The Taean coal-fired power plant in Taean County, South Chungcheong Province, planned to generate 175,042 gigawatt-hours of electricity between 2021 and June this year. It produced 131,452 GWh. The plant gave up an additional 43,590 GWh because transmission facilities could not absorb all the power it was capable of producing — equal to a quarter, or 24.9%, of its original generation plan.
Twelve power plants nationwide are falling short of their generation plans because of transmission grid problems, according to an analysis by the National Assembly Budget Office released on the 22nd. Over the past five years and six months, these plants failed to convert a combined 112,430 GWh of planned output into actual electricity. KEPCO, the sole buyer of their power, has paid more than 3 trillion won in compensation for forgone profits — payments made for volumes the plants were unable to generate.
The grid has become a constraint on generation because building transmission lines takes far longer than building power plants. A plant is built in one location and needs to resolve interests only within that area, while a transmission line must cross multiple jurisdictions, requiring the resolution of conflicts among various local governments and residents. Opposition to transmission towers is mounting as concerns over environmental damage and possible health effects from electromagnetic fields draw attention. Persuading residents is also taking longer as the perception spreads that host communities merely lend a corridor for electricity to pass through and gain no real local benefit from the power trade itself.
Industry officials put the construction period for nuclear power plants, which face the strongest resistance from residents, at roughly seven to nine years. Coal-fired plants take five to seven years, and solar installations, the quickest to build, take one to three years. Expanding the transmission grid, by contrast, takes about nine to 13 years. Plants are completed and brought online years before the lines needed to carry their output are finished, leaving them repeatedly unable to perform despite having the capacity. The budget office said grid projects "must go through site selection, land acquisition, environmental impact assessments and consultations with residents," and that delays "limit generation at power facilities, create additional costs and, in some regions, can affect the stability of electricity supply."
The 12 plants hit by grid problems face at least another year before their situations are resolved. A 500-kilovolt high-voltage direct current project designed to carry large volumes of power from the east coast to the Seoul metropolitan area has stalled in Hanam, Gyeonggi Province. KEPCO has reached agreements with residents in most villages along the route, but Hanam has refused to grant permits for the expansion of the East Seoul converter station, pushing back completion. The city has held firm, saying it cannot approve permits without the consent of residents. Because of the grid delays, seven power plants in the Gangwon region have absorbed a reduction of 22,310 GWh in output over five years and six months. With the holdup rooted in conflict, there are concerns that the expected resolution date of October next year could slip further.
The 345-kV Dangjin–Sinseokmun–Sinsongsan transmission line project is in worse shape. With disputes with local residents dragging on amid rumors about electromagnetic radiation, completion has been pushed back to December 2028, two years from now. That is a full seven years and six months later than the original target of June 2021. Over the past five years and six months, the Taean plant and four others that depend on this line have missed out on generating 90,121 GWh.
The resulting drop in generation efficiency does not stop at lost output. It feeds into the cost base for electricity rates and ultimately lands on ordinary consumers. According to KEPCO, payments for electricity actually generated fell to 8.9957 trillion won last year from 10.216 trillion won in 2023, while payments compensating for power that was never produced rose by 352.8 billion won over the same period. The budget office said the structure means "costs stemming from delays in grid expansion end up reflected in the cost base for electricity rates."
Industry voices say the fix requires changing the structure under which Korea builds generation facilities and transmission lines separately. Power producers build the plants, while KEPCO, the buyer of the electricity, builds the grid on its own. Lawrence Berkeley National Laboratory, under the U.S. Department of Energy, pointed to Korea's power generation system and advised that the country "should take a proactive approach that identifies where the grid will be needed in advance, then plans and carries out construction."
Because the root of the problem is a mismatch between where power is produced and where it is consumed — with generation concentrated on the east coast and other outlying regions far from the metropolitan area that uses the bulk of it — some argue the answer is local generation for local consumption, producing electricity in the areas that use it.