[Report] Visiting the 'Seonamhae Offshore Wind Farm'... Quieter and Easier to Install than Onshore Wind Power

Installation of 20 Wind Turbines with 60MW Capacity
Supplying 17.4% of Electricity to Gochang and Buan Counties... Powering 50,000 Households

[Asia Economy Reporter Moon Chaeseok] On the 5th, right after the Chuseok holiday, the Southwest Sea Offshore Wind Power Demonstration Complex at Gushipo Port, Sangha-myeon, Gochang-gun, Jeollabuk-do. Centered around an offshore substation installed 10 km away from the land, 20 wind turbines with a total capacity of 60 MW were installed. This site supplies 17.4% of the electricity for Gochang-gun and Buan-gun in Jeonbuk.

Arriving at the demonstration complex Gushipo Port after driving 75 km from Naju Station in Jeonnam, about 30 households are gathered there. Although the weather was clear, the wind turbines were so far away that it was difficult to see them with the naked eye without using binoculars or the zoom function of a mobile phone camera.

I went up to the observatory of the Korea Offshore Wind Power (Hanhaepung) Demonstration Center, where you can see all 20 wind turbines and the flow of the waves at a glance. Without binoculars, it was hard to visually confirm all 20 turbines. The waves were rippling, and no noise was heard.

First Domestic Offshore Substation... Also Increases Resident Acceptance

The Southwest Sea Offshore Wind Power Demonstration Complex located at Gushipo Port, Sangha-myeon, Gochang-gun, Jeollabuk-do. (Photo by Korea Offshore Wind Power)

At 10:24 a.m. when arriving at Gushipo Port, the weather was clear with a temperature of 18 degrees Celsius, but it was impossible to take a boat. If the incoming wave height exceeds 1.5 m, for safety reasons, boats cannot be taken to the wind turbines. Hanhaepung employees, who must finish maintenance by November at the latest, had to postpone the scheduled regular inspection of aviation obstacles that day.

In front of the turbines spaced 800 m apart, a square offshore substation resembling a gas cooling facility caught the eye. It is the first offshore substation built in Korea, a device that raises the voltage of 22.9 kV collected from 20 turbines to 154 kV so that longer internal and external submarine cable networks can be used. It is a facility that reduces transmission loss and lowers the cost of cable networks in the process of transferring electricity from the turbines to the land. The electricity generated by these 20 turbines in one year, 155 GWh, supplies 50,000 households (based on 4 persons per household) in Gochang-gun and Buan-gun, Jeollabuk-do.

View of the Southwest Sea Offshore Wind Power Demonstration Complex located at Gushipo Port, Sangha-myeon, Gochang-gun, Jeollabuk-do. The square device in the center is the offshore substation. (Photo by Korea Offshore Wind Power)

The Southwest Sea Offshore Wind Power Project plans to expand its scale after the first phase demonstration complex (project cost 371.8 billion KRW) to a 400 MW pilot complex and a 2,000 MW expansion complex. Currently, wind condition surveys and feasibility studies are underway to find a site for the second pilot complex project.

What are the advantages of offshore wind power compared to onshore wind power? According to Hanhaepung, offshore wind power has advantages such as ▲lower noise than onshore wind power, ▲easier installation of large turbines over 3 MW, and ▲more stable wind flow when there are few islands, unlike onshore wind power where the wind amount decreases as it climbs mountains.

They also succeeded in commercializing the 'suction bucket method' used to build foundation structures, reducing costs. The suction, which looks like a small lighthouse, is a pump installed on a large steel pipe (bucket) that discharges water to create a pressure difference inside and outside the pile to install the lower foundation structure. Unlike the conventional method of driving piles, it produces less vibration and noise, thus having less impact on the marine ecosystem.

The installation time was also reduced from 30 days to 1 day, compensating for the disadvantage of higher installation costs than onshore wind power. It is expected that about 180 billion KRW can be saved if 50% of the lower foundation structures of the Southwest Sea Offshore Wind Power pilot complex are supplied by suction buckets.

What makes the Southwest Sea Offshore Wind Power pilot complex different from other offshore wind farms such as Jeju Tamna, Hallim, Jeonnam Sinan, and Ulsan? The Southwest Sea Offshore Wind Power pilot complex has an average sea surface height of 7.5 m, which is relatively low, making foundation construction easier. If the sea surface is too low, installation vessels and barges carrying equipment may touch the seabed, increasing construction costs, but the sea surface height in the Southwest Sea is appropriate, so such costs are relatively low.

If fishing operations are permitted within the offshore wind power demonstration complex, it is expected that fishing for oysters, scallops, seaweed, and kelp will be possible. (Photo by Korea Offshore Wind Power)

The demonstration complex occupies a total area of 8.364 km², including the 7.68 km² area of the power generation turbines and the permitted area for shared water surface use. Securing the 0.684 km² of permitted use area was particularly difficult because fishermen who used to operate within the complex inevitably raised complaints. The reason the third phase project plan was set in 2011 but the first phase demonstration project was only comprehensively completed earlier this year is due to the slow progress of the project.

Measures were taken to increase resident acceptance by allowing fishing of oysters, scallops, seaweed, and kelp within the complex. In August, Hanhaepung became the first in Korea to allow fishing boats to pass through the offshore wind power complex.

After completing requirements from the Ministry of Oceans and Fisheries such as ▲securing safety equipment ▲establishing a monitoring system ▲managing fishing boat safety ▲and completing maritime system safety control training for about 20 demonstration complex employees, full-scale fishing operations within the complex are planned to begin within this year. However, safety measures will be put in place to prevent entry within 100 m radius of the turbines. Fishing within the complex will be allowed only for fishermen pre-registered with Hanhaepung.

Challenges to Expanding Competitiveness of Domestic Turbines

The area near Gushipo Port, where the Seonamhae offshore wind power demonstration complex is located. Nearby are residential houses and a street of sashimi restaurants. The sounds of the offshore substation and wind turbines 10 km ahead were not audible. (Photo by Moon Chae-seok)

It is also true that many challenges must be solved to grow into a large offshore complex on the GW scale. In the event of a strong typhoon with wind speeds over 70 km/h (20 m/s), especially at night, it seemed difficult to respond because the equipment is 10 km away from the land and boats cannot be launched if wave height exceeds 1.5 m. To activate the 400 MW second phase pilot complex, wind turbines of at least 5 MW must be produced.

Doosan Heavy Industries is developing a 5.5 MW facility, and about 70 of these turbines are expected to be installed in the second phase pilot complex. Doosan started developing an 8 MW large-capacity offshore wind turbine as a national project in 2018, with product development expected to be completed in 2022. In Europe, which is called one of the four major offshore wind power countries including the UK and Germany, 8 MW turbines are already commercialized, and 12 MW turbines are under development. According to the Korea Wind Industry Association, Doosan's installed capacity last year was 158,500 kW, accounting for only 10.64% of the domestic market share.

The government's goal of 'creating a 20 GW offshore wind power complex and 87,000 jobs by 2034' seemed challenging. A Hanhaepung official said, "We plan to enhance the competitiveness of domestic equipment and revitalize the industry through pilot and expansion complexes, supporting future exports as well."

This content was produced with the assistance of AI translation services.