South Korea's power demand increases to new record high amid heat wave

South Korea's electricity demand has increased to a new all-time high this week as the country has been suffering from the record-breaking heat wave, but the government ruled out any power supply disruptions on nuclear reactors and LNG-fired power plants.

"The government would make all possible measures to meet the power demand such as higher operation rates of nuclear reactors and LNG-fired power plants," an official at the Ministry of Trade, Industry and Energy said Aug. 14.

South Korea's peak power demand came to 94.6 GW at 6 pm Aug. 13, over the previous record of 94.5 GW set on Dec. 23, 2022 when the country was hit by a cold spell, according to the ministry.

The peak power demand also beat the previous summer season record of 93.8 GW set Aug. 5 this year and 93.6 GW set Aug. 7, 2023.

Despite the record demand, the country was able to supply electricity with no disruptions by providing 104.8 GW, helped by increased power production from nuclear reactors and LNG-fired power plants, the ministry official said.

"The country maintained electricity reserves of 10.2 GW with a power reserve ratio of 10.7%," the ministry official said, noting that the state-run power operator should have a reserve ratio of 10% or more in order to maintain a stable power supply and prepare for emergencies.

"If the power reserve ratio declines, several LNG-fired power plants that are currently under test runs will start commercial production earlier than scheduled," the official said.

Six nuclear reactors with a combined capacity of 5.05 GW are currently offline for maintenance, accounting for 19.4% of the country's overall capacity of 26.05 GW across 26 nuclear reactors, compared with 13.6% from the shutdown of four reactors a year earlier, according to state-owned nuclear power operator Korea Hydro & Nuclear Power Co.

The record-high power demand came as the country has been gripped by sweltering weather, with the average national temperature from June through August being well higher than usual.

The Seoul metropolitan area, home to half of the country's total population of 51.8 million, has experienced its 24th tropical night, marking the second-longest streak since 1907, which has boosted power demand even overnight.

A tropical night refers to a phenomenon when temperatures stay above 25 degrees Celsius, from 6 pm to 9 am the following day, according to the Korea Meteorological Administration.

The weather agency predicted that the ongoing heat wave may continue over the next weeks, potentially setting a new record for power demand.