We examine the optimal role, or use case, for a space solar power system (SSPS) in an electrical grid by using a full year of historical load data from three U.S. cities in different climate regions to drive a simulation of load and supply. We include the impact of the eclipsing of the power station during each equinox season. SSPS operation through eclipse requires over-sizing the space power station relative to the load, and storing the difference in energy for use during the eclipse seasons. We found the optimal use case for SSPS in cities north (south) of the subtropic region is providing the base-load supply and that load chasing may be the optimal use case for cities in the sub-tropical and tropical regions. Further analysis is needed to confirm this latter result.