The evolution of South-East Europe’s electricity market is forcing a transition from single-asset economics to portfolio-level structuring. Merchant exposure—once the dominant model for renewable projects—is increasingly insufficient in a system defined by congestion, volatility and uneven grid access. Investors are responding by assembling integrated portfolios that combine generation, storage, transmission exposure and structured contracts, transforming fragmented revenue streams into predictable yield.
At the core of this transition is the recognition that no single asset class captures the full value of the system. A standalone solar project in a constrained node may deliver 5–7% equity IRR, reflecting curtailment of 20–30% and capture discounts of €15–25/MWh. The same project, relocated to a well-connected northern node near Subotica, can achieve 10–12% IRR with curtailment below 5%. The dispersion is too wide to ignore, and it cannot be diversified within a single asset.
Portfolio structuring addresses this dispersion by combining assets with complementary profiles. A typical regional portfolio now includes three layers. The first layer consists of core generation assets located in high-convergence zones—northern Serbia, western Romania or Hungarian border regions—where realised prices remain close to €80–90/MWhand output is stable. These assets provide base cashflow and support higher leverage, often 65–75% debt with DSCR above 1.30x.
The second layer introduces higher-return but more volatile assets. These include solar and wind projects in central or southern zones, where IRRs can reach 12–15% if volatility is properly managed, but fall significantly under pure merchant exposure. Integration with storage becomes critical here. A 100 MW solar + 200 MWh battery hybrid, with combined CAPEX of €150–200 million, can recover curtailed output and shift generation into higher-value periods, increasing realised prices by €10–20/MWh and stabilising revenues.
The third layer consists of flexibility and market-facing assets—standalone batteries, trading portfolios and capacity rights. A 200 MWh battery operating in Greece or Bulgaria generates €15–30 million annually, with IRRs of 12–18%depending on volatility. Capacity rights on corridors such as Bulgaria–Greece or Serbia–Hungary provide exposure to congestion rents, effectively adding an infrastructure-like income stream. Traders such as MET Group, Axpo, GEN-I and EFT integrate these elements, managing portfolios that span both physical and financial dimensions.
When combined, these layers produce a blended return profile that is more stable and attractive than any single component. A diversified portfolio can achieve equity IRRs in the 11–14% range, with lower volatility and stronger downside protection. This structure is increasingly aligned with the expectations of infrastructure investors, who seek predictable cashflows with moderate upside.
Geography remains central to portfolio design. Northern corridors—linked to Hungary and Romania—anchor the low-risk component, benefiting from strong interconnection and price convergence. Central zones—Serbia, Bulgaria and inland Romania—offer balanced opportunities, combining moderate spreads with manageable constraints. Southern markets—Greece, North Macedonia and Albania—provide high-volatility environments where storage and trading strategies can unlock significant value.
Cross-border integration enhances portfolio performance. Assets positioned across multiple markets can arbitrage both spatial and temporal spreads, reducing reliance on any single pricing regime. For example, a portfolio combining generation in Serbia, storage in Bulgaria and trading exposure to Greece can capture spreads of €20–50/MWh across borders, while also benefiting from intraday volatility within individual markets.
Contract structuring plays a critical role in stabilising revenues. Industrial PPAs with counterparties such as Zijin Mining, HBIS Group and aluminium producers in Greece provide a base layer of predictable income, typically priced at €65–85/MWh with premiums reflecting carbon compliance. These contracts anchor cashflows, enabling higher leverage and reducing exposure to merchant risk. The remaining output is optimised through market participation, often managed by trading partners.
Financing structures are evolving to accommodate this portfolio approach. Instead of financing individual projects in isolation, lenders are increasingly willing to underwrite portfolios, recognising the diversification benefits. Debt facilities may be structured at the portfolio level, with cross-collateralisation and cashflow pooling. This allows stronger assets to support weaker ones, improving overall leverage and reducing financing costs.
Development finance institutions, including the EBRD and EIB, are supporting this transition by providing flexible financing and risk mitigation. Their involvement is particularly important in emerging markets within the region, where portfolio structures can unlock projects that would be difficult to finance on a standalone basis.
Data and analytics underpin these strategies. Platforms such as Electricity.Trade provide real-time insights into price spreads, congestion and flow patterns, enabling dynamic optimisation of portfolios. Investors and operators use this data to adjust positions, manage risk and identify new opportunities as market conditions evolve.
The interaction between portfolio components is not static. As transmission capacity expands—through projects such as the Trans-Balkan Corridor (€300–400 million) and Bulgaria–Greece reinforcements—congestion patterns will shift, altering the relative value of different assets. Similarly, the growth of storage capacity, projected at 3–5 GW by 2030, may compress arbitrage spreads while increasing the importance of ancillary services.
Regulatory developments will also influence portfolio design. Market coupling, capacity allocation mechanisms and support schemes for storage and renewables will shape revenue streams and risk profiles. Differences between countries create both opportunities and challenges, requiring careful navigation of regulatory environments.
For investors, the move from merchant risk to structured yield represents a fundamental change in how value is created in the electricity sector. It requires a shift from project-level thinking to system-level strategy, where assets are selected and combined based on their interaction with the grid and the market.
South-East Europe provides a particularly clear illustration of this transition. The region’s combination of rapid renewable growth, uneven infrastructure and diverse market structures creates both risk and opportunity. By assembling portfolios that balance these factors—combining stable generation, flexible assets and market exposure—investors can transform a fragmented and volatile system into a coherent source of returns.
The grid, once a constraint, becomes a framework for structuring value. Within this framework, portfolios rather than individual projects define performance, and the ability to navigate complexity becomes the key determinant of success.
