversification wave. As follow-on projects such as Baltica 9 and Baltic Power move into fabrication, Southeast Asian yard capacity is expected to become a structural complement to the European offshore wind equipment supply chain, particularly for topside fabrication and module support frame delivery. The lesson for European developers is that hybrid EPC models combining Nordic electrical engineering with Asian fabrication capacity can shorten delivery schedules and reduce topside cost by an estimated 15 to 25 percent compared with fully European-sourced alternatives. The strategic question for 2027-2030 is whether this hybrid model scales to 2 GW+ projects such as the UK’s 3 GW Hornsea 4 and Scotland’s 2.6 GW Berwick Bank, where topside mass can exceed 5,000 tonnes and dry-tow windows become tighter.