This paper introduces operation planning and capacity calculation through combining of short-duration and long-duration energy storage systems (ESSs) for reducing curtailment. Because curtailment is related to time, a photovoltaic (PV) output occurs, short-duration ESS has a limitation for reducing curtailment; and capacity of long-duration ESS can be overestimated. We show a combination of short-duration battery energy storage system (BESS) and long-duration pumped storage hydro (PSH) to reduce curtailment as minimizing capacity. A combination of BESS and PSH is applied to small-scale grids with a high penetration of variable renewable energy. To find the effect of an input order of two types of ESSs, several case studies are conducted, and results are compared when the short-duration and long-duration of ESS are combined. If PSH is put in first, curtailment can be further reduced with less capacity.