The Korea Power Exchange once again issued a warning over the nation’s electricity supply on Tuesday, for the second day in a row.

The “preparation” warning was declared at 10:22 a.m. on Tuesday as the electricity reserve margin temporarily fell below 4.5 million kilowatts, officials said.

The same measure had been taken on the previous day, as the daily temperature soared to a mid-summer level.

The warning was lifted later in the afternoon, after the KPX retrieved some 530,000 kilowatts by adjusting the voltage output at power plants.

“Yesterday, we only reduced 2.5 percent of the total output but expect the margin to rise to 5 percent today, due to the ongoing electricity supply crisis,” said an official of the KPX.

“In order to respond to the demands this week, we have to cut down the total electricity demand by 1 million kilowatts by the end of the day.”

In case the electricity inventory drops further to 3.7 million kilowatts, the KPX is to issue an “attention” warning, the next step in the phased warning system.

The nationwide commotion over energy was triggered by the sudden shutdown of two nuclear reactors last week. Citing faulty control cables and forged quality warranties, the Nuclear Safety & Security Commission not only halted the two disputed reactors but also suspended the resumption of two others which were due to resume operation within the year.

The escalating sense of crisis over electricity especially brought tension to government complexes and public organizations, which may have to cut off air conditioning during the summer heat wave.

According to the government buildings management office, all public buildings are to halt air conditioning from the moment that the nation’s electricity reserve level falls below 3 million kilowatts. This is a tighter standard than last year, when the cutoff line was 1 million kilowatts.

By Bae Hyun-jung (tellme@heraldcorp.com)