Serbia’s Ministry of Mining and Energy has launched a procurement procedure worth approximately €5.3 million for planning and technical documentation for the proposed Đerdap 3 pumped-storage hydropower plant.
The assignment covers the general design, preliminary feasibility study, special-purpose spatial plan and strategic environmental assessment. Bids are due by 20 August 2026. The resulting documentation will determine whether one of Serbia’s largest proposed energy investments can move into detailed development.
Current concepts envisage installed capacity between 1,200 MW and 2,400 MW, with an elevation difference of approximately 400 metres. The existing Đerdap 1 reservoir on the Danube would serve as the lower reservoir, while the upper reservoir is being considered at either Pešča or Brodica on the Severni Kučaj mountain.
The project would require intake and outlet structures on the Danube, reversible pump-turbine units, tunnels, pressure pipelines, an upper-reservoir dam, substations, switchgear and a high-capacity transmission connection. Its proposed location lies in the Đerdap Gorge between Golubac and Donji Milanovac, approximately 65 kilometres upstream of Đerdap 1.
At the upper end of the capacity range, Đerdap 3 could become one of the largest flexibility assets in south-east Europe. It would absorb electricity during periods of low prices or renewable surplus and return power during peak demand, providing balancing, reserve capacity and system restoration services.
The economic case has strengthened as Serbia and neighbouring markets add wind and solar. Midday prices are increasingly exposed to solar cannibalisation, while evening prices remain supported by thermal generation and imports. Pumped storage can transfer large volumes of electricity across this daily price cycle more effectively than short-duration batteries, provided the reservoir offers sufficient storage hours.
The project remains at a very early stage. A broad preliminary capital envelope for a technically complex 1.2–2.4 GW pumped-storage scheme could extend from approximately €2 billion to more than €6 billion, depending on final capacity, geology, tunnel length, reservoir design and environmental mitigation. The €5.3 million documentation contract is intended to narrow that range and identify a realistic configuration.
Cross-border coordination will be essential. Đerdap 3 would interact with the existing Serbia-Romania hydropower and navigation system. Studies must examine changes in river flows, navigation conditions and the operation of Đerdap 1 and Đerdap 2, while the Serbian authorities will need to coordinate technical assumptions with Romania.
Environmental sensitivity is equally important because the project lies within Đerdap National Park. The strategic assessment must address protected habitats, cultural assets, landscape effects, construction spoil, water regimes and the footprint of the upper reservoir. Environmental constraints could materially influence the choice between Pešča and Brodica.
The project’s bankability will depend on a defined revenue model. Energy arbitrage alone may not support multibillion-euro investment. Capacity remuneration, ancillary services, strategic-reserve payments or regulated cost recovery may be needed to provide predictable cash flow.
The tender moves Đerdap 3 from a long-discussed concept towards structured project development. The decisive outputs will be the preferred capacity, reservoir location, environmental pathway, connection design and commercial framework capable of supporting long-term financing.
