A mismatch between power generation and transmission infrastructure — where plants produce electricity that cannot be delivered for lack of lines — is spreading to South Korea's core industrial complexes in semiconductors, petrochemicals and biotechnology. Factory startup dates are approaching, but the transmission grid projects essential to supplying power remain in early stages, raising concerns about large-scale disruptions to electricity supply.
The country's power grid is suffering a severe supply-demand imbalance, according to a report titled "2026 Status and Issues of Public Institutions" released by the National Assembly Budget Office on the 22nd. The imbalance is deepening as the expansion of interconnection lines carrying electricity from non-capital regions, where generation is concentrated, to the Seoul metropolitan area has been delayed. North Gyeongsang Province had a power self-sufficiency rate of 216% as of 2023, compared with 65% for the capital region. The greater problem is that this infrastructure bottleneck is now extending to transmission lines dedicated to advanced industrial complexes. Completion targets for key transmission projects serving major industrial complexes are arriving one after another, yet progress rates stand at just 1% to 20%.
The situation is most severe at the Yongin advanced system semiconductor cluster, set to become the world's largest chipmaking base. The project, which involves building 14 lines including the 345-kilovolt Sinpyeongchang-Sinwonju route, carries a total cost of 3.7 trillion won ($2.6 billion). The completion target is December 2036, but spending as of the end of 2025 totaled 19.4 billion won, a progress rate of just 1%. The government and industry have set startup targets for the Yongin cluster at 2027 for SK hynix's general industrial complex and 2029 for Samsung Electronics' national industrial complex, the latter assuming an accelerated launch.
Little progress can be expected for some time. According to the annual spending plan, outlays scheduled for 2026 through 2029 total just 49.7 billion won. By contrast, spending planned for after 2030 comes to 3.6451 trillion won, meaning 98.6% of the remaining project cost is concentrated in the period after 2030. The structure makes slow progress on grid construction over the next four years all but inevitable.
Other national industrial complexes face the same problem. The transmission project for the Yeosu national industrial complex, which includes the 345-kilovolt Sinyeosu branch line, targets completion in September 2030, but of its 8.4 billion won total cost, only 7 million won had been spent as of the end of 2025. The project tied to the Songdo bio cluster, including the 345-kilovolt Sinsiheung-Sinsongdo line, is budgeted at 330 billion won with a December 2028 completion target, but progress stands at 20%, with 65 billion won spent.
The core issue is the physical time construction requires. High-capacity transmission lines rated at 345 kilovolts take an average of nine to 13 years to complete. The government is seeking to shorten the overall construction period to nine years through a special law, but that falls short given the current pace. With completion targets for the Songdo and Yeosu complex grid projects only two to four years away, in 2028 and 2030 respectively, and progress only just past the 5% to 20% mark, finishing within the remaining time is effectively impossible, the assessment holds.
"Because construction remains in an early stage, there is a possibility that power supply will not be in place when demand materializes," the budget office said. "If grid expansion is delayed, generation constraints and the resulting settlement costs may arise." It added that "there is a need to review the construction progress and spending plans for transmission projects serving major demand sites, and to manage them so that the gap with the timing of demand does not widen."