South-east Europe’s power systems are facing a shortage of long-duration flexibility, even as battery storage is used to address short-term market volatility. Against that backdrop, pumped-storage hydropower projects including Đerdap 3, Čebren and Bistrica are again featuring in regional energy and trading discussions. The facilities are being discussed not only for grid-security purposes but also for their trading and portfolio-support potential.
Regional system vulnerability is linked to hydrological conditions, coal plant availability, import dependence and transmission constraints. Solar capacity is expanding across the region, but solar-dominated systems require storage beyond the midday-to-evening balancing window. Wind output can vary over several consecutive days, while dry years can increase reliance on imports.
Pumped hydropower in regional flexibility planning
In this operating environment, pumped-storage hydropower is described as providing a deeper flexibility layer than conventional lithium-ion battery systems. The discussion centers on aligning storage duration with multi-hour and multi-day needs in power markets. It also connects pumped storage with firming requirements for renewable generation portfolios during periods of weak output.
For trading desks, pumped-storage assets are associated with multiple revenue streams. They can buy electricity during low-price periods and sell during peak-price hours. They can also provide balancing services and hedge renewable generation underperformance.
Traders are also expected to use pumped-storage resources to support capacity adequacy requirements and to offer firming products for long-term PPAs. The asset characteristics cited include longer operational lifetimes and greater storage depth than most battery technologies currently deployed in the market. These features are tied to the ability to manage price spreads over extended timeframes.
Đerdap 3, Čebren and Bistrica project details
Serbia’s Đerdap 3 is described as the most strategically positioned project in the region. The proposed site is on the Danube upstream from Đerdap 1, with integration into one of the Balkans’ key hydroelectric corridors. Romania has been evaluating the project, and unofficial discussions have included possible participation by Hidroelectrica.
A storage facility at the Đerdap 3 location is described as having potential implications for power price spreads and trading opportunities among Serbia, Romania, Hungary and Bulgaria. North Macedonia’s Čebren is presented as significant within a smaller national market. Proposed capacity ranges from 333 MW to 458 MW, with annual generation estimated at 1–1.2 TWh.
The Čebren project is discussed as potentially shifting North Macedonia from a market primarily exposed to imports toward a provider of regional flexibility services. Serbia’s Bistrica project includes planned reversible turbine units, which would add to the region’s flexibility portfolio. Together, these projects are repeatedly referenced in regional trading discussions.
Permitting and financing constraints for pumped storage
The main obstacle highlighted for pumped-storage developments is financing and project execution. Such projects require complex permitting procedures and water-use approvals before construction can proceed. They also involve extensive civil engineering works.
The investment payback period is described as long, affecting project timelines and financing structures. Even so, the need for additional long-duration storage capacity is linked to limits that renewable expansion may face without it. For regional trading desks, pumped hydro is described as likely to become a valuable flexibility asset in the coming energy transition.