LG Energy Solution, Samsung SDI and SK On are preparing to compete in South Korea’s third government-led Energy Storage System (ESS) central contract market auction, which could expand to around 1 gigawatt (GW). The Ministry of Climate, Energy and Environment and the Korea Power Exchange use the program to procure large-scale storage for grid operations, allowing selected operators to build ESS facilities nationwide and operate them as grid resources for 15 years. The exchange plans to issue the tender notice around the Chuseok holiday and has been inspecting its systems, although the final auction volume has not been set. The first two auctions covered 563 megawatts (MW) and 565MW. Samsung SDI took about 76% of the first auction, while SK On led the second with 50.3%; Samsung SDI won 35.7% and LG Energy Solution 14%. The third auction’s scale could be supported by the government’s 2028–2029 ESS deployment plan, semiconductor clusters, AI data centers and increasing renewable generation. Supply-chain stability and fire safety remain important non-price criteria, while falling bid prices could intensify competition. LG Energy Solution plans 1 gigawatt-hour (GWh) of initial domestic ESS-grade lithium iron phosphate (LFP) capacity at Ochang, SK On is converting Seosan lines for 3GWh, and Samsung SDI is stabilizing its domestic network. The companies are also expanding North American ESS production and order books as global shipments and demand rise, using domestic operating records to support overseas growth.