Fortis Energy’s planned solar and battery storage platform in northern Serbia is advancing at a time when the country’s electricity market is undergoing a structural transition, with tightening supply margins, increasing price volatility and growing exposure to carbon-driven price formation across interconnected European markets.
Located near Sremska Mitrovica, the project is being developed as a hybrid system combining up to 270 MW of solar capacity with battery storage scaling to approximately 72 MWh, alongside an initial phase of 90 MW solar paired with 36 MWh of storage. With a secured grid connection of around 180 MW AC, the project is positioned to operate directly within Serbia’s balancing and day-ahead market framework while maintaining optionality for cross-border trading.
Serbian market shifts toward tighter fundamentals
Serbia’s electricity system, historically dominated by lignite generation from EPS, is entering a more constrained operating environment. Ageing thermal capacity, periodic outages and hydrological variability have reduced system flexibility, while demand has stabilised at elevated levels of approximately 32–35 TWh annually.
At the same time, wholesale price formation is increasingly influenced by neighbouring EU markets through interconnections with Hungary, Romania, Bulgaria and Croatia. Day-ahead prices on SEEPEX have frequently tracked Central European benchmarks, with baseload levels fluctuating between €80/MWh and €130/MWh in recent months, and peak periods exceeding €150/MWh during winter demand spikes.
This growing price coupling is occurring in parallel with rising volatility. Intraday spreads in Serbia and the wider region are now regularly reaching €30–70/MWh, driven by intermittent renewable output in surrounding EU systems and constrained dispatch flexibility domestically.
Hybrid assets gain importance in dispatch structure
Within this evolving system, hybrid solar-plus-storage assets are beginning to play a more central role in balancing supply and demand.
The Fortis project’s battery component is expected to enable:
- Intraday arbitrage across SEEPEX and neighbouring markets
- Peak shifting from midday solar generation to evening demand periods
- Participation in ancillary and balancing services as Serbia expands its flexibility markets
This is particularly relevant in northern Serbia, where solar capacity additions are accelerating and grid congestion is becoming more pronounced during high-generation hours.
Without storage, solar output risks increasing curtailment exposure. With storage, the same output can be reshaped into a more dispatchable profile, improving system integration and revenue stability.
Carbon pricing indirectly reshaping Serbian price formation
Although Serbia does not yet operate a full EU ETS-equivalent carbon pricing system, the impact of carbon costs is increasingly reflected in domestic prices through market coupling.
EU ETS prices in the range of €70–90/tCO₂ are adding an estimated €55–85/MWh to thermal generation costs in neighbouring EU markets. As Serbia imports and exports electricity across these borders, these carbon-adjusted prices are increasingly influencing SEEPEX price formation.
This creates a dual dynamic:
- Domestic lignite generation remains relatively low-cost at €50–60/MWh
- Imported or EU-linked prices reflect higher carbon-adjusted levels, often exceeding €100–130/MWh
The result is a widening spread between production cost and market price, reinforcing the value of low-marginal-cost renewable generation.
Revenue optimisation linked to market volatility
The Fortis project is expected to generate over 365 GWh annually, placing it among the larger renewable contributors in Serbia’s evolving generation mix.
At current baseload price levels of €80–120/MWh, this implies annual revenue potential of €30–45 million, with upside in periods of tight supply.
However, a growing share of value is expected to come from short-term market dynamics rather than baseload production alone.
Battery storage allows the project to capture:
- Intraday price spreads frequently reaching €50–100/MWh
- Price spikes during evening peaks or system stress events
- Balancing market opportunities as flexibility demand increases
This aligns the asset more closely with a trading-oriented revenue model, rather than a purely generation-based one.
Grid constraints and curtailment risk remain key variables
Serbia’s transmission system, operated by EMS, is facing increasing pressure from renewable integration, particularly in Vojvodina where multiple solar and wind projects are under development.
Curtailment risk is becoming a central consideration for new projects. During periods of high solar output and limited export capacity, generation may need to be reduced to maintain system stability.
The Fortis project mitigates this risk through:
- Integrated battery storage, enabling output shifting
- Strategic location near key transmission corridors
- Secured grid connection capacity of 180 MW AC
Even so, delays in grid reinforcement or interconnection expansion could impact project performance. A 12–18 month delay in grid upgrades could reduce equity returns by 2–4 percentage points, according to market estimates.
Investment case supported by structural market change
The total investment envelope for the project is estimated at €220–285 million, including solar generation, storage systems and grid infrastructure.
Debt financing is expected to cover 65–75% of CAPEX, supported by interest from international lenders attracted by Serbia’s growing renewable pipeline and the project’s hybrid design.
Equity returns are projected in the range of:
- 10–13% IRR (base case)
- 14–18% IRR (upside, driven by volatility and trading gains)
- 8–10% IRR (downside, under higher curtailment or price compression)
The inclusion of storage is a key factor in maintaining returns under variable market conditions.
Role within Serbia’s evolving power mix
The Fortis project reflects a broader shift in Serbia’s electricity system, where new capacity additions are increasingly renewable and market-linked.
Coal remains dominant, but its role is gradually being challenged by:
- Rising maintenance costs and operational constraints
- Increasing alignment with EU carbon pricing mechanisms
- Growing penetration of wind and solar capacity
In this context, hybrid renewable assets are emerging as a bridge between legacy baseload generation and a more flexible, market-driven system.
Transition toward a volatility-driven market
Serbia’s electricity market is moving toward a structure where price formation is shaped by:
- Cross-border carbon-adjusted pricing
- Renewable intermittency
- Short-term trading dynamics
In this environment, value is shifting from pure generation to flexibility, timing and market access.
The Fortis solar-plus-storage platform is positioned within this transition, combining low-cost renewable generation with the ability to respond to price signals in real time.
As carbon pricing continues to influence regional markets and grid constraints tighten, such hybrid assets are likely to play an increasingly central role in both system balancing and investment strategies across Southeast Europe.
