Đerdap 3 is proposed as a pumped-storage project on the Serbian side of the Danube River, upstream of the existing Đerdap 1 complex. The location would place the project between Serbia and Romania while remaining relevant to Hungary, Bulgaria and the wider south-east European trading region. The concept links geographical positioning with cross-border relevance and flexibility for power markets.
The existing Danube hydro system already operates at scale. Đerdap 1 provides approximately 2,300 MW of installed capacity, while Đerdap 2 contributes another 520 MW. A third facility would add more than generation capacity by introducing energy-storage capability.
The storage function described for Đerdap 3 would allow electricity to be absorbed during low-price periods and released during high-value market windows. The project is framed as long-duration flexibility that becomes more important as solar and wind penetration increases across the region. The stated aim is to support system stability and trading efficiency.
Romanian review and potential Hidroelectrica involvement
Romanian authorities are evaluating the project, with the assessment covering economic viability, environmental impact and implications for the regional power system. The review in Bucharest is described as carrying commercial and strategic significance for the wider regional context. The process also depends on information provided by Serbia.
Hidroelectrica has been discussed as a potential participant with a 50% ownership stake. The discussion is linked to Serbia providing the necessary project information to Romanian counterparts. If Romanian involvement proceeds, it would shift Đerdap 3 from a national infrastructure initiative toward a regional energy platform.
The expected effect of participation would be tied to market integration, investment confidence and cross-border cooperation. The project’s role in those areas is presented as dependent on how Romanian evaluation develops. Cross-border positioning remains central to how the project is described in relation to regional power flows.
Trading revenue mechanisms and cross-border price spreads
The revenue model for Đerdap 3 is described through price spread opportunities across Serbia, Romania and neighbouring markets. Charging would occur during periods of depressed prices, including times when solar generation peaks or demand weakens. Discharging would be aligned with evening peaks, winter scarcity events and periods of higher export demand.
The ability to capture cross-border arbitrage is said to depend on market design and transmission availability. Under those conditions, the facility could monetise price spreads across multiple interconnected markets. The description ties operational timing to regional price differentials rather than generation-only dispatch.
Đerdap 3 is also positioned as an asset that could interact with export demand patterns. Its pumped-storage operation would support shifting electricity from low-price periods to higher-value windows. That linkage is presented as relevant across interconnected markets in south-east Europe.
Pumped storage support for renewable PPAs
The project is also described as relevant to renewable power purchase agreements (PPAs). Serbia’s wind and solar sector is characterised as requiring firming solutions to reduce merchant risk. It is also linked to mitigating curtailment exposure and improving revenue predictability.
Pumped storage is presented as capable of providing structured flexibility products for industrial consumers, utilities and energy traders. The stated purpose is to make renewable generation more attractive by offering reliable low-carbon electricity supply. The role in PPAs is framed around improving contracting outcomes for variable renewables.
Key constraints: execution, water governance and financing
The main challenges identified are project execution, bilateral water governance and long-term financing. Romanian support is described as unlikely if development could negatively affect generation at existing Danube facilities. That condition places emphasis on environmental assessments within the approval process.
The approval pathway is described as requiring environmental assessments and hydrological modelling. Bilateral water governance is highlighted as part of the constraints affecting how approvals could proceed between countries involved in the Danube basin. Long-term financing remains another gating factor for delivery.
The underlying commercial rationale for Đerdap 3 is described as strengthening despite these constraints. If realised, it would be positioned as transforming the Danube from a traditional generation corridor into a regional storage, flexibility and electricity-trading hub. The change would be expected to affect power-market dynamics across south-east Europe.