Concerns about blackouts are mounting as cold spells hitting the nation are expected to raise electricity consumption. Adding to the woe is the likelihood of shutdowns at more nuclear reactors which were found using substandard parts.

Electricity use surged Thursday when freezing weather swept the nation following Wednesday’s heavy snowfall. The day’s morning low for Seoul was minus 10.3 degrees Celsius.

The Korea Power Exchange said electricity consumption soared to 72.97 million kilowatts at 10:35 a.m., with the power reserve sharply falling to 3.75 million kilowatts.

The state-run electricity distributor, however, did not issue a preliminary warning as the reserve figure did not remain below 4 million kilowatts for more than 20 minutes. 

As of 11:30 a.m., the nation’s power reserve was 4.63 million kilowatts, about 6.44 percent. Earlier, the agency warned that the reserve could fall to 2.88 million kilowatts, an alert level.

The Korea Power Exchange said it could control power demand through an advanced warning made on the previous day while providing an additional 400,000 kilowatts of electricity.

“Today is the coldest day of this winter season, elevating electricity consumption for heating systems. We could avoid a power crisis but we still need to assess the situation,” said an official of the agency.

Experts say the current power shortage is largely driven by a series of shutdowns of nuclear power reactors that are responsible for generating more than 30 percent of the nation’s electricity production.

Of the total 23 power reactors that generate 20.72 million kilowatts of electricity, operation at six facilities has been suspended for repair.

On Wednesday, the Board of Audit and Inspection said it found that the Korea Hydro and Nuclear Power Co., the state-run nuclear power plant operator, last year bought 966 components that had fabricated test results. The parts are currently in use at the Gori nuclear power reactors in Busan. The government has yet to decide whether it will suspend the Gori reactors.

Earlier, the Ministry of Knowledge Economy last month shut down two reactors at Yeonggwang Nuclear Power Plant in South Jeolla Province due to the extensive use of substandard parts in the reactors.

The shutdown of two 1-million-kilowatt reactors, which together account for nearly 4 percent of the country’s total electricity supply, has undermined the government’s efforts to maintain the power reserve at above what it considers to be a safe level of 4 percent.

The ministry said replacing more than 7,000 substandard parts that were used in the two nuclear reactors under fake quality warranties will not be completed until at least the end of the year.

By Lee Ji-yoon (jylee@heradcorp.com)