The nuclear power output of South Korea has surpassed official targets, decreasing the country’s coal usage and energy import costs.
According to data from state-run utility Korea Electric Power Corp (KEPCO), the country saw an 8.7% year-on-year increase in nuclear power output for the first half of 2025. This indicates three times increase from the official plan of 2.9% annual growth.
KEPCO’s data indicates that while nuclear generation saw substantial growth, coal-fired output experienced a sharp 16% decline.
The credit for the growth can be given to fewer maintenance outages, the addition of the 1.4 GW Shin Hanul #2 plant, and existing reactors operating at full capacity. This has further contributed to lower generation costs and a decrease in coal usage.
South Korea, with a population of 51 million, is Asia’s second-largest nuclear power generator after China. The country is increasing its nuclear generation capacity as policy resistance to the technology diminishes. The trend can be seen across Asia, with Japan restarting idled plants and India starting commercial operations for new reactors.
Despite tighter safety checks and maintenance shutdowns following the 2011 Fukushima disaster, which led to increased coal and liquefied natural gas use, Nuclear power output of South Korea has surged to 6.1% annually since power consumption stabilised in 2022.
President Lee Jae Myung, who took office in June 2025, has pledged continued support for nuclear power.
In 2024, Nuclear power’s share of total generation in South Korea rose to 31.7%, which is an increase from 25.9% in 2019, according to KEPCO data. This increase has led to a decline in coal’s share, dropping to 28.1% from 40.4% over the same period.
GlobalData forecasts South Korea’s nuclear power generation to reach 222.7 terawatt hours in 2035. This registers a CAGR of 2.4% between 2024 and 2035.
The shift towards nuclear has led the country to reduce its energy import costs, with overseas coal volumes and the coal import bill both falling significantly.
Seunghoon Yoo, a professor in the energy department at Seoul National University of Science and Technology, was quoted by the news agency: “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.”
Renewables, including hydropower, are also affected by these constraints. This contributes just over a tenth of annual power generation.
Power demand in South Korea has been driven by increased cooling requirements since 2022, while industrial demand has declined. The power demand growth at a slow rate has discouraged the operation of expensive gas-fired plants throughout the day, despite their proximity to Seoul.
Gas is increasingly used to manage volatility, with the Korea Power Exchange observing a pattern of gas plants operating during peak morning and evening hours.
Moreover, the electricity consumption by semiconductor manufacturers and data centres is increasing rapidly, but this has not significantly affected fuel procurement, according to South Korea’s energy ministry.
