The latest special issue of HYDROLINK (2/2025), published by the International Association for Hydro-Environment Engineering and Research (IAHR), sheds light on the vital and evolving role of pumped storage hydropower (PSH) in global energy systems. Over the past fifty years, PSH has expanded significantly—initially serving as a solution to store surplus energy from thermal and nuclear plants during low-demand periods, and more recently, as a flexible backup to address the intermittency of wind and solar generation.

Several experts from the ETIP HYDROPOWER Forum contributed their insights and research to this special edition, emphasizing PSH’s critical role in supporting a secure and sustainable energy transition:

• Pumped Storage Hydropower in Arid Climates: A Crucial Asset for Energy Transition. Benoît Houdant and Thomas Pinchard (EDF) explore how PSH projects in water-scarce regions can enhance grid stability while contributing to renewable integration. Read more. 
• Design Challenges in the Renaissance of Pumped-Storage Hydropower to Support the Energy Transition. Anton Schleiss (ETIP HYDROPOWER, EPFL) examines the engineering and environmental challenges driving modern PSH development. Read more.
• The Critical Role of Power Intake/Outlet Structures in Pumped Storage Schemes: Design Challenges and Optimization. Azin Amini and Giovanni De Cesare (EPFL) highlight the significance of hydraulic structures in optimizing PSH scheme efficiency and reliability. Read more.
• Pumped-Storage Technology: Fixed vs. Variable Speed. Michael Schmid (Andritz) analyzes the benefits and limitations of fixed and variable speed technologies in modern PSH plants. Read more.

This special issue underscores the strategic importance of pumped storage hydropower as a cornerstone technology for a decarbonized and resilient energy future. Access the full issue at HYDROLINK 2/2025.