On the 9th, at the Jaeun High School pier in Hanun-ri, Jaeun-myeon, Shinan County, South Jeolla. After riding a small yacht for about 50 minutes across a sea packed with fish farms, 10 giant windmills came into view, lined up in two rows and slowly turning. About 9 kilometers northwest of the pier, this is Jeonnam Offshore Wind Power Phase 1 (Jeonnam 1), which generates electricity from sea winds and sends it to the mainland.
Jeonnam 1, which began commercial operation in Dec. last year, is the largest private-led offshore wind project in Korea. SK Innovation E&S and Danish energy investment company CIP invested equity stakes of 51% and 49%, respectively, to establish the joint venture Jeonnam Offshore Wind Power Co., Ltd. About 900 billion won was spent to install 10 offshore wind turbines rated at 9.6 MW (megawatts) each. Total installed capacity is 96 MW.
Measured at the point when the blade reaches its highest point in the sky, the wind turbine stands about 227 meters above sea level. The visible portion alone is almost on par with the 63 Building (250 meters). Below the sea surface, the substructure is driven an additional 40–60 meters. Each blade is 97 meters long and weighs 44 tons (t). The tower (column) embedded in the seabed weighs 600 t, and the nacelle, the heart containing the key components at the very top of the tower, weighs 520 t. The tower and nacelle together easily exceed 1,000 t.
Contrary to the expectation that the hefty blades would turn noisily, even up close only the crashing waves were loud. There was also a set-net fishing boat (a method that anchors both ends of a net to hold it vertically and uses tidal currents for fishing) not far away. Concerns had been raised that fish could not live near offshore wind farms due to noise and that fixed fishing gear such as set nets would be difficult to use, but what we saw that day was far from those worries.
Jeonnam 1 applied domestically produced equipment for about 75% of major components and installation gear—such as wind turbine towers, substructures, and transmission cables—by partnering with Korean corporations. In particular, it was the first among Korea's offshore wind projects to apply a monopile substructure. While cheaper than the traditional jacket type, it is highly affected by ground conditions, so no one had taken the risk to try it until now. After Jeonnam 1 succeeded in adopting monopiles, other offshore wind developers are moving to introduce the method.
The blades are designed to rotate nine times per minute and deliver maximum output when winds blow at 12 meters per second (12 m/sec). They are most efficient in fairly strong winds that make large tree branches sway. If winds intensify, such as during a typhoon, and reach 28 meters per second, rotation automatically stops for safety. That is because the generator could be damaged if the blade speed gets too high.
You never know when or how the wind will blow. The actual blade speeds varied, and some had stopped altogether. This aligns with the biggest drawback of renewables: intermittency. Output fluctuates with weather and time, making it hard to keep power supply steady. Jeonnam 1's capacity factor (the ratio showing how much it actually generated relative to installed capacity) is in the low-to-mid 30% range, but it varies widely by time and season. It rises to the 60% range at dawn and remains relatively high in winter.
By contrast, solar power has higher utilization during daylight hours and in summer. With massive electricity demand expected in South Jeolla due to the government's push for a Honam semiconductor cluster, the two renewables are expected to play complementary roles. Still, to reduce variability in renewables and supply power reliably, it is necessary to build large-scale battery energy storage systems (BESS).
The government is pushing to expand offshore wind infrastructure as one of the core tasks in its renewable-centered energy transition, leveraging the advantage of being surrounded by seas on three sides. Offshore wind is considered more efficient than onshore wind. The government expects that, if the Honam semiconductor cluster proceeds, South Jeolla will need an additional 6.3 GW (gigawatts) of power. That equates to four to five large nuclear reactors and exceeds last year's total power demand in the Honam region (about 5 GW).
Having successfully operated Jeonnam 1, SK Innovation E&S and CIP are also pursuing Jeonnam 2 and 3. Starting late next year, they plan to add the 2nd complex (399 MW) and the 3rd complex (399 MW), building out a large-scale offshore wind farm of nearly 900 MW by 2031. Taken together, the 1st, 2nd, and 3rd complexes amount to about nine times the current Jeonnam 1 (96 MW). That is about 64% of the capacity of one large nuclear reactor (based on 1.4 GW).
Full-fledged project advancement is set to proceed after participating in the fourth-quarter fixed-price offshore wind competitive bidding, depending on the results. The key is project cost. SK Innovation E&S estimates that offshore wind development expense has risen to about 4.5 trillion won for 500 MW of installed capacity. Higher interest rates have worsened project financing (PF) conditions, and rising raw material prices are also a burden. The exchange rate is another variable.
Kim Jin-cheol, a vice president at SK Innovation E&S, said, "The Jeonnam 2 and 3 blocks are set back from boundary lines of military training and ship traffic zones that require permits," and added, "If we are selected as a developer in the second-half fixed-price offshore wind competitive bidding, we can develop faster than other areas that require permits."
Among the core facilities of offshore wind turbines, the largest domestically made turbine currently is 10 MW. Jeonnam 2 and 3 plan to deploy 15 MW-class wind turbines, but none have been commercialized in Korea yet. Doosan Enerbility is preparing for assembly production in cooperation with Siemens Gamesa, but there is a possibility it will be less price-competitive than European products.
Chinese wind turbines are known to be about 40% cheaper than European ones. But there are concerns about security issues. While it has not yet been decided which company's turbines will be used for Jeonnam 2 and 3, the developers say they will exclude Chinese products for now.
The industry hopes that more public funds, including the Public Growth Fund, will flow into offshore wind projects. In fact, funding from the Public Growth Fund has been confirmed for the Shinan-Ui offshore wind project in South Jeolla. The industry argues that government support is needed to back early-stage projects until offshore wind power's unit cost falls enough to secure price competitiveness.
Currently, the levelized cost of energy (LCOE) for domestic fixed-bottom offshore wind is around 300 won per kilowatt-hour (kWh), which is considerably more expensive than large nuclear power (50–70 won/kWh). If generation costs are high, power procurement costs rise, which can increase pressure to raise electricity rates. For the government, a key task is how to enhance offshore wind's cost competitiveness.
In the United Kingdom, the unit cost of offshore wind power dropped sharply after cumulative installed capacity surpassed 4 GW. In Korea, cumulative offshore wind capacity is still only 0.35 GW. The government has set a goal to deploy 4 GW annually by 2030 and more than 25 GW cumulatively by 2035, but it remains uncertain whether actual installations will grow as planned.
Vice President Kim Jin-cheol said, "By the time Jeonnam 2 and 3 are completed, we expect to be able to supply power stably to the Honam semiconductor cluster," and added, "Once we reach a certain scale, the unit cost naturally falls, so we need the strength to endure until then."