Bulgaria’s battery fleet has reached more than 6.2 GW of power capacity and 19 GWh of energy capacity, according to the latest estimates, well above the 3,000 MWh target of its public support programme. The expansion signals a shift from a deployment phase, when construction was rewarded, to a market where competition and operational performance will shape returns.
Public support and projects drive storage expansion
The RESTORE programme allocates 603 million euros from the Recovery and Resilience Facility for usable energy storage in Bulgaria. The build-out shows how public support can accelerate battery deployment, while the larger fleet increases the importance of projects earning returns beyond subsidies and early scarcity rents.
At Tvarditsa, a programme covering three battery-storage projects includes more than 2.3 GWh of combined storage and investment exceeding 350 million euros. Its first site is a five-hour battery system with 300 MWh of storage. The European Bank for Reconstruction and Development is financing the Tenevo battery project alongside Raiffeisen; Tenevo has 246 MW of power capacity and 512.5 MWh of energy capacity.
Competition will test project revenues
The next test for the expanding fleet is whether projects can secure attractive returns in merchant markets as public support and early scarcity rents fade. Batteries will compete for the same solar-hour charging opportunities, evening price spreads and balancing services, potentially compressing revenues across the market.
As competition grows, projects with lower financing costs, longer duration, better optimisation or more advantageous grid locations are expected to outperform generic two-hour arbitrage assets. Bulgaria is entering a phase that rewards operational efficiency and capital discipline rather than construction alone. Its experience is expected to provide a regional benchmark for Serbia, Romania, Croatia and the Western Balkans as they expand their storage fleets.