South Korea island turns to ABB technology to stabilize its power grid in the transition to renewables

Korea Electric Power Corporation (KEPCO), the largest electric utility in South Korea, and ABB have signed a Memorandum of Understanding (MoU) to supply the country’s first high-inertia flywheel synchronous condenser to help maintain the robust operation of the power grid on Jeju Island. This project will play a vital role in maintaining the stability, reliability, and continuity of the electricity network as the island integrates increasing levels of renewable generation to meet its ambitious clean energy goals. The project is integral to the vision of Jeju’s local government to achieve net-zero emissions by 2035 through a transition to renewable energy and clean hydrogen.

Jeju Island, located 240 km south of the main Korean peninsula, is home to around 670,000 people. It is also a popular tourist destination, with over 15 million visitors each year. The island is rapidly expanding its renewable energy infrastructure, with the use of wind and solar increasing its share of the power mix.

The transition to renewables is creating a stability challenge for island grids, especially in terms of maintaining the frequency within closely-controlled limits. This is because historically, fossil-fuel powered turbines have provided the spinning inertia vital to maintain a stable power network. Now that they are being decommissioned, this essential inertia in the grid is decreasing, making it difficult to add more renewable resources without the risk of curtailment. KEPCO’s solution is to install synchronous condensers, large rotating machines that mimic the operation of coal or gas generators to provide an alternative source of spinning inertia. They are being deployed by ABB to reinforce power networks in many projects worldwide, notably on islands such as the Faroes, the Balearic, the Canary and now on Jeju.

The ABB synchronous condenser, rated at 50 megavolt-ampere reactive power (Mvar) and close to 500 MWs will be installed close to a high voltage direct current (HVDC) station in the north of Jeju where a subsea cable connects the island to the mainland power grid. Its key feature is a high-inertia configuration that couples the synchronous condenser with a large flywheel. This approach multiplies the instantaneously available inertia by several times to ensure that network frequency is held stable within the tight limits essential to maintain grid reliability, while the synchronous condenser also provides voltage stability.

Eun-Bo Sim, President of KEPCO Research Institute said, “The introduction of the ABB’s flywheel synchronous condenser system will greatly enhance the stability of the Jeju power grid. KEPCO is committed to providing sustainable energy solutions.”

Kristina Carlquist, Head of Synchronous Condenser Product Line at ABB Large Motors and Generators Division, said, “With ABB’s proven technology and designs compliant with Korean standards, this flywheel synchronous condenser system will significantly improve frequency stability in the Jeju power grid. Through this project, ABB will set the standards for flywheel synchronous condenser systems in South Korea. We look forward to continuing our technological collaboration with KEPCO to further enhance the future stability of the Korean power grid as it transitions to green energy.”

The Jeju Island synchronous condenser is being designed and manufactured by ABB in Sweden as part of a package that also includes engineering and commissioning. It is scheduled to be in operation by the end of 2026.

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