The nation's electricity demand is expected to peak this week due to the hot weather and people returning from summer breaks.
According to the Korea Power Exchange, demand is likely to top 90-thousand megawatts.
It's possible the figures could surpass the previous record set last month, while the reserve ratio could plunge to as low as 5.4 percent.
In order to ensure stable supply, reserves should remain above 10 percent.
The energy ministry previously forecast power demand will hit its seasonal high in the second week of August.