Signal Transmission bottlenecks cut Korean coal plant utilisation from about 61 percent in 2020 to the 48 percent range

Summary

Large new coal and nuclear plants began commercial operation on Korea's east coast from 2017, but the transmission line to the capital region, originally due in December 2019, was delayed by local acceptance problems. Since 2022 the resulting bottleneck has forced curtailment of coal plants, which rank below nuclear and renewables in dispatch order, sharply lowering utilisation of east coast coal units. Solar capacity concentrated in the Honam region has also produced more power than the grid can carry. Between 2020 and 2025 nuclear and renewable generation rose 25.3 percent, while coal generation fell 13.0 percent and coal use for power 9.1 percent. The utilisation rate of coal plants dropped from about 61 percent in 2020 to around 55 percent in 2023 and to the 48 percent range in 2024 and 2025.