SMR–renewable microgrids for 24/7 carbon-free energy matching in data centers: Techno-economic performance and sustainability indicators

Hyperscale data centers seeking round-the-clock carbon-free energy must balance investment cost with hourly supply adequacy. Prior studies identify small modular reactor (SMR) cost drivers and hourly-procurement effects but leave open how replacing reactor modules with renewables and storage changes cost, hourly adequacy, and infrastructure needs. This study jointly sizes up to eight 170-MW SMR modules, photovoltaic (PV), offshore wind, batteries, and converters for an off-grid Korean data-center load of 8.76 TWh/yr. Hourly HOMER simulations evaluate 24 technology-cost and financing cases, with fixed operating and decommissioning charges on installed SMR capacity. Seven-module hybrids are selected in 17 cases, using 332.8–395.6 MW PV and 0.842–1.043 GWh storage. Pooling compatible candidates changes three module counts and reduces net present cost (NPC) by at most 0.91%. An annual unmet-energy limit of 1 kWh, applied to the stored candidates, raises NPC by up to 4.34% and changes module count in eight cases. Re-optimization for the most adverse observed year replaces the renewable-only selection with seven modules. An independent Pyomo/HiGHS dispatch comparison for four fixed designs yields reconstructed NPC differences of −0.212% to +0.143%. Joint sizing links the marginal reactor module to cost, hourly adequacy, renewable overbuilding, storage turnover, land use, and nuclear fuel throughput.