Electricity Can't Be Transmitted Even When It's Generated... Renewable Energy's Real Bottlenecks [Energy Odyssey] (16)

III. The Dream of Electrification
Connection Delays and Output Curtailments Persist Despite Renewable Energy Growth
Transmission and Distribution Network and Substation Construction Delayed by Opposition from Residents and Environmental Groups
Urgent Need to Expand Infrastructure to Prevent an Iberian-Style Blackout

Editor's NoteSupply chain crises caused by the recent war in the Middle East and the government's mega-projects have made energy more important than ever. South Korea faces the difficult task of achieving energy security, carbon neutrality, and economic growth simultaneously, even as it relies on overseas sources for most of its primary energy. In this series of articles, reporters covering energy issues on the ground will examine a range of current challenges and seek alternatives.

The National Action and Gyeonggi Action for Reconsideration of the Yongin Semiconductor National Industrial Complex and Against the Construction of Ultra-High-Voltage Transmission Towers held a press conference on the 28th at the early construction site of the Yongin Advanced System Semiconductor National Industrial Complex, calling for work to be halted. Participants set up a protest encampment at the logging site and began a tent sit-in. 2026.10.28.

On October 28, on a mountainside near Hwagok Reservoir in Namsa-eup, Cheoin-gu, Yongin, Gyeonggi Province, a tent was set up at a site where trees are being felled to make way for the Yongin Semiconductor National Industrial Complex. A banner reading "National Action for Reconsideration of the Yongin Semiconductor National Industrial Complex and Against the Construction of Ultra-High-Voltage Transmission Towers" was hung on the tent.

The National Action held a press conference and announced that it would begin a tent protest that day. "There has been no sufficient verification or public discussion of key issues, including the project's necessity and feasibility, plans for supplying electricity and water, harm to residents caused by the construction of ultra-high-voltage transmission lines, and damage to forests and farmland," the group said. The press conference was attended not only by civic groups from Gyeonggi Province but also by resident committees from Gongju, Daejeon, South Chungcheong Province, and other listed areas campaigning to scrap transmission tower projects.

Electricity demand is rising sharply with the expansion of advanced industries such as semiconductors and AI data centers, but the power grid has not kept pace, causing bottlenecks across the country. These grid bottlenecks are, in particular, the biggest obstacle to expanding renewable energy such as solar and wind power.

The government is aggressively expanding renewable energy, but the grid lacks the capacity to accommodate it, resulting in frequent connection delays and output curtailments. Construction of transmission and distribution networks and substations continues to be delayed due to opposition from nearby residents and environmental civic groups.

Grid Capacity Saturated, Projects Waiting to Connect... 64.8% in Honam Alone

According to National Assembly audit materials from Kim Wi-sang of the People Power Party, as of May 2026, power generation facilities with a capacity of 38,065 megawatts (MW) had applied to connect to Korea Electric Power Corporation (KEPCO)'s grid. Of that capacity, 29,382 MW had completed grid connection.

Of the remaining 8,683 MW, about 41%, or 3,546 MW (approximately 3.5 GW), is waiting to connect because KEPCO's grid lacks capacity. Honam accounts for 2,298 MW (approximately 2.3 GW), or 64.8% of the capacity awaiting connection to KEPCO's grid. A significant portion of this is understood to be renewable energy.

Building a power plant does not mean it can immediately generate and sell electricity. KEPCO's grid must be able to accommodate the power. But the grid has failed to keep pace with the rate at which power plants are being built, leaving many of them waiting indefinitely.

Facing grid capacity saturation, KEPCO designated 205 substations nationwide whose capacity was full as "grid management substations" in May 2024. Of these, 164 are in the Honam region (103 in Gwangju and South Jeolla Province and 61 in North Jeolla Province), accounting for 80% of the total.

Even if a new power plant is built after obtaining a power generation business license, it cannot connect to KEPCO's grid if it is located in an area designated as a grid management substation zone. KEPCO said connection would likely be possible only after 2032, when grid reinforcement is completed. As the wait to connect grew longer, small-scale solar power operators became increasingly dissatisfied.

