The main challenge associated with the integration of renewable energy sources lies in the mismatch between generation profiles and electricity demand. Addressing this issue within large-scale power systems leads to significant electricity price deviations on regional energy markets, as well as major variations in power flows across transmission networks, thereby increasing the risk of stability loss, interconnection outages, and even large-scale power system disturbances.

The spatial distribution of renewable energy sources enables the development of self-sustainable microgrids capable of locally balancing renewable generation and electricity consumption. This paper analyzes the operating conditions of microgrids integrating photovoltaic systems, wind power plants, and closed-loop pumped storage hydropower plants. A case study location will be used to present the construction conditions, layout configuration, and available storage capacity of a closed-loop pumped storage hydropower plant depending on the positioning of the upper and lower reservoirs. In addition, the impact of applying variable-speed machines on enhancing the operational flexibility of pumped storage hydropower plants will be examined.

Based on the available data regarding photovoltaic and wind power generation, as well as the consumption profile of the local distribution network, the possibilities for establishing a microgrid with a closed energy balance between generation and demand will be evaluated. Such a concept represents a prerequisite for conducting dynamic performance analyses and developing control structures capable of enabling the reliable operation of energy self-sustainable microgrids under real operating conditions.