Renewable energy sources (RES) are the key element of sustainable energy systems. To accommodate the intermittency of wind (and solar) electricity generation, energy storage is critical. The aim of the study was to evaluate the potential of wind energy storage in the existing hydropower plant reservoirs in Latvia with the pumped hydroelectric energy storage (PHES) technology, considering the current and projected future wind energy capacities. An algorithm was developed and used for data aggregation and analysis, calculations, and forecasting. The three River Daugava hydroelectric power plants are the largest electricity producers in Latvia, and their generation capacity depends on seasonal variations. Currently, Latvia's electricity generation from RES is the highest during the spring season when maximum hydropower potential is utilized. However, wind energy has a potential to grow and could supplement hydropower throughout the year. Decreasing the existing administrative procedure heaviness to faster achieve the climate neutrality targets and energy autonomy by increasing RES development in Latvia is a way to create sustainable energy production. A rational future scenario in Latvia is to expand wind parks and integrate pumped hydroelectric energy storage systems in the existing cascade hydropower plants.