In response, the Ministry of Climate, Energy and Environment announced its "Power Grid Innovation Plan" on September 29, including a measure to lift the designation of grid management substations in the Honam region. The government said it would free up capacity through expanded flexible connections, the use of energy storage systems (ESS), and inspections of speculative project operators, then allocate that capacity as a priority to projects on the waiting list.

However, people on the ground have yet to feel the effects of these policies. Kim Sook, secretary-general of the Korea Photovoltaic Industry Association, said, "Local governments and KEPCO don't have accurate information on the ground, and we have yet to see any actual effects."

The government has announced that it will support connections for new operators starting next year, but solar power operators are not taking the promise at face value. Connection delays will be difficult to resolve without fundamentally expanding transmission and distribution networks.

Power grid shortages are holding back the government's ambitious Sunshine Income Village initiative. According to the results of the second round of applications for the initiative, announced by the Ministry of the Interior and Safety in early October, only 23 of the 436 selected villages, or 5%, had met the requirements sufficiently to move forward quickly. The remaining 414 villages, or 95%, were selected conditionally and needed to address issues such as site leases, financing plans, and grid connections.

Grid capacity shortages appear to be the reason for conditional selection in many cases. According to National Assembly audit materials from Lee Cheol-gyu of the People Power Party, 58 of the 86 villages selected in the first round of applications for the Sunshine Income Village initiative, or 67.4%, needed measures to reinforce the grid.

Transmission and Distribution Networks Holding Back Renewable Energy

To secure the grid capacity that is lacking, transmission and distribution networks and substations must be expanded. Electricity generated at power plants reaches end users via transmission lines, substations, and distribution networks. Transmission lines are power networks that connect power plants and substations at ultra-high voltages of 154 kilovolts (kV), 345 kV, or 765 kV. Distribution lines carry electricity from substations to consumers after its voltage has been reduced to 22.9 kV.

KEPCO draws up transmission and substation plans and builds transmission lines and substations in line with the projected electricity demand in the government's Basic Plan for Electricity Supply and Demand. Most power generation facilities are built in accordance with the plan, while construction of transmission and substation facilities is delayed, often because of opposition from local residents.

According to materials that Kim Wi-sang received from KEPCO, plans called for 7,266 circuit-kilometers (c-km) of transmission and substation facilities from 2017 to 2025, but only 2,202 c-km were completed, for a completion rate of just 30.3%. Construction of transmission and substation facilities was found to typically take more than nine years.

Distribution network construction has also been delayed. Since most solar power plants connect to distribution networks, expanding those networks is particularly important for the growth of renewable energy. However, of the 23 projects that broke ground in 2024, when the long-term distribution plan began, only 12 (52.2%) were completed. In 2025, only three of 35 projects were completed.

"Targets for renewable energy are rising as demand for clean energy surges because of AI and energy independence becomes more important, but infrastructure is not keeping up," said Kim Sook, secretary-general of the Korea Photovoltaic Industry Association. "Grid infrastructure is ultimately needed to reach 100 GW of renewable energy by 2030."

Expanding substations is also urgent to support the growth of renewable energy. KEPCO plans to resolve connection delays for a total of 3,417 MW over the five years from 2026 to 2030. It plans to address 2,314 MW, or 67.7% of the total, by building 30 substations. But substation construction has also ground to a halt in many places.

The Dong Seoul Converter Station in Hanam is a prominent example of the challenges involved in building substations. The project centers on moving the existing 345 kV outdoor substation equipment indoors and building a new 500 kV high-voltage direct current (HVDC) converter station on the site, substantially increasing transmission capacity. The station is expected to serve as a key gateway for sending large volumes of electricity generated on the east coast to the Seoul metropolitan area and the Yongin Semiconductor Cluster. However, the project has made no progress for two years because of resident opposition and the local government's refusal to grant permits.

Delays in expanding the converter station could disrupt plans to supply electricity to the Seoul metropolitan area and semiconductor industrial complexes. Coal-fired power plants on the east coast have seen their operating rates plunge because they cannot transmit electricity properly, resulting in annual losses of hundreds of billions of won. If construction of the converter station is canceled, more expensive liquefied natural gas (LNG) power plants will have to be operated, and the cost will ultimately be passed on to the public. In 2024, KEPCO estimated that if the project were to fall through, annual electricity procurement costs would rise by 300 billion won.

