The monetisation of South-East Europe’s power system is no longer confined to generation. Transmission corridors, storage assets and hybrid portfolios are increasingly being priced as investment products, each with distinct return profiles shaped by congestion, volatility and grid topology. The convergence of these asset classes is producing a layered return structure where value is extracted not only from electricity production but from the control of flows, timing and access to constrained infrastructure.
Transmission sits at the foundation of this structure. While traditionally regulated, the financial characteristics of key corridors increasingly resemble infrastructure assets with predictable cashflows. Congestion rents across major interconnections—Serbia–Hungary (€70–120 million/year), Bulgaria–Greece (€150–200 million/year), Romania–Hungary (€100–150 million/year) and the Montenegro–Italy HVDC link (€70–150 million/year)—collectively generate more than €0.8–1.2 billion annually. These revenues underpin CAPEX programmes exceeding €2.5–4.0 billion through 2030, including projects such as the Trans-Balkan Corridor (€300–400 million) and Bulgaria–Greece reinforcements above €500 million.
From an investor perspective, direct access to these revenues is limited by regulatory frameworks, but indirect exposure is increasing. Participation in transmission projects, partnerships with system operators or investment in merchant interconnections provides entry points. Expected returns for regulated grid assets remain in the 6–8% equity IRR range, reflecting stable, tariff-based income. However, projects with merchant characteristics—such as HVDC links—can achieve higher returns, particularly when linked to structurally divergent markets.
Storage occupies the next layer, bridging the gap between generation and transmission. Unlike transmission, its returns are market-driven, derived from arbitrage and ancillary services. Across South-East Europe, a standard 200 MWh battery system, with CAPEX of €80–120 million, generates annual revenues of €15–30 million in Greece and €10–20 million in Bulgaria or Romania, depending on volatility. After operating costs, this supports equity IRRs of 12–16%, with upside potential to 18–20% in high-spread environments.
The risk profile of storage differs from both generation and transmission. Revenues are sensitive to price spreads, which are themselves influenced by renewable penetration and grid constraints. As deployment increases—projected at 3–5 GW regionally by 2030—competition for arbitrage opportunities may compress spreads, moderating returns. However, the expansion of ancillary service markets and the increasing need for flexibility provide counterbalancing revenue streams.
Hybrid assets—combining renewable generation with storage—represent the most dynamic segment of the market. By integrating production and flexibility, these projects capture both energy value and timing value. A typical configuration in the region is a 100 MW solar plant paired with a 200 MWh battery, with combined CAPEX of €140–200 million. The battery component increases realised prices by €8–20/MWh, adding €10–25 million in annual revenue and lifting equity IRRs from 7–10% (standalone solar in constrained nodes) to 11–15%.
These hybrid structures are particularly effective in zones with high curtailment and volatility. In southern Serbia, North Macedonia and parts of Bulgaria, where curtailment can exceed 20–25%, storage reduces lost output and shifts generation into higher-value periods. This dual effect not only increases revenue but also stabilises cash flows, improving bankability. Lenders respond by increasing leverage from 50–60% to 65–75%, recognising the enhanced predictability of hybrid portfolios.
The interaction between asset classes creates a layered return profile across the grid. Transmission provides stable, lower-risk income; storage offers higher returns linked to volatility; hybrid assets combine elements of both, balancing risk and reward. Investors can position themselves across this spectrum, constructing portfolios that align with their risk appetite and return targets.
Geography remains a critical determinant of returns. Assets located near high-value corridors—such as the Bulgaria–Greece interface or the Montenegro–Italy HVDC link—benefit from strong price differentials and high utilisation. In these zones, storage and hybrid projects achieve upper-range returns, often exceeding 15–18% IRR. In more stable northern zones, returns are lower but more predictable, reflecting reduced volatility and curtailment.
The role of traders is central to monetising these assets. Firms integrate generation, storage and capacity rights into unified portfolios, optimising across both space and time. Their ability to capture value from multiple layers of the system—arbitrage, congestion and flexibility—enhances overall returns and reduces exposure to any single risk factor.
Platforms like Electricity.Trade provide the data infrastructure supporting these strategies. By tracking price spreads, ATC utilisation and congestion patterns, they enable real-time optimisation and long-term modelling. For investors, this data is essential for valuing assets and understanding how returns evolve under different market scenarios.
Financing structures are adapting to this multi-layered environment. Traditional project finance, focused on single assets, is giving way to portfolio-based approaches that combine generation, storage and contractual revenue streams. This allows for risk diversification and more efficient capital allocation. Debt providers are increasingly comfortable financing hybrid portfolios, particularly when supported by long-term contracts or strong counterparties.
Development finance institutions, including the EBRD and EIB, play a catalytic role in this transition. By supporting both transmission and renewable projects, they facilitate the integration of asset classes and reduce systemic risk. Their involvement is particularly important in emerging markets within the region, where private capital may be more cautious.
Regulatory frameworks are gradually aligning with these developments. Recognition of storage as a distinct asset class, access to ancillary service markets and clearer rules for hybrid projects are all contributing to a more investable environment. However, differences between countries remain, creating a patchwork of opportunities and challenges.
The pricing of the grid itself reflects a broader transformation in the energy sector. Value is no longer derived solely from generating electricity but from managing its movement and timing within a constrained system. Transmission, storage and hybrid assets each play a role in this process, creating a complex but investable landscape.
Across South-East Europe, this landscape is still evolving. Transmission capacity is expanding, renewable generation is increasing and market structures are adapting. The interaction between these factors will determine how returns are distributed across asset classes. For investors and developers, the ability to navigate this interaction—to position assets where they can capture both stability and volatility—has become the defining factor in achieving competitive returns within the region’s power market.