Persistently weak Danube inflows are restricting output from Serbia’s Đerdap hydropower cascade and beginning to affect thermal generation at Kostolac, increasing the operational and financial pressure on state-owned utility EPS.
Current Danube inflows are running at approximately half the long-term average and are approaching the river’s biological minimum. Forecasts offer little indication of a material recovery during the coming weeks.
Đerdap 1 has recently generated slightly more than 5,000 MWh per day, around one-third of its normal production. That volume corresponds to an average output of only about 208 MW, compared with an implied normal level of roughly 625 MW. The lost production is therefore close to 10 GWh per day.
At wholesale prices of €100–130/MWh, replacing that missing energy could cost approximately €1–1.3 million per day, before accounting for congestion, balancing requirements and differences between hourly import prices. The financial impact grows rapidly when low hydrology coincides with evening scarcity or regional heat-driven demand.
EPS said all refurbished Đerdap units remain technically available and are operating at the maximum output permitted by current river conditions. The problem is therefore hydrological rather than mechanical, limiting the effectiveness of conventional availability improvements.
The recently modernised Bajina Bašta pumped-storage hydropower plant provides some relief. EPS can purchase electricity during low-priced solar hours, pump water into the upper reservoir and generate during more expensive evening periods. This reduces replacement-energy costs but cannot fully offset sustained losses from the much larger Đerdap cascade.
Low water levels are also restricting cooling capacity at the Kostolac thermal power plants, forcing reductions in generation. The simultaneous impact on hydro and coal assets creates a correlated risk: the same river conditions weaken two separate parts of EPS’s production portfolio.
Serbia’s electricity system remains operationally stable, but the economic burden is shifting toward imports, short-term trading and careful use of stored hydro resources. The Danube drought has become a balance-sheet issue as much as a generation constraint.