How to Prevent an "Iberian-Style Blackout"

At 12:33 p.m. local time on April 28, 2025, the power systems across mainland Spain and Portugal suffered a complete blackout. Some areas in southwestern France near the Spanish border also experienced very brief power outages. The event became known as the "Iberian Peninsula blackout."

In Spain, about 15 GW of power generation capacity disappeared from the grid in roughly five seconds after the incident began. Transportation, including high-speed rail, came to a standstill, while communications and financial services were disrupted. Factories halted operations, and hospitals had to use backup generators. According to the European Commission, about 44.6 million people in Spain and 6.4 million in Portugal were affected, for a total of 51 million people.

Portugal's transmission network was restored about 12 hours after the incident, and Spain's about 15 hours and 30 minutes afterward. It was recorded as the most serious blackout in Europe's power system in 20 years. Investigations to determine the cause began in earnest immediately after the incident.

Initially, many blamed the rapid growth of renewable energy. But the final investigation report released in March 2026 by the European Network of Transmission System Operators for Electricity (ENTSO-E), prepared with the participation of 49 experts about a year later, reached a different conclusion. The main cause was found to be not the rapid growth of renewable energy itself, but the lack of adequate infrastructure to manage it.

For the power grid to remain stable, voltage and frequency must stay within acceptable ranges. Conventional power plants, including fossil fuel and nuclear plants, generate alternating-current electricity at a consistent frequency using rotating generators. The inertia of these generators helps prevent sudden changes in frequency, and they can regulate voltage by supplying or absorbing reactive power.

By contrast, the output of renewable energy sources such as solar and wind varies according to weather conditions. Solar panels generate direct-current electricity, while wind turbines generate alternating-current electricity, but their output characteristics vary depending on factors such as rotational speed. As a result, solar power and many wind power facilities connect to the grid through power conversion systems (PCS), such as inverters. With appropriate control capabilities, these facilities can also help stabilize voltage and frequency.

The investigation found that during the Iberian blackout, voltage rose sharply after grid oscillations and the cascading disconnection of power generation facilities occurred amid insufficient voltage control capacity. When voltage rises, power generation facilities or grid equipment must absorb reactive power to bring it down, but control capacity at the time was insufficient. Some generation facilities failed to respond appropriately to the voltage rise, triggering a cascade of generator disconnections.

In particular, some solar power facilities operated at a fixed power factor, which does not actively regulate reactive power, and therefore did not contribute sufficiently to voltage stabilization. A fixed power factor is an operating mode in which electrical equipment is set to maintain a predetermined power factor.

In light of this, calls are growing in South Korea to expand the voltage control capabilities of power generation facilities and grid stabilization equipment in line with the growth of renewable energy. Preventing an Iberian-style blackout requires not only energy storage systems (ESS) to mitigate fluctuations in renewable energy, but also the ability to quickly supply or absorb reactive power when voltage fluctuates.

KEPCO operates its distribution network at a fixed power factor of 1.0. A fixed power factor of 1.0 means that 100% of the total electricity supplied is active power, which performs actual work. When power equipment operates at a high fixed power factor, there is not enough reactive power to regulate voltage, making it difficult to respond appropriately to sudden voltage rises or drops.

According to National Assembly audit materials from Kim Ju-young of the Democratic Party of Korea, only 1.2 GW (3.6%) of the 33.4 GW of solar inverters connected to KEPCO's power grid had high-voltage ride-through (HVRT) capability, which allows them to remain in operation even during overvoltage conditions. Facilities with low-voltage and low-frequency ride-through capabilities (LVRT and LFRT) totaled 15.3 GW (45.8%), less than half.

"Given that overvoltage was the direct cause of the 2025 Iberian Peninsula blackout, the government urgently needs to provide funding for performance improvements and expand grid stabilization facilities," Kim said.

This content was produced with the assistance of AI translation services.