Developers seeking to build solar plants in the Honam region have been waiting indefinitely since June 2024, when the local grid reached saturation and could no longer accommodate new connections. The government recently cleared out fictitious operators with no real intent to build and allowed some connections, but most came with conditions requiring grid reinforcement. That bottleneck has fueled warnings that South Korea cannot reach 100 gigawatts of renewable capacity without fixing its power network.
The problem is that building new transmission lines is slow because local residents strongly oppose the projects. Grid delays have become the single biggest obstacle to expanding renewable generation.
The core of the grid innovation package the government announced on Sept. 29 is to make transmission connection rules more flexible and thereby allow more renewable generation to plug in. Unlike nuclear or coal plants, solar farms generate no more than 70% to 80% of their rated capacity even during the most productive hours of the year. Their average utilization rate stands in the mid-10% range. Under the current system, which uses rated capacity as the benchmark, new plants can be turned away even when the grid still has room to spare.
The government will therefore permit new solar plants to connect even where distribution capacity is already full. To avoid straining the network, output curtailment will be mandatory once actual generation reaches rated capacity. Specifically, the maximum connection capacity for standard distribution lines will rise to 16 megawatts from the current 14 megawatts, and the cap for transformers will rise to 60 megawatts from 50 megawatts.
Plants paired with energy storage systems that can limit their own output above a set level will be allowed to connect regardless of rated capacity. "Unlike large plants that send electricity through the transmission network, solar plants connect to the distribution network and have placed greater strain on the system," a government official said. "Taking that into account, we plan to include a separate plan for building energy storage systems tied to substations and the grid in the 12th Basic Plan for Long-Term Electricity Supply and Demand."
The government will also adjust connection rights held by fictitious developers with no real intent to build, a practice criticized as squatting on the grid. Offshore wind developers, whose projects take considerable time to build, are the main target this time. "Offshore wind developers in the Honam region hold connection rights for about 15.8 gigawatts through 2030, but we expect only about 3 gigawatts to actually be used," a government official said. "Developers connecting after 2030 can use the grid as it is reinforced later, and we intend to redistribute roughly 10 gigawatts of connection rights to projects that can proceed right away."
For the period after 2031, connection rights will be allocated on the assumption that only about 67.2% of permitted projects actually go forward, given that renewable projects face permitting delays and business uncertainty. In effect, connection rights will be overbooked by a set margin above actual transmission capacity. Connection rights are currently allocated on a first-come, first-served basis, and the package also includes a plan to give priority to projects that win fixed-price competitive auctions.
Through these steps, the Ministry of Climate, Energy and Environment aims to expand transmission network capacity as of 2030 to 171 gigawatts from 119 gigawatts, an increase of 52 gigawatts. New plants will also be allowed to enter parts of the Honam and Chungcheong regions starting Oct. 1, areas where entry had been suspended since June 2024 after substations there were designated as grid-managed. Connection limits in Gangwon State are set to be lifted in the first half of next year, timed to the completion of the high-voltage direct current link between the east coast and Sin-Gapyeong.
Experts advised focusing on building up grid management capability to support these measures. "The existing approach to operating the power network has been excessively rigid," said Yoo Seung-hoon, a professor of energy policy at Seoul National University of Science and Technology. "Output curtailment is already well established, so operating the rules more flexibly is a desirable policy direction." Yoo added: "That said, this will inevitably increase the workload for the Korea Power Exchange, which manages supply and demand, and for KEPCO, which handles the distribution network. Resources need to be invested so that management can be handled efficiently using artificial intelligence, and staffing needs to be expanded substantially."
