The large-scale integration of renewable energy into modern power grids has led to a critical reduction in both system-wide rotational inertia and localized system strength. While previous studies have often analyzed these two factors in isolation, this paper observes their interdependent relationship. Specifically, this paper demonstrates the impact of short-circuit capacity (SCC) on system reserve requirements by quantifying the Frequency Regulating Reserve (FRR) volume necessary to satisfy frequency nadir criteria under the most severe contingency. This quantification is based on a comparative analysis of regional renewable energy deployment in the Korean power system. The simulation results reveal that the required FRR increases significantly when renewables are deployed in areas with low SCC. These findings highlight the potential hidden costs of interconnecting renewables in a weak grid area, particularly from the perspective of system inertia, underscoring the necessity of considering location-aware markets in future power systems.