Officials at Korea Electric Power Corporation's Gyeonggi headquarters in Yeongtong-gu, Suwon, Gyeonggi Province, monitor the power supply situation on Tuesday. [Herald Business DB]
Officials at Korea Electric Power Corporation's Gyeonggi headquarters in Yeongtong-gu, Suwon, Gyeonggi Province, monitor the power supply situation on Tuesday. [Herald Business DB]

South Korea is on the verge of breaking its all-time electricity demand record this week as extreme heat continues and major companies wrap up their summer vacation periods, returning workers to factories and offices.

Authorities had originally forecast peak summer power demand to reach 94.1 to 98.8 gigawatts during the third week of August, but demand already entered that range in the first week of this month.

According to the Korea Power Exchange's power statistics system, peak demand on Friday reached 95.321 GW, the highest level this summer.

That figure ranks fifth all time, behind Aug. 20, 2024 (97.115 GW), Aug. 25, 2025 (95.951 GW), July 8, 2025 (95.675 GW) and Aug. 19, 2024 (95.611 GW).

The supply reserve margin fell to 9 percent, dropping below the 10 percent threshold generally considered stable. Reserve capacity stood at 8.2 GW.

A power supply emergency alert is triggered when reserve capacity falls below 5.5 GW. Between 4.5 and 5.5 GW, a "Standby" stage is declared, followed by escalating alert levels based on operating reserve capacity: Attention (below 4.5 GW), Caution (below 3.5 GW), Alert (below 2.5 GW) and Serious (below 1.5 GW).

The Korea Power Exchange had forecast demand for the first week of August (Monday through Friday) at 89.5 to 93.4 GW, but relentless heat day and night pushed peak demand steadily upward — from 91.1 GW on Monday to above 95 GW from Thursday onward.

Total demand, combining the official power market with off-market sources, was estimated to have exceeded 104.2 GW between 2 and 3 p.m. on Friday. Total demand includes power market demand plus electricity from Korea Electric Power Corporation's direct power purchase agreements — mostly solar — and small-scale private solar generation outside the market.

Demand is expected to climb further. Authorities anticipate that industrial activity will recover as the summer vacation season winds down this week, gradually pushing electricity consumption higher.

Weather remains a significant variable. Officials said a prolonged heat wave and tropical nights could push demand to a new all-time high.

If cooling demand rises during the heat wave while overcast skies reduce solar output, the strain on the grid would intensify. The Korea Meteorological Administration expects the extreme heat — with daytime temperatures approaching 40 degrees Celsius — to ease somewhat this weekend, but forecasts that the heat index will remain around 35 degrees next week.

Authorities are on alert and stepping up management of the power supply situation.

Officials say supply can handle even a record-breaking demand level, however. The Ministry of Climate, Environment and Energy raised summer power supply capacity to 107 GW, up 2 GW from last year, and has prepared an additional 8.8 GW in reserve resources as a buffer against any shortfall.


oskymoon@heraldcorp.com