Application of Pumped Hydroelectric Energy Storages for Improvement of Power System Flexibility

Besides many benefits deriving from the energy transition process, it is not uncommon for modern power systems to be faced with difficulties in their operation. The issues are dominantly related to the non-dispatchable nature of renewable energy sources (RES) and mismatching between electricity generation and load demand. As a consequence of a constant peak load growth, this problem is particularly pronounced during the daily peak hours. Therefore, it is of great importance to conduct all necessary activities within the system in order to preserve the system stability and continuity of operation. The typical solution to this problem lays in the use of gas power plants and diesel engine power plants. However, these units are characterized by high operating costs and they are not in compliance with modern environmental protection aspirations. Instead of expensive and outdated generation capacities, peak load shaving can be achieved through the engagement of pumped hydroelectric energy storage (PHES), and this is the primary focus of the paper. In addition to presenting the fundamental characteristics and operation principles of PHES, a new algorithm for peak shaving is developed. The traditional operation algorithms rely on complex optimization techniques and they are based solely on the day-ahead load forecast, meaning they don’t take into account the volatility of RES. The developed algorithm overcomes the aforementioned drawbacks of the existing algorithms and its validity is confirmed through performed simulations on the modified version of the IEEE 30 bus system.