With July temperatures in Seoul already surpassing last year’s peak of 36.4 Celsius degrees, an unprecedented heat wave continues to grip the country, pushing electricity consumption to midsummer levels. On July 8, Korea’s maximum power demand reached 95.7 gigawatts (GW), the second-highest on record. Power authorities project that demand will hit an all-time high in the second week of August.

At a government ministers' meeting on the 10th, chaired by Prime Minister Kim Min-seok, the Ministry of Trade, Industry and Energy presented its outlook and countermeasures for summer electricity supply. It forecast that peak demand would reach between 94.1 and 97.8GW between 5 and 6 p.m. on a weekday in the second week of August, when both air conditioners are typically in continuous use and temperatures are statistically higher than in July. If power demand does reach 97.8GW, it would surpass the previous record of 97.1GW set on August 20 last year.

However, the government stressed that even if demand reaches its projected peak, electricity reserves will remain at manageable levels. Authorities estimate that reserve capacity during the second week of August will be up to 8.8GW. In preparation for potential supply disruptions from heavy rains, typhoons, or extreme heat, the ministry said it has secured an additional 8.7GW of “emergency resources.”

Solar power, which now accounts for a larger share of energy production, has helped mitigate peak demand by supplying electricity outside of the power exchange market. On July 8, solar generation accounted for 20 percent of total demand from 11 a.m. to 1:20 p.m., and 15 percent until 3:35 p.m. According to a Korea Power Exchange official, “Solar operators consuming their own generated electricity reduces the overall demand on the grid.”

The gap between the hottest hours and the time of peak power demand is largely explained by solar energy partially meeting demand outside the power market.

While the hottest period is typically between 1 and 4 p.m., peak electricity usage now occurs between 5 and 7 p.m., when solar output drops and the gap is filled by gas power generation within the official market.

This pattern helps stabilize the System Marginal Price (SMP), the market electricity price determined by the most expensive production cost within a given trading period.

“When peak demand surges in midsummer, the system needs to secure backup facilities that might not otherwise be required,” said an official from the Korea Power Exchange. “Reducing in-market power demand helps stabilize SMP.” In other words, solar energy covering some of the load reduces the need for additional costly generation.

Although solar power is handling a growing share of peak summer demand, traditional sources like gas power still carry the bulk of the load. Gas generation is relatively quick to ramp up and less affected by weather. On July 8, gas plants supplied up to 36.2GW of electricity as of 5:10 p.m.

Lim Jae-min, Secretary-General of the Energy Transition Forum Korea, said, “Solar energy is playing a key role in preventing demand from exceeding 100GW during the hottest periods. Without it, we would have to rely entirely on gas power.” He added, “We need to increase the share of solar power, which already covers around 20 percent of demand during peak hours.”

Power authorities have designated a 72-day electricity supply management period from July 10 to September 19. During this time, a “comprehensive electricity supply monitoring center” will be operated in cooperation with related agencies to ensure stable power management.

Minister of Trade, Industry and Energy Ahn Duk-geun said, “Even with temperatures exceeding expectations, we are maintaining stable electricity supply thanks to sufficient reserves. We will remain vigilant and activate prearranged response measures promptly in the event of heatwaves, typhoons, or large-scale equipment failures, so that the public does not experience disruptions in power usage.”