Assessing Hydrodynamic and Operational Efficiency of a Solar-Driven Pumped Hydropower System under Changing Weather Conditions: A Case Study in Lake Velence Catchment, Hungary

Abstract:

Solar photovoltaic systems are the most dynamically expanding renewable energy technology, their capacities have doubled globally over the last two years. The transition to solar energy offers numerous advantages, it poses significant challenges for the electricity grid stability. These systems have high production fluctuation within the day and vast overproduction in peak hours. To improve stability, economic operation and efficiency of electricity network, both fluctuation balancing and excess energy storage are essential. Presently two technologies are mostly used: battery-based and pumped hydropower energy storage systems. This study focuses on evaluating the operating efficiency of solar-driven pumped hydropower energy storage system in the catchment of Lake Velence under changing weather conditions. Lake Velence has been struggling with severe drought problems for years, posing challenges to water experts, and making fair water distribution difficult for water users. The nearby northern hilly region of the lake provides suitable location for municipal-scale pumped hydropower developments in terms of social, techno-economic and topographical conditions. Furthermore, due to scarce water resources, inefficient operation could cause additional tension among water users, therefore, detailed evaluation of system efficiency is required, along with life-cycle economic analysis and hydrodynamic optimization of reservoirs and pipelines. Using potential reservoir locations identified in a case study from 2025 for pumped hydropower energy storage, together with meteorological data, we analyze and optimize in a self-developed Matlab model 1) the hydrodynamics of the system and 2) evaporation losses of reservoirs, on a daily basis over years, under changing weather conditions. Hydrological evaporation and hydrodynamic friction losses, together with possible interventions to reduce their negative effects, were assessed with life-cycle cost analysis to present environmental-social and economic benefits. Changing weather conditions have significant impact on operational efficiency and can negatively affect water requirements that raise conflicts among water users. The solely solar-driven pumped hydropower systems are spreading but still in their early stages of development. Long-term and extended data on their operation is still limited and their performance under changing weather conditions requires further research. This research investigates hydrodynamic and hydraulic operation efficiency and couples with economic life-cycle cost analysis, supporting guidance for optimization and evaluation of future developments.

• Periodical: Advances in Science and Technology (Volume 181)
• Pages: 365-377
• DOI: https://doi.org/10.4028/p-iM7vA5
• Online since: August 2026
• Authors: Attila Kálmán*, Katalin Bene
• Keywords: Carbon Footprint, Green Energy, Pumped Hydropower, Sustainability, Water Scarcity

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