Serbia 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 tender is run by Serbia’s Ministry of Mining and Energy. The assignment covers general design, a preliminary feasibility study, a special-purpose spatial plan and a strategic environmental assessment. Bids are due by 20 August 2026.
The scope of work is intended to produce documentation that will determine whether one of Serbia’s largest proposed energy investments can progress into detailed development. The project remains at an early stage, with current concepts defining a range of installed capacity from 1,200 MW to 2,400 MW. The elevation difference under consideration is approximately 400 metres.
Design parameters and potential reservoir sites
The concept uses the existing Đerdap 1 reservoir on the Danube as the lower reservoir. For the upper reservoir, the current options under consideration are Pešča or Brodica on the Severni Kučaj mountain. The location proposed for the scheme is in the Đerdap Gorge between Golubac and Donji Milanovac. It is described as approximately 65 kilometres upstream of Đerdap 1.
The planned infrastructure includes intake and outlet structures on the Danube. The design also calls for reversible pump-turbine units, tunnels and pressure pipelines. An upper-reservoir dam is included in the concept, alongside substations and switchgear. A high-capacity transmission connection would be required for grid integration.
Role in power balancing and market cycle shifting
At the upper end of the capacity range, Đerdap 3 is described as potentially becoming one of the largest flexibility assets in south-east Europe. The project would absorb electricity during periods of low prices or renewable surplus and return power during peak demand. It is positioned to provide balancing, reserve capacity and system restoration services.
The economic case has been linked to additions of wind and solar across Serbia and neighbouring markets. Midday prices are described as increasingly exposed to solar cannibalisation, while evening prices are said to remain supported by thermal generation and imports. Pumped storage is described as able to move large volumes of electricity across this daily price cycle more effectively than short-duration batteries, subject to sufficient storage hours at the reservoir.
Early-stage cost range and cross-border studies
The project’s preliminary capital envelope for a technically complex scheme covering 1.2–2.4 GW is described as ranging from approximately €2 billion to more than €6 billion. The range depends on final capacity, geology, tunnel length, reservoir design and environmental mitigation measures. The documentation contract is intended to narrow that uncertainty and identify a realistic configuration.
Cross-border coordination is identified as essential because Đerdap 3 would interact with the existing Serbia-Romania hydropower and navigation system. Studies are required to examine changes in river flows, navigation conditions and the operation of Đerdap 1 and Đerdap 2. Serbian authorities would need to coordinate technical assumptions with Romania as part of this work.
Environmental assessment within Đerdap National Park
The strategic environmental assessment is described as necessary because the project lies within Đerdap National Park. The assessment must address protected habitats, cultural assets, landscape effects, construction spoil, water regimes and the footprint of the upper reservoir. Environmental constraints could influence which upper-reservoir option—Pešča or Brodica—is selected.
The documentation also needs to support a defined revenue model for bankability. Energy arbitrage alone is described as potentially insufficient for multibillion-euro investment levels. Capacity remuneration, ancillary services, strategic-reserve payments or regulated cost recovery are cited as possible mechanisms to provide predictable cash flow.
The tender process is described as moving Đerdap 3 from a long-discussed concept towards structured project development. Key outputs are expected to include preferred capacity, reservoir location, environmental pathway, connection design and commercial framework capable of supporting long-term financing.
