South Korea’s nuclear power output has surpassed official targets, reducing the country’s coal usage and energy import costs. The rate of growth has been attributed to fewer maintenance outages, the addition of new plant, and because existing reactors have been operating at full capacity.
State utility Korea Electric Power Corp (KEPCO) released figures that show the country saw an 8.7% year-on-year increase in output from nuclear power for the first half of 2025, which is nearly three times the 2.9% cited in the official forecast. The major contributor, alongside a reduction in outages for maintenance, was the start-up of the 1.4 GW Shin Hanul unit 2.
By contrast, the country’s coal fired output has fallen by a dramatic 16%. The shift towards nuclear has helped the country reduce its energy import costs, with the coal import bill falling significantly as import volumes reduce.
Nuclear power’s share of total generation in South Korea rose to 31.7% in 2024, up from 25.9% in 2019, according to KEPCO data. This increase has largely balanced the decline in coal’s share, which dropped to 28.1% from 40.4% over the same period.
Following the effects of the 2011 Fukushima disaster, when tighter safety checks and maintenance shutdowns were introduced, and the subsequent rise in coal and LNG (liquefied natural gas) fired generation, the country’s nuclear output averaged a rise of 6.1% per annum after power consumption stabilised in 2022. Since then the country, which has a population of 51 million, has been increasing its nuclear generation capacity as policy resistance to the technology diminishes.
GlobalData forecasts South Korea’s nuclear power generation will reach 222.7 TWh in 2035, registering a compound annual growth rate (CAGR) of 2.4% between 2024 and 2035.
However, nuclear growth has led, reportedly, to transmission constraints. Seunghoon Yoo, a professor in the energy department at Seoul National University of Science and Technology, was quoted by the Reuters news agency as saying: “Plenty of coal plants are sitting idle not by choice, but because there’s no spare capacity on the transmission lines to carry more power.”
