According to Aurora Energy Research, Bulgaria is on track to have around 1.8 GW of battery energy storage systems operational by 2026, despite auction results that suggest a far larger pipeline. The estimate is part of Aurora’s newly launched Flexible Energy Forecast service for Bulgaria, which assesses how recent storage auctions, system constraints and market dynamics translate into deliverable capacity and investor returns.
Since 2024, Bulgaria has run a series of state-backed storage auctions capped by budget rather than by capacity. The result has been a strong oversubscription, with winning projects amounting at least 5 GW of supported capacity, three to four times the initially announced targets. While this confirms a high level of investor appetite and positions storage as a core component of the power market, it also raises questions about how much of this pipeline can be built on schedule and absorbed by the market.
Aurora’s central outlook points to significant practical bottlenecks. Limited EPC capacity, financing constraints and rising concerns over market cannibalization are expected to slow deployment, meaning only a fraction of awarded projects are likely to reach operation in the near term. On this basis, Aurora forecasts around 1.8 GW of operational BESS by 2026, increasing to approximately 3 GW by 2030. The challenge for Bulgaria, the analysis suggests, is shifting from attracting capital to managing delivery and sequencing capacity without eroding project economics.
To capture the uncertainty around build-out speed, Aurora also modelled a high-penetration scenario in which BESS capacity reaches 4.5 GW by 2030. Under these conditions, returns come under pressure, with IRRs falling by around two percentage points for standalone batteries and one point for collocated projects. Even so, hybrid assets remain more resilient, supported by higher capture prices for solar as additional flexibility enters the system.
In the near term, Aurora sees a clear advantage for early entrants. Elevated wholesale price spreads and balancing-market volatility, combined with limited existing flexibility, support strong merchant revenues in the first years of operation. A two-hour standalone battery commissioned in 2026 is expected to generate around 18% more cumulative cashflow over its first five years than an identical project coming online in 2029, highlighting the growing value of timing.
Auction design is also shaping technology choices. The per-MWh bidding structure and local grid constraints favor longer-duration storage, with many projects expected to adopt around four hours of duration. Although these systems capture lower arbitrage revenues per MWh, they benefit from lower CAPEX per unit of energy due to shared grid infrastructure and more efficient use of limited connection capacity, resulting in higher overall returns.
Against this backdrop, Aurora positions its Bulgaria Flexible Energy Forecast as a decision-support tool rather than a capacity tracker. By linking auction outcomes with grid realities, market signals and technology economics, the service aims to help developers, investors and policymakers distinguish between headline ambition and bankable, system-relevant deployment as Bulgaria’s storage market enters a more disciplined phase.