As large electricity loads, including semiconductor facilities and artificial intelligence (AI) data centers, concentrate in the Honam region, expanding the power grid and ensuring its stable operation are becoming increasingly important.
Korea Electric Power Corporation, or KEPCO, is expanding its capacity to accommodate renewable energy by building new transmission infrastructure while introducing flexibility measures to make greater use of the existing grid. It is also pursuing measures to build substations proactively near major electricity consumers.
Honam semiconductor projects account for 6.2 GW of demand
On November 5, Kwak Eun-seop, head of the power system planning division at Korea Electric Power Corporation, identified semiconductors, physical AI and AI data centers as the three major project categories that will drive large electricity loads. Kwak was speaking at the Forum on Honam Semiconductor Megaprojects and Future Power Infrastructure, part of KEPCO's BIXPO 2026 at the Kimdaejung Convention Center in Jeonnam-Gwangju Integrated Special City.
Kwak Eun-seop, head of the power system planning division at Korea Electric Power Corporation, speaks at the Forum on Honam Semiconductor Megaprojects and Future Power Infrastructure at the Kimdaejung Convention Center in Jeonnam-Gwangju Integrated Special City on November 5.
Kwak explained that power supply plans for semiconductor industrial complexes submitted to KEPCO total about 15 GW. Of that, semiconductor projects in Honam alone account for about 6.2 GW of electricity demand.
“In the past, it was uncommon for electricity demand to arise in gigawatt units, but these days, whether for semiconductors or AI, demand of 5 GW or 10 GW is readily emerging,” Kwak said. “We are now in an era of large loads, when we must respond to electricity demand on a substantial scale.”
Demand from AI data centers is also growing rapidly. “Some applications for AI data centers are submitted in units of 1 GW,” Kwak said. “In addition to the capacity currently planned, further demand also appears likely to be substantial.”
With large electricity loads moving outside the Seoul metropolitan area, addressing regional disparities in power infrastructure was also identified as a challenge.
“Data centers exceeding 1 GW generally need to connect at 345 kV, but there are relatively few 345 kV substations outside the Seoul metropolitan area,” Kwak explained. “That is because demand has been concentrated in the metropolitan area, so more of the existing infrastructure has also been built there.”
KEPCO is therefore pursuing a program to build substations in advance in areas where large demand has been confirmed, with the aim of attracting electricity consumers. “A proposal has been prepared for the government to build 345 kV substations proactively outside the metropolitan area, even before firm demand emerges,” Kwak said. “We plan to proceed with government support and joint participation by local governments, advanced-industry companies and data center developers.”
“For AI data center developers, whether there is a 345 kV substation nearby is very important,” Kwak emphasized. “If the substation is 60 km away, building a new transmission line takes considerable time. Whether a substation is close to the site can determine its competitiveness as a location.”
Kwak assessed Honam as a region with sufficient electricity supply. “Honam generates about 1.3 times as much electricity as the region consumes, and in South Jeolla alone, generation exceeds twice its demand,” Kwak said. “South Jeolla has one of the highest levels of energy self-sufficiency in the country.”
Supply capacity is expected to increase further as additional renewable energy and combined-cycle gas generation facilities are installed. However, Kwak said community acceptance could become an obstacle when expanding transmission infrastructure to send locally generated electricity to other regions, including the Seoul metropolitan area.
“About 70 GW of renewable energy is scheduled to be installed in Honam, and transmitting the electricity produced to other regions requires a corresponding amount of transmission infrastructure,” Kwak said. “We expect considerable difficulties during transmission line construction, including residents joining together in opposition.”
Substations and greater use of existing transmission infrastructure
KEPCO will build substations where large demand has been confirmed.
Measures to make maximum use of existing facilities, rather than relying solely on transmission grid construction, are also being pursued. The idea is to use battery energy storage systems (ESS) and other measures included in the government's power grid innovation package to redistribute electricity flows concentrated at particular times and increase the capacity factor of existing transmission lines.
“We cannot simply wait until the transmission grid is completed,” Kwak explained. “The flexibility measures resulted from considering how to connect additional renewable energy using the existing transmission grid.” Kwak added: “Using battery energy storage systems to charge when electricity demand is concentrated and discharge when congestion eases allows us to use existing transmission lines more efficiently.”
Kwak explained that the measures aim “to accommodate more than 50 GW of additional renewable energy through the existing transmission grid.”
Maintaining stability as renewable energy expands
Kwak also stressed the need for structural changes to the power grid. Explaining that South Korea's electricity system had developed alongside economic growth over the past 70 years, Kwak said: “Over the past 70 years, generation capacity has increased 426-fold and electricity demand 314-fold.” Although the increase in transmission line length was relatively modest, the grid's ability to transport electricity had expanded by increasing transmission capacity and voltage.
However, Kwak assessed that a rising share of renewable energy also requires changes to how the stability of the existing power system is maintained. Conventional synchronous generators, including nuclear and coal-fired units, have used the inertia of rotating generators to absorb sudden changes in the power system. As inverter-based generation such as solar and wind increases, that inertial capability could weaken, Kwak explained.
“In the existing system centered on synchronous generators, rotational inertia absorbed the impact even when problems occurred with generators or the transmission grid,” Kwak said. “As the system shifts toward renewable energy, that capability could become insufficient.”
Kwak particularly emphasized the importance of technical measures to prevent a minor power system fault from spreading through a cascade. “A failure in one part of the power system can spread to the next piece of equipment,” Kwak said. “The first fault can happen at any time, but the key is to prevent cascading failures from progressing to the second stage.”
Kwak expected grid-stabilizing equipment, including synchronous condensers, batteries and grid-forming inverters, to play a greater role in addressing this. “In the future, synchronous condensers, batteries and grid-forming technologies will need to take on the role of ensuring power system stability,” Kwak explained. “The fundamental challenge goes beyond ensuring power quality to securing system inertia.”
Kwak also called for preparations against overvoltage and overfrequency. If a fault in renewable generation equipment causes inverters to disconnect from the grid, the balance between electricity supply and demand can change abruptly, causing voltage and frequency to rise.
“South Korea is relatively familiar with preparing for low-voltage and low-frequency conditions, but has comparatively little experience with overvoltage and overfrequency,” Kwak said. “As renewable energy expands, we must also prepare very carefully for overvoltage and overfrequency.”
“Going forward, establishing a system for reliably connecting and operating electricity infrastructure will be as important as securing electricity supply,” Kwak emphasized. “To respond to large electricity loads and expanding renewable energy, we must pursue transmission grid expansion, the use of existing facilities and power system stabilization measures together.”
Original Korean article: Edaily
English brief by Korea Wind Intelligence, koreawindintel.com
