Korea is about to write down the size of its own grid problem

Korea's Ministry of Climate, Energy and Environment said on the 15th that it will hold the fourth and fifth public policy debates on the 12th Basic Plan for Electricity Supply and Demand on the 20th, at Seminar Room 3 of the National Assembly Members' Office Building, with the fourth session starting at 10 a.m. ^[1]. The session that afternoon is where a revised 2040 demand forecast gets put on paper ^[2], and it matters because the plan is the top-tier framework from which generation capacity and transmission build-out follow ^[3].

The number being replaced was not conservative. In April the ministry put 2040 peak annual demand at 131.8 to 138.2 GW ^[4], against recent summer peaks of roughly 95 to 97 GW ^[5], which the ministry itself described as demand jumping more than 40% in about 15 years ^[6]. Two months after that forecast the government announced three national projects: four semiconductor fabrication plants in the southwestern region, early construction of the Yongin semiconductor cluster, and large-scale AI data centers ^[7]. The additional generation capacity for those three alone comes to 24.7 GW, which the ministry equates to 18 nuclear reactors of 1.4 GW each ^[8].

Run the arithmetic and the scale is clearer than the framing. That 24.7 GW is an 18 to 19 percent uplift on the April range ^[1], and roughly a quarter of everything the country currently draws at summer peak ^[2]. Added straight onto April's numbers, 2040 peak demand lands between 156.5 and 162.9 GW ^[3], which is 61 to 71 percent above the current summer peak ^[4]. The reactor comparison is also rounded up in the government's favour of drama: 18 units at 1.4 GW is 25.2 GW, and 24.7 GW is 17.6 units ^[5]. None of that yet includes electric vehicles, which the ministry says are spreading faster than expected, or the push to expand heat pumps ^[9].

The sequencing is the part operators should read closely. Power authorities will draw up the generation capacity plan from the demand figures presented at the hearing ^[10], and the renewable energy rollout plan through 2040 is unveiled the same day ^[2]. But how much of the non-renewable demand gets covered by new nuclear reactors is pushed to a separate debate around September or October ^[11], with the coal phase-out roadmap and electricity market reform each getting their own hearings later ^[12]. So the demand number is fixed first, the renewables number second, and the firm-capacity question that actually determines whether a fab gets energised is settled last. The plan is normally revised every two years, but the 11th plan was only finalised last year, a year later than scheduled, so the 12th is arriving in close succession ^[13]. The fourth debate is billed around the era of the "electricity state" ushered in by the AI revolution ^[14].

Three things to watch. First, whether the published 2040 figure is genuinely additive to April's range or whether the mega-project load is netted against existing assumptions. Second, the transmission and substation component, since the plan explicitly covers network build-out ^[3] and the 24.7 GW sits in specific clusters rather than across the country ^[7]. Third, the September-October nuclear session, which is where the gap between the new demand line and the renewables line has to be closed.