[Report] "Challenging Zero Downtime"... Inside the Installation of Unison's 10MW-Class Offshore Wind Turbine Prototype

Prototype Installation by July, Mass Production Preparation by June Next Year
Gearless System and Redundancy for Key Components Minimize Failures
Component Localization Rate Achieves 60%
Preparing to Enter the Japanese Floating Offshore Wind Power Market

Unison is installing a 10MW-class offshore wind turbine prototype at the Yeonggwang Wind Power Complex. Photo by Heejong Kang

"We have implemented redundancy for key components such as the yaw and pitch drives, controllers, and sensors. This means that even if a problem occurs with one component, the wind turbine can continue to operate."

On May 26, at the Yeonggwang Wind Power Demonstration Complex located in Sangsa-ri, Baeksu-eup, Yeonggwang-gun, Jeollanam-do, Johyuk Bang, Executive Director of the Unison Wind Power Research Institute, emphasized the competitiveness of Unison’s 10-megawatt (MW) class offshore wind turbine, stating, "We have strived to reduce downtime—the period during which equipment cannot operate normally due to malfunction—to zero."

That day, Unison was installing a 10MW-class offshore wind turbine prototype at the Yeonggwang Wind Power Complex. Atop the massive tower, the nacelle (the structure that houses the generator and other major components) and the hub (the unit connecting the blades to the nacelle) had already been assembled. Workers were busily preparing to assemble the blades as the final step.

On the ground, a 102.2-meter-long, 50-ton blade and a massive crane capable of lifting up to 1,600 tons were on standby for assembly. Although the weather was relatively clear that day, strong winds prevented the assembly work from proceeding. Once the blades are installed, the rotor diameter will reach 210 meters. This is why Unison named its 10MW-class offshore wind turbine 'U210.'

The development of the U210 began in 2018 as a national project, with approximately 70 billion won invested, including private capital from Unison and others. In February of last year, it received design certification from the international certification body UL, and completed manufacturing evaluations by the Korea Energy Agency and international certification authorities.

The installation of the prototype is the final stage before commercialization. Unison plans to complete the installation of the prototype by July and verify its performance through commissioning in an actual offshore environment. During this process, the company will collect operational data and experience, and pursue commercialization after obtaining UL type certification and KS certification. Unison anticipates that it will be able to begin mass production after June next year.

Unison's initial target is the 400MW Southwest Offshore Wind Power Project. Although the project was selected in the government’s fixed-price wind power contract bidding in the first half of last year, the choice of turbine has not yet been decided. Korea Offshore Wind Power, the operator of the Southwest Offshore Wind Power Project, plans to sign a preferred negotiating supplier agreement this year with one of the domestic 10MW-class turbine manufacturers through a separate tender process. Unison is in fierce competition with Doosan Enerbility.

Johyuk Bang, Executive Director of Unison Wind Power Research Institute. Photo by Heejong Kang

The U210 has been developed as a direct drive, gearless system that eliminates the gearbox, which is prone to failure during operation. By reducing the number of components, the durability and reliability of the turbine have been maximized.

Executive Director Bang commented, "We have secured excellent business viability with a design lifespan of 30 years, which is five years longer than the industry standard of 25 years. By applying a redundancy system to key components, we have minimized downtime in offshore environments where access is difficult."

Unlike onshore wind turbines, where repairs are more feasible, offshore turbines must be designed to require as little maintenance as possible, as repairs are much more difficult if a failure occurs at sea. Prolonged downtime leads to lower operating rates, which directly impacts profitability.

Additionally, the U210 features two separate 5MW-class stators. Even if one side fails, it can continue to operate at 5MW output. Its IP55-rated waterproof and dustproof design protects against damage from seawater or salt ingress.

Unison also plans to enter the floating offshore wind power market with this product. Executive Director Bang explained, "For floating offshore wind power, we believe that 10MW-class turbines are more suitable than the 14-15MW class. We are currently discussing collaboration with Japanese floating offshore wind power operators."

Since the U210 has been developed as a national project, Unison has increased the localization rate of its components to 60%. Yaw bearings, pitch bearings, generators, transformers, and towers have all been localized. Executive Director Bang added, "To accelerate development, we imported the blades from China. However, if domestic companies are able to supply blades by the time mass production begins, the localization rate could be increased to 80%."

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