Serbia’s deteriorating hydrology has turned two long-discussed pumped-storage projects into an immediate test of the country’s energy investment policy. RHPP Bistrica, planned at 661 MW, is not expected before 2032, while the much larger 1,800 MW Đerdap 3 remains at an earlier development stage and has a target completion date of 2036. Neither project has a fully closed financing structure.
The urgency is visible in the operating data. During the past three months, the Đerdap 1 hydropower plant reportedly generated at only around 20 per cent of its normal production level, while Đerdap 2 operated at approximately one-third of capacity. Energy Minister Dubravka Đedović Handanović described Đerdap’s production as the lowest recorded, although the government has continued to maintain that Serbia’s electricity supply remains stable.
Both statements can be true in a narrow technical sense. The power system can remain physically stable while facing a severe economic imbalance, provided that Elektroprivreda Srbije, or EPS, imports enough electricity, keeps its lignite plants available and uses its remaining hydro reserves selectively. Stability does not mean that the system is operating cheaply or without risk.
On 4 August, Serbian electricity consumption was forecast at an average 4,030 MW, against domestic generation of approximately 3,534 MW. That left an average import requirement of 496 MW, widening to nearly 797 MW during peak hours. Coal supplied approximately 79 per cent of Serbia’s reported generation mix on the preceding day, while hydro output averaged only 621 MW and wind contributed about 110 MW.
The financial exposure was equally clear. The SEEPEX day-ahead baseload price reached €174.64/MWh, with an evening maximum of €496.80/MWh at H20. Serbia traded at a baseload discount to Hungary, Romania, Croatia and Slovenia, but that average concealed a sharp evening scarcity premium. Imports procured during those hours are materially more expensive than the baseload price suggests.
The drought has strengthened the case for storage, but neither Bistrica nor Đerdap 3 can provide relief during the present hydrological cycle. Serbia is therefore paying for the gap between recognising the need for system flexibility and delivering the infrastructure capable of supplying it.
Bistrica remains short of financial close
The proposed RHPP Bistrica is the more advanced of the two projects. It is planned with four reversible generating units and combined installed capacity of 661 MW. Expected annual electricity output has been stated at approximately 1,600 GWh.
The government’s energy-infrastructure development plan estimates the investment at €962.5 million, although more recent public figures have reached approximately €1.2 billion. The implied capital cost has therefore moved from around €1.46 million per MW to as much as €1.82 million per MW.
That range is credible for a large pumped-storage project only if it includes a carefully defined scope covering underground works, reservoirs, waterways, turbines, generators, grid connection, access infrastructure, environmental mitigation, land acquisition, financing costs and contingencies. A headline CAPEX number without a stable technical baseline can move substantially once geological risk and construction interfaces are priced.
Serbia has been discussing financing with the Japan International Cooperation Agency, or JICA. The latest timetable envisages a formal financing agreement being signed during EXPO 2027. Japanese banks and the selected delivery structure are expected to provide the funding, but the amount, tenor, sovereign support and allocation of construction risk have not yet been publicly fixed.
A ceremonial signing in 2027 would not itself represent financial close. Before debt can be drawn, the project will require an agreed feasibility case, environmental and social approvals, a bankable EPC structure, confirmed grid arrangements, land availability, cost verification and a complete conditions-precedent package.
The government’s current target is to complete Bistrica by 2032, with construction expected to begin in 2027. That implies a construction period of roughly five years. Such a programme is ambitious but not impossible for a project entering construction with mature design, completed expropriation, secured financing and thoroughly investigated geological conditions.
Bistrica has not yet reached that position. Existing documentation reportedly includes a preliminary feasibility study and main design, while the construction permit is expected during 2026. Discussions with landowners have only recently begun in the municipalities of Priboj and Nova Varoš, where land must be acquired for preparatory and permanent works.
Expropriation is not an administrative detail. Pumped-storage plants require reservoirs, water-transfer infrastructure, tunnels, shafts, access roads, transmission facilities and construction compounds. Delays in obtaining land can prevent contractors from opening work fronts even when financing and major equipment contracts are ready.
Environmental and water-management approvals are equally important. The project must demonstrate acceptable impacts on river systems, biodiversity, communities, landscape, water users and sediment management. These issues must be resolved before the main construction programme begins because design changes introduced after excavation starts are costly and difficult to finance.
The 2032 target therefore depends on several development streams moving in parallel during 2026 and 2027. A delay of 12-18 months in permitting, financing or land acquisition would probably move commercial operation into 2033 or 2034, while increasing capitalised interest, owner’s costs and contractor escalation.
At a project cost of approximately €1.2 billion, even a one-year delay could add tens of millions of euros through financing charges, inflation, extended project management and remobilisation. The greater cost would come from leaving Serbia exposed to several additional summers and winters without the planned storage capacity.
Pumped storage changes when Serbia buys electricity
Bistrica is often described as a new source of electricity production, but pumped storage does not create primary energy. It uses electricity to pump water into an upper reservoir and later recovers part of that energy by releasing the water through turbines.
Because pumping and generation involve losses, the plant consumes more electricity than it returns. Its value comes from changing the timing of energy: buying or absorbing electricity when prices are low and supplying it during periods of high demand, limited renewable production or system stress.
That role is becoming increasingly valuable in Serbia. Solar capacity across the region is creating lower prices around midday, while the highest prices increasingly occur after sunset. On 4 August, SEEPEX fell to approximately €70/MWh at H13 before rising to almost €497/MWh at H20. The theoretical hourly spread exceeded €426/MWh.
A pumped-storage plant cannot capture that entire spread after accounting for pumping losses, transmission charges, market liquidity and operational constraints. It can nevertheless earn revenues from several sources: day-ahead arbitrage, intraday trading, balancing energy, frequency services, reserve capacity, congestion management and emergency system support.
Bistrica’s 661 MW would be large enough to change Serbia’s evening balance materially. Compared with the 797 MW peak import requirement recorded on 4 August, the plant could theoretically cover most of the deficit for a limited number of hours, subject to the available stored water and transmission conditions.
Its bankability should therefore not be assessed only through annual generation of 1,600 GWh. The financial model needs separate revenue assumptions for pumping costs, generation prices, balancing services, reserve payments and avoided import expenditure. It also needs conservative scenarios for hydrology, renewable build-out, market coupling and the future performance of Serbia’s coal fleet.
The rehabilitation of the existing Bajina Bašta pumped-storage plant has already demonstrated the operational logic. It can pump during lower-price periods and generate during morning and evening peaks. But one existing storage asset is insufficient for a system that is adding variable renewables while relying on ageing lignite generation and facing deteriorating summer hydrology.
Đerdap 3 remains a development project rather than a construction project
The proposed RHPP Đerdap 3 is much larger. The current concept envisages six reversible units with total installed capacity of 1,800 MW. The estimated investment is €2.63 billion, equivalent to approximately €1.46 million per MW.
The project is targeted for completion in 2036, placing it at least a decade away under the official schedule. The financial structure has not been closed, and the required funding has not been secured.
The Ministry of Mining and Energy launched an expression-of-interest process restricted to US companies under the Serbia-US energy cooperation framework. Six companies reportedly responded, but Bechtel was the only participant to submit a compliant offer and qualified for the second phase.
Bechtel had previously prepared preliminary work connected with the project and has shown interest in Đerdap 3 since 2022. The company is therefore positioned as the probable strategic delivery partner, although the government working group has no published deadline for completing the selection process.
The contracting route is unusual because the potential construction partner is being selected outside the standard public-procurement procedure, while a separate competitive procurement has been launched for planning and part of the technical documentation.
That documentation package is expected to include the general design, preliminary feasibility study, strategic environmental assessment and other development documents. This confirms that Đerdap 3 remains in a relatively early project-definition phase. The final layout, geological conditions, reservoir arrangement, grid interfaces, environmental restrictions and construction schedule must still be converted into an investable technical baseline.
