Issue Loss of grid inertia as renewables expand, and the grid-forming battery response

Summary

Where adequate complementary measures are missing, expanding renewables can deepen grid vulnerability. Conventional synchronous generators provide physical inertia that keeps frequency from swinging sharply after a disturbance, but inverter-based solar and wind resources do not provide it by default. The author compares this to water levels changing slowly in a wide tank but quickly in a narrow, shallow one, so a higher renewable share can reduce inertia and heighten sensitivity to shocks. Carbon neutrality comes closer while grid operation may become harder, which the author calls the structural dilemma of the electrification era. Grid-forming battery storage, which uses inverter control to support voltage and frequency and emulate inertia, is drawing attention, and Korea is pursuing such functions through its ESS central contract market and related rule changes. Establishing systematic specifications and an institutional framework to back adoption is presented as the next task.