South Korea is scrambling for alternatives to coal-fired power to maintain sufficient base-load capacity, writes Evelyn Lee
South Korea's pledge to phase out coal-fired power generation by 2040 has thrown its energy strategy into sharp focus, exposing a looming 40GW capacity gap. With nuclear expansion stalling and renewables facing infrastructure hurdles, LNG has become the most likely bridge to fill the potential shortfall.
South Korea has formally confirmed its plan to retire 40 out of its 61 existing coal-fired units by 2040, following its declaration during the UN Cop 30 climate summit in Brazil last month to join the Powering Past Coal Alliance (PPCA) — a coalition of countries committed to ending coal use for power generation. The phase out timeline for the country's remaining 21 units — some of which were built relatively recently — will be determined through public consultation taking into account economic and environmental feasibility, and a detailed phase-out strategy is expected to be finalised next year, the PPCA says. This aligns with Seoul's intention to establish its 2026-40 long-term power plan by the end of next year.
The firm phase-out pledge leaves South Korea scrambling for alternatives to maintain sufficient base-load power capacity. Its current long-term power plan covering 2024-39 was established in February under the previous administration of then-president Yoon Suk-Yeol. It earmarked 28 aging coal-fired units with a combined 14.1GW of capacity for conversion to LNG, and 12 units with 6.8GW of capacity to transition to carbon-free generation, such as pumped storage, hydrogen or ammonia co-firing, all by 2038. The current administration under President Lee Jae-Myung has indicated it does not intend to allow plants to switch to ammonia co-firing, signalling a decisive break from earlier strategies that sought to keep coal in the mix under a low-carbon guise. In line with this, Lee's administration in October cancelled the second round of a clean hydrogen power generation bidding market, which would have subsidised hydrogen and ammonia co-firing under 15-year contracts.
Seoul searching
An accelerated coal phase-out alongside a ban on approving new nuclear reactors has led to growing expectations that South Korea will lean more heavily on gas-fired plants to maintain its power system at least until renewables capacity catches up.
The current electricity plan stipulates building two new 1.4GW reactors and continued use of expiring reactors, resulting in nuclear capacity rising to 35.2GW in 2038 from 26.1GW in 2025. But the Lee administration has ruled out building new reactors, although construction of reactors already under development can proceed as planned. The government has approved the restart of the 650MW Kori reactor 2, in line with the president's stance that expiring reactors may continue operating if safety standards are met.
But even with these measures, Seoul must identify more than 40GW of replacement capacity by 2040, based on information currently available. This is roughly equivalent to the country's entire coal-fired fleet, which has accounted for around 28pc of total power output this year. The government aims to expand South Korea's renewable energy capacity to 100GW by 2030 from a previous target of 80.9GW and current capacity of 37.9GW, but its renewables rollout continues to be constrained by insufficient transmission capacity upgrades, mainly driven by local opposition.
A law to accelerate grid projects came into force on 26 September, but progress is now being held up by local governments, which are reluctant to approve project permits in a bid to maintain positive public opinion ahead of municipal elections in June next year. Persistent grid bottlenecks have increased the country's reliance on gas-fired generation in recent years, as these plants are located close to the main demand centre around Seoul.