The current estimate of €2.63 billion should therefore be treated as a planning value rather than a fixed construction price. For an underground pumped-storage project of this scale, geological uncertainty can materially affect tunnelling costs, excavation methods, support systems, water sealing and programme duration.
The project will also require major transmission-system integration. An 1,800 MW plant is not simply another generating facility connected to the existing network. It is both a very large consumer during pumping and a very large generator during discharge.
The grid must be capable of absorbing the pumping load without creating congestion and exporting the full generating output without destabilising the system. That requires detailed load-flow, short-circuit, dynamic-stability, frequency-response and N-1 security studies. Associated substations and high-voltage lines could require several years of separate development and construction.
Serbia’s transmission network is already facing congestion and connection constraints. The timetable for Đerdap 3 must consequently include not only the power plant but also the grid investments needed to make its 1,800 MW technically usable. A storage facility completed ahead of its transmission infrastructure would become a partially stranded asset.
A combined investment envelope above €3.8 billion
Using the higher Bistrica estimate, the two projects represent a combined investment of approximately €3.83 billion. Applying development contingencies, grid reinforcement, owner’s costs and financing during construction could move the effective programme envelope above €4 billion.
This scale requires a financing strategy that extends beyond contractor-led credit. Serbia must determine which risks remain with the state, which are transferred to EPS, which can be allocated to contractors and which can be accepted by lenders.
Hydrological and market risks cannot simply be passed to an EPC contractor. Construction and performance risks can be allocated through contractual guarantees, but long-term revenue depends on market spreads, balancing rules, renewable penetration and the operating strategy adopted by EPS or another project company.
A state-supported structure could secure cheaper debt but would add contingent liabilities to the sovereign balance sheet. A project-finance structure would require predictable revenues, potentially through availability payments, regulated storage remuneration, capacity payments or long-term contracts for ancillary services.
Pure merchant financing would be difficult for investments of this size. Day-ahead arbitrage can be lucrative during scarcity events, but the revenue is volatile and may decline as competing batteries, interconnections and flexible demand enter the market. Lenders will require a dependable contracted revenue floor.
The projects also need to be evaluated together. Completing Bistrica in the early 2030s would materially increase flexibility, while Đerdap 3 would transform Serbia into one of the largest storage hubs in Southeast Europe. Their operational strategies, grid requirements and market revenues could overlap, particularly during the same low-price and high-price hours.
A portfolio model should therefore examine both projects against Serbia’s planned solar, wind, battery and interconnection pipeline. Bistrica’s economics cannot be based on current price spreads alone, while Đerdap 3 should not assume that scarcity conditions observed in 2026 will remain unchanged through the 2040s.
The present crisis will be managed without either project
The immediate hydrological shortage will have to be covered through Serbia’s existing system. That means greater dependence on lignite production, selective use of hydro reserves, operation of the rehabilitated Bajina Bašta storage plant, electricity imports and possible demand-management measures during the tightest hours.
Regional availability cannot be taken for granted. Romania is protecting the remaining operating unit at the Cernavoda nuclear plant against extremely low Danube flows. Hungary has faced reduced nuclear availability, while Croatia is importing close to half of its summer electricity requirement. Serbia has recently relied heavily on flows from Bulgaria and North Macedonia.
The country’s exposure is therefore not simply the cost of imported electricity. It is the risk that neighbouring systems will need the same energy at the same time. The evening price spikes approaching €500/MWh demonstrate the financial consequence when flexible supply and transmission capacity become scarce simultaneously.
Bistrica and Đerdap 3 could reduce that exposure, but their value will depend on disciplined project preparation rather than political timetable announcements. Bistrica still needs a closed financing package, completed land acquisition, permits and a construction-ready design. Đerdap 3 requires a bankable technical concept, strategic-partner decision, environmental pathway, grid programme and financing model.
Serbia’s hydrological crisis has arrived in 2026. The first major new pumped-storage capacity is scheduled no earlier than 2032, and the second not before 2036. The six-to-ten-year gap between present system stress and future storage capacity has become the central fact of the country’s electricity-security strategy.
