Efficiency Analysis of The Synchronous Condenser Operating Mode in Hydroelectric Power Plants in Terms of Water Use

Global climate change and the resulting water scarcity necessitate innovative and efficient approaches in the operation of hydroelectric power plants. Although active electricity generation may come to a halt as water levels drop to critical thresholds during drought periods, the potential of these facilities to contribute to grid stability through the synchronous condenser (SC) mode persists. In this study, the effects of operating the four electricity generation units at the Alpaslan-1 Hydroelectric Power Plant in SC mode on water usage and energy efficiency were analyzed experimentally. During the test process, the units were operated in SC mode for a total of 172 minutes; the facility drew 72 MVAr of reactive power from the grid without performing active electricity generation, thereby providing a total of 52.54 MVArh of reactive energy support to the system. By evaluating the 11-year hydrological data of the plant covering the years 2014-2024, drought periods were determined according to the long-term average, and the strategic advantages of operating the plant in SC mode during these times were demonstrated. According to the findings, a water saving of 575443.2 m³ was achieved in the reservoir thanks to this short-term operation of 172 minutes. It has been calculated that the approximately 115.4 MWh of energy that this saved water would generate if converted to active production would be sufficient to meet the annual electricity needs of 38 households. Furthermore, it was determined that 91.37 MVArh of reactive energy could be provided to the grid for every 1 hm³ of water retained in the reservoir due to the SC mode in drought years. These results demonstrate that hydroelectric power plants, even during periods of water scarcity, can act as strategic "reactive power centers" rather than remaining idle, thereby contributing highly efficiently to grid optimization and long-term sustainable water management.