Bulgaria has moved rapidly from talking about storage to building a visible merchant-storage market. The most important signal came from Burgas, where Solarpro Technology, working with CATL, connected a 602 MWh battery storage facility to the electricity network. The project increases Bulgaria’s total energy storage capacity by about 10% and ranks among the largest battery storage facilities in Eastern Europe. Its purpose is not symbolic. It is designed to provide balancing services and manage fluctuations between electricity supply and demand.
This matters because Bulgaria sits in one of the most commercially interesting parts of the SEE power map. In the second half of June, IBEX Bulgaria averaged €99.72/MWh, only slightly higher than the first half of the month, while Hungary traded at €149.01/MWh and Romania at €146.80/MWh. That left Bulgaria at a deep discount to the northern premium markets. The spread is exactly the kind of environment where storage, interconnection and intraday optimisation become valuable.
The corporate activity is broadening. GEN-I Invest acquired three Bulgarian battery projects in Belovo, Momchilgrad and Parvomay, with combined capacity of 30 MW / 76 MWh. That raised GEN-I’s owned storage portfolio to 42 MW / 100 MWh, including its Slovenian battery asset. The company expects battery capacity under management in Bulgaria and Romania to reach around 800 MW this year and is targeting further acquisitions of about 100 MW. This is not a passive ownership model. GEN-I’s value proposition sits in optimisation, dispatch and market operation, exactly where merchant storage earns its return.
Energo-Pro has also entered the sector, commissioning a 10.75 MW / 24.31 MWh battery in Gorna Oryahovitsa. The investment was valued at €4.23 million, supported in part through Bulgaria’s National Recovery and Resilience Plan. The project is designed to charge during lower-demand periods and discharge when consumption rises or balancing capacity is needed. Energo-Pro expects a service life of at least 10 years and more than 7,000 charging and discharging cycles.
The regulatory backdrop is moving in the same direction. Bulgaria’s Energy Ministry is preparing amendments to the Renewable Energy Sources Law to support long-term power purchase agreements, accelerated renewable development zones, distributed generation and energy storage. That matters because storage investment needs more than battery containers. It needs grid-connection clarity, market-access rules, balancing-market participation and bankable revenue stacking.
Bulgaria’s storage buildout is also a response to its changing generation profile. Nuclear remains the anchor of the system, but solar is growing quickly and thermal output is under pressure from emissions, ageing plants and market economics. As solar expands, the system needs assets that can absorb midday surplus and return electricity during evening ramps. