GS Entec Triples Monopile Capacity in Ulsan: What 150,000 Tonnes a Year Actually Means for Asian Offshore Wind Supply

GS Entec held the completion ceremony for its dedicated monopile facilities at the Yongjam Works in Ulsan on 26 October 2026, roughly two years after breaking ground and after a capital commitment of about KRW 300bn (≈US$210m). Annual monopile capacity at the site rises from 40,000 to 150,000 tonnes, a factor of 3.75, and the plant now quotes monopiles of up to 11 m diameter, 100 m length and 2,500 t unit weight — the dimensions required for 15 MW-class and larger turbines.

The trade-press announcement is short and corporate. The more useful reading is structural: this is the first time a Korean heavy-equipment fabricator has built a dedicated, automated monopile line rather than bolting offshore-wind work onto general fabrication capacity, and it is being done under licence from Sif, the Dutch foundation specialist. That combination matters more than the tonnage.

What was actually built

Yongjam was a chemical-equipment and pressure-vessel works. The conversion — rather than a greenfield build — is the strategic point: GS Group's chairman framed it publicly as redeploying chemical and heavy-vessel fabrication competence into renewable-energy infrastructure. The physical assets involved (large-format rolling, thick-plate welding, heat treatment, heavy handling and quayside access at a site that abuts the sea) are exactly the ones monopile manufacture demands, which is why European fabricators such as Sif, EEW and Bladt historically grew out of shipbuilding and process-equipment backgrounds.

A useful capacity check, using company and press figures:

Note: the length figure is inconsistent across sources (the company's own site still says 110 m), and the 160 mm figure refers to plate-handling capability, not a typical monopile wall thickness. Treat the website data as the pre-conversion baseline and the press data as the post-upgrade claim; neither has been independently audited.

The order book tells you how fast 150,000 tonnes fills up

The most instructive number is the Taean contract. Signed on 30 September 2026 with the Taean offshore wind project (504 MW), it covers 37 monopiles totalling about 51,000 t — an average of roughly 1,380 t per unit, consistent with the ~1,650 t installed-unit class cited at the plant. Production starts July 2027, with staged deliveries to end-August 2028.

Analysis: one mid-sized Korean project absorbs about 34% of a full year of nameplate capacity. Two more comparable orders would effectively book the plant for 2027–2028. At ~1,650 t per unit, 150,000 t/yr is roughly 90 large monopiles a year — enough to serve perhaps 1.5–2 GW of 15 MW-class offshore wind annually, depending on water depth and site conditions.

That arithmetic cuts both ways. It shows the plant is not overbuilt relative to a plausible Korean pipeline, but it also shows there is little room for the marketing narrative of serving Korea, Japan, and Australia simultaneously without a second line or a second site.

Implied unit price on Nakwol: roughly KRW 3.1bn (≈US$2.2m) per monopile. That is a useful benchmark for anyone modelling Korean foundation pricing, and it sits broadly in line with European monopile pricing for comparable sizes.

Sif's licence is the real technology transfer

The Sif relationship is not a courtesy mention. Sif and GS Entec signed a final cooperation agreement on 20 September 2023, following a 2022 framework, converting GS's Ulsan facilities to monopile and transition-piece manufacture. Reporting and Sif's own annual report indicate the arrangement includes a ten-year, mutually exclusive Asian licence, use of the Sif trademark and transfer of intellectual property — terms I have seen described in secondary sources but could not verify verbatim in the primary filings. Sif's CEO Koen Bogers attended the ceremony, which is a reasonably strong signal of how the Dutch company views the partnership.

Why this matters for the wider market: Europe's monopile supply chain is concentrated in a handful of fabricators (Sif, EEW SPC, Bladt, Steelwind, Haizea and a few others), all of which are capacity-constrained and exposed to European labour costs and yard congestion. A licensed Asian producer using proven European design and welding procedures is the most credible route to adding non-European capacity without a multi-year learning curve. The flip side is that Sif has effectively created a competitor in the markets it cannot easily serve from Rotterdam — a classic licensor's trade-off, and one that becomes commercially awkward if Korean yards start bidding into European projects or into Japanese projects where Sif would otherwise have exported.

The demand question: Korea is real, Japan and Australia are not yet

Korea's offshore wind programme has repeatedly slipped, but the pipeline is now visibly converting into steel. Nakwol has moved from foundation delivery to installation; Taean has contracted its monopiles two years ahead of construction start. GS Group has publicly referenced ambitions across nine offshore wind projects in Korea and Japan by 2030 — a corporate target rather than a contracted backlog.

Japan remains the larger prize but the harder one. Japanese projects have moved slowly through the government's auction rounds, and Japanese fabrication capacity for large monopiles is thin. A Korean supplier with a two-hour sea freight advantage, a common-standards environment and a proven reference list is a natural beneficiary — but Japanese developers have shown a strong preference for domestic content where it exists. Australia is a longer shot still: its offshore wind zone development is at an early stage, and distances from Ulsan are large enough that transport economics for 2,500 t monopiles becomes a serious constraint. Expect Australia to be a marketing line rather than an order book line before 2030.

The nearer-term competitive dynamic is domestic. Hyundai Steel, POSCO and other Korean groups have their own offshore-wind foundation ambitions, and the plate supply for Nakwol came from POSCO and Hyundai Steel. GS Entec's expansion strengthens Korea's position in fabrication but does not change the fact that the country remains dependent on domestic plate for thick-wall, high-strength steel — a segment where Korean mills are competent but where European monopile specifications (often 355–420 MPa normalized or TMCP plate at 80–120 mm) are demanding.

What to watch

1. Taean execution. Delivering 51,000 t of monopiles between July 2027 and August 2028 is the plant's first real test at scale. Any slippage would be read as evidence that the ramp-up was premature.
2. The second and third orders. The plant needs two more Taean-sized contracts to be comfortably full. Watch Korean Round 2/3 projects and any Japanese award to a Korean EPC consortium.
3. Sif's calculus. If GS Entec starts exporting to markets Sif would otherwise serve, the licence terms will be tested. Sif's own capacity expansion in the Netherlands suggests it is betting the Asian market is large enough for both.
4. Transition pieces. The Yongjam site was converted for both monopiles and TPs. TP capacity is a separate bottleneck in Asian projects and is often underappreciated in capacity announcements that focus on monopile tonnage.

Bottom line

GS Entec's Yongjam completion is a genuine step change in Asian offshore-wind foundation capacity — the first dedicated, automated, European-licensed monopile plant in the region, sized at roughly 90 large monopiles a year and backed by a KRW 300bn commitment. It is also a bet that Korean project flow will accelerate enough to fill it and that Japanese demand will open before 2030. The tonnage is impressive; the order book, not the ceremony, will determine whether the bet pays.