[Report] "A 66-Story-Tall Generator Rises"... Inside the Construction of Korea's Largest Nakwol Offshore Wind Power Plant

Assembly of Turbines After Installing 33 Monopiles
67% Completion Rate... Trial Operation to Begin by Year-End
Korean Flag Acquired After Taking Over Chinese Installation Vessel
Gaining Experience in Large-Scale Offshore Wind Power Complexe

Off the coast near Songido, Nakwol-myeon, Yeonggwang-gun, Jeollanam-do, Nakwol Offshore Wind Turbines have been installed. Photo by Heejong Kang

On the morning of October 28, after traveling for about an hour and a half from Hauri Port in Sinan County, Jeollanam-do aboard the offshore wind support vessel (CTV) Jebi 1, massive offshore wind turbine towers and blades assembled at sea came into view. The height from sea level to the top of the turbine is 116 meters, and when the blades, which have a diameter of 165 meters, are attached, the total height of the generator reaches up to 198 meters. This means that a single wind turbine is as tall as a 66-story apartment building.

The Nakwol Offshore Wind Power Complex, which began construction in March 2024, is currently at the stage of assembling towers and turbines after installing 33 monopiles offshore.

The Nakwol Offshore Wind project, led by Myeongwoon Industrial Development, had previously been halted due to controversy over the use of a Chinese installation vessel (WTIV). However, after acquiring the vessel this year and changing it to the Korean-flagged Hansan 1, the project gained momentum. In addition, the installation vessel Hyundai Frontier, manufactured by Hyundai Steel Industries, has been deployed to accelerate the work. As of October, three generators have been assembled, and the project has achieved a 67% completion rate.

It takes two to three weeks to install the monopile and the upper structure. At the current pace, the company expects to install eight turbines and begin commercial trial operations by the end of the year.

"Eight Generators to Begin Commercial Trial Operations by Year-End... Profits to Be Shared with 4,000 Local Residents"

On the day of the reporter's visit, the Hyundai Frontier was taking shelter due to bad weather, while only the Hansan 1 remained at sea, displaying its imposing presence. Jongyoung Jeong, CEO of Samhae ENC, the engineering, procurement, and construction (EPC) contractor for the Nakwol Offshore Wind Power Plant, explained, "When work is at its peak, a fleet of 50 vessels-including installation vessels, support vessels, and transport ships-operates at sea."

Jongyoung Jeong, CEO of Samhae ENC, the engineering, procurement, and construction (EPC) contractor for the Nakwol Offshore Wind Power Plant, is explaining the offshore wind turbine installation vessel (WTIV) Hansan No.1. Photo by Heejong Kang

The Hansan 1 is a jack-up installation vessel that can lower its hull to the seabed for operations, allowing it to remain at sea regardless of weather conditions. It is equipped with a crane capable of lifting up to 1,600 tons and can accommodate up to 100 people. Kim Wookjin, Executive Vice President of Nakwol Blueheart, the project developer, explained, "Currently, 70 people are stationed on board, and they are receiving operational training from the previous Chinese crew."

The Nakwol Offshore Wind Farm plans to install 64 turbines with a capacity of 5.7 megawatts (MW) each, aiming for completion in June next year. The total installed capacity will be 364.8 MW. The total estimated project cost is 2.3 trillion won, making it the largest offshore wind power project currently built or under construction in Korea. At present, the total capacity of offshore wind facilities in commercial operation in Korea is 325 MW. Once the Nakwol Offshore Wind Farm is completed, the total capacity will instantly double to 700 MW.

Once the Nakwol Offshore Wind Farm begins full commercial operation in June next year, it is expected to generate annual sales of 300 billion won from electricity sales. CEO Jongyoung Jeong stated, "Once profits are generated, we plan to distribute 4.5 million won annually to each of the 4,000 local residents through a profit-sharing scheme." The Nakwol Offshore Wind Farm recently signed a Renewable Energy Certificate (REC) contract with Korea South-East Power Company.

The offshore wind installation vessel Hansan 1 is installing offshore wind turbines at sea. Samhae ENC.

Collaboration with Over 100 Korean Companies... Military-Grade Cameras Installed on Generators

The Nakwol Offshore Wind Power project has faced controversy from the outset over the participation of Chinese companies. The main shareholder of Vensys, the turbine supplier, is China's Goldwind. The blades are also supplied by a Chinese company, and the external offshore wind cables are from China's Hengtong Optic-Electric. Regarding this, CEO Jongyoung Jeong explained, "Except for the turbines, blades, and external network, all other equipment is domestically produced," adding, "We are collaborating with over 100 Korean companies."

In fact, the towers used in the Nakwol Offshore Wind Farm are supplied by CS Wind, while the monopiles, which are the substructures, are provided by GS Entec. The steel plates used for the monopiles are produced by POSCO. The transition pieces (TP) connecting the towers and monopiles are supplied by Samil CNS. The ultra-high voltage power equipment used in the onshore switchyard and substation is provided by LS Electric.

The project developer, Nakwol Blueheart, is owned 51% by Myeongwoon Industrial Development and 49% by Thailand's B.Grimm Power. In response to some claims that B.Grimm Power is Chinese-funded, CEO Jeong countered, "B.Grimm Group is a company whose largest shareholders are descendants of German immigrants." Furthermore, the Nakwol Offshore Wind Farm has emphasized its contribution to national security by agreeing with the Ministry of National Defense to install military-grade cameras on its generators.

The offshore wind support vessel (CTV) Jebi 1, operated at Nakwol Offshore Wind Farm, is docked at Hauri Port in Sinan County, Jeollanam-do. Photo by Hee-Jong Kang

"Urgent Need to Develop Hinterland Ports and Expand Installation Vessels... General Bids Should Focus on Widespread Adoption"

Among the 14 operators selected in government offshore wind power tenders since 2023, Nakwol Offshore Wind Farm is the only project that has actually begun construction. As a pioneering operator, it has experienced numerous twists, turns, and trial and error. Since no company in Korea has previously installed a large-scale offshore wind farm, the experience gained from the Nakwol Offshore Wind Farm is a valuable national asset.

CEO Jeong suggested, "To rapidly expand offshore wind power in Korea, it is urgent to develop hinterland ports and secure installation vessels." He noted that a lack of infrastructure could lead to bottlenecks.

Myeongwoon Industrial Development is pursuing the second phase of the Nakwol Offshore Wind Farm, called Hanbit Offshore Wind, but failed to win the government tender held in the first half of this year. The wind power industry believes that the use of Vensys turbines, which are subject to controversy over Chinese involvement, was the reason for the failure. CEO Jeong proposed, "While public-led projects should focus on nurturing the domestic supply chain, general tenders should aim to lower the levelized cost of electricity (LCOE) and promote broader adoption."

◆Glossary

·Offshore Wind Support Vessel (CTV)=Abbreviation for Crew Transfer Vessel. A vessel designed to transport personnel and equipment to offshore facilities such as offshore wind farms. Unlike general vessels, the bow is designed flat to facilitate docking with offshore wind installation vessels.

·Offshore Wind Installation Vessel (WTIV)=Abbreviation for Wind Turbine Installation Vessel. A vessel that transports and installs the substructures, towers, turbines, and blades of offshore wind turbines from the port to the offshore site.

·Monopile=One type of offshore wind substructure. It consists of a single column, making it easy to manufacture and install. In contrast, substructures composed of three or four columns are called jacket-type substructures.