"Ideally, we would supply all power with renewable energy. But given that Korea has key industries like semiconductors and must supply electricity stably, the task is to decide the levels for nuclear power plants and renewables, and how to coordinate the rigidity of nuclear and the intermittency of renewables."
Minister Kim Sung-hwan of the Ministry of Climate, Energy and Environment signaled that nuclear power is needed for a stable power supply even as he argued for expanding renewables, speaking at the "second policy forum on a desirable energy mix" held at the National Assembly Members' Office Building in Yeongdeungpo-gu, Seoul, on the afternoon of the 7th. Minister Kim said, "Renewables do not immediately affect climate change and are relatively safe, but the question is what to do when there is no sunlight and no wind. Korea's east-west length is short, so the hours of sunshine are short."
The forum was convened to discuss long-term power source composition, including the construction of two large nuclear reactors reflected in the 11th Basic Plan for Electricity Supply and Demand. At the end of last year, Minister Kim said that two rounds of debates and public opinion gathering on the two reactors would be reflected in the 12th basic plan. The ministry held the first policy forum on the 30th of last month.
While acknowledging the need for nuclear power, Minister Kim also voiced concerns. Minister Kim said, "Starting as early as this spring and fall, when electricity use is low, there is a possibility of conflict between nuclear and renewables, so the task is how to solve the rigidity of nuclear," but added, "That does not mean we can go another route by reducing renewables." Minister Kim said, "The Lee Jae-myung administration has promised to increase renewables to 100 gigawatts (GW) by 2030 from the current 35 GW and must deliver," adding, "We will seek an energy direction that takes into account electricity rates directly tied to Korea's industrial competitiveness."
Experts at the forum stressed that the rigidity of nuclear can be addressed physically and technologically. Joo Han-kyu, president of the Korea Atomic Energy Research Institute (KAERI), said, "Because nuclear has low generation costs, it is advantageous to use it as baseload power, so while output adjustments to meet time-of-day fluctuations in electricity demand—load following—are easy, the higher-cost LNG plants have been used for that," adding, "The latest reactor, the APR1400, is designed for load-following operation, and while output reduction is currently applied down to 80% power, preparations are underway to enable daily output reduction to 50% starting in 2032."
Lee Jung-ik, a KAIST professor, also said, "The issue of output control for nuclear is not physically or scientifically impossible; it has simply not been done for institutional reasons," adding, "Since Korea Hydro & Nuclear Power Co. (KHNP) falls under the ministry's purview, it is a matter of telling it to quickly develop output control technology." Lee continued, "Unlike nuclear, renewables have a physical limitation in that output cannot be controlled," adding, "Based on current data, the probability that wind power will be available when we want it is 2%, and solar is 10%. In the case of solar, if you ask 100 times, only 10 times would generation be possible."
There were also warnings that an energy policy based solely on renewables would be risky for Korea's industries. Kim Moo-hwan, Director General of the SK Innovation Energy Solution Division, said, "Power demand driven by artificial intelligence (AI) is astronomically large beyond imagination, and in advanced industries like semiconductors, electricity must not be supplied from a single source alone," adding, "From the perspective of corporations that are large power consumers, they must choose comprehensively among the absolute scale of power, flexibility, and build time, so they cannot select only one power option."
Kim cited U.S. corporations such as Amazon and Google as examples. Kim said, "Global corporations seek not only renewables but also LNG generation as baseload power, and in the mid to long term, a transition to nuclear and small modular reactors (SMRs), and to next-generation nuclear," adding, "Large-scale baseload is shared between LNG and nuclear, while renewables are integrated at levels the grid can handle, and balance is achieved using a diversified energy portfolio."
There was also the view that the expansion of renewables requires considering the potential for higher electricity rates. Lee Seo-hye, head of E-Consumer, said, "Expanding renewables is ideal, but higher electricity rates could burden consumers," adding, "From the consumer's perspective, power must be clean while the expense remains reasonable. There are various resources to secure flexibility, so we should optimize them."
The nuclear industry also proposed ways to leverage renewables. Joo said, "If you mix nuclear, with a generation cost of 60 won per kilowatt-hour (kWh), and solar linked with energy storage systems (ESS), at 180 won, at a 50-50 ratio, the generation cost would be 120 won, which is a reasonable generation cost," adding, "For solar facilities above a certain scale, it would be desirable energy mix policy to mandate installing ESS capable of storing about half of daily generation, and to expand solar capacity while keeping nuclear and solar shares equal."