Fortis Energy is advancing a significant solar and battery storage project near Sremska Mitrovica in northern Serbia, coinciding with a pivotal transition in the country’s electricity market. This shift is characterized by tightening supply margins, heightened price volatility, and an increasing influence of carbon-driven pricing mechanisms across interconnected European markets.
The hybrid system will integrate up to 270 MW of solar capacity with approximately 72 MWh of battery storage, beginning with an initial phase of 90 MW solar paired with 36 MWh of storage. The project has secured a grid connection capacity of around 180 MW AC, enabling it to participate directly in Serbia’s balancing and day-ahead market while also allowing for cross-border trading opportunities.
Historically reliant on lignite generation from Elektroprivreda Srbije (EPS), Serbia’s electricity system is facing constraints due to aging thermal infrastructure, intermittent outages, and hydrological variability. Demand remains stable at approximately 32–35 TWh annually, yet the wholesale price landscape is increasingly shaped by neighboring EU markets through interconnections with Hungary, Romania, Bulgaria, and Croatia. Recent trends show day-ahead prices on the South East European Power Exchange (SEEPEX) fluctuating between €80/MWh and €130/MWh, with peak prices surpassing €150/MWh during winter demand spikes.
This evolving price environment is marked by rising volatility, as intraday spreads in Serbia frequently reach €30–70/MWh. This volatility is largely driven by the intermittent nature of renewable energy sources in the region and limited domestic dispatch flexibility.
In this context, hybrid solar-plus-storage assets like Fortis’s project are becoming increasingly vital for balancing supply and demand. The battery component will facilitate intraday arbitrage across SEEPEX and neighboring markets, allow for peak shifting from midday solar generation to evening demand periods, and enable participation in ancillary services as Serbia enhances its flexibility markets.
As solar capacity expands rapidly in northern Serbia, grid congestion during high-generation hours presents a challenge. Without adequate storage solutions, solar output faces increased curtailment risks. However, integrating battery storage allows for a more dispatchable output profile, enhancing system stability and revenue predictability.
Carbon pricing is also playing a role in reshaping Serbian electricity pricing dynamics. While Serbia does not currently operate a full EU Emissions Trading System (ETS), carbon costs are increasingly reflected in domestic prices due to market coupling with EU neighbors. Current EU ETS prices range from €70–90 per ton of CO₂, which adds approximately €55–85/MWh to thermal generation costs in surrounding markets. Consequently, imported electricity often reflects higher carbon-adjusted prices exceeding €100–130/MWh.
This creates a widening gap between domestic lignite generation costs (approximately €50–60/MWh) and imported prices, underscoring the competitive advantage of low-marginal-cost renewable energy sources like those offered by Fortis’s project.
Projected to generate over 365 GWh annually, the Fortis project positions itself as a major contributor to Serbia’s renewable energy mix. With current baseload price levels estimated between €80–120/MWh, annual revenue potential could reach between €30 million and €45 million, particularly during periods of tight supply. However, much of this value will likely stem from short-term market dynamics rather than solely from baseload production.
The integration of battery storage will enable the project to capitalize on intraday price spreads that can reach €50–100/MWh and capture price spikes during peak demand or system stress events. This strategic positioning aligns the asset more closely with a trading-oriented revenue model rather than relying exclusively on generation-based income.
Despite these advantages, challenges remain regarding grid constraints and curtailment risks. The transmission system operated by EMS faces mounting pressure from renewable integrations, particularly in Vojvodina where multiple solar and wind projects are being developed. During periods of high solar output combined with limited export capacity, curtailment may be necessary to maintain system stability.
The Fortis project seeks to mitigate these risks through its integrated battery storage solution and strategic location near key transmission corridors. However, potential delays in grid reinforcement or interconnection expansion could adversely affect project performance; estimates suggest that a delay of 12–18 months could reduce equity returns by 2–4 percentage points.
The total investment required for this initiative is estimated between €220 million and €285 million, covering solar generation capabilities, storage systems, and necessary grid infrastructure. Debt financing is anticipated to account for 65–75% of capital expenditures (CAPEX), drawing interest from international lenders attracted by Serbia’s expanding renewable sector and the hybrid design of the project.
Projected equity returns vary based on market conditions: base case returns are estimated at 10–13% IRR; upside scenarios driven by volatility could yield 14–18% IRR; while downside risks associated with higher curtailment or price compression may result in returns as low as 8–10% IRR. The inclusion of storage technology is crucial for sustaining returns amid fluctuating market conditions.
The Fortis project exemplifies a broader transformation within Serbia’s electricity landscape as new capacity increasingly shifts towards renewable sources linked to market dynamics. While coal continues to dominate the energy mix, its position is gradually being challenged by rising operational costs and regulatory pressures related to EU carbon pricing mechanisms alongside growing investments in wind and solar energy.
As Serbia transitions toward a more flexible power market characterized by cross-border carbon-adjusted pricing and renewable intermittency, hybrid assets such as Fortis’s solar-plus-storage platform are poised to play an essential role in balancing supply-demand dynamics while supporting investment strategies throughout Southeast Europe.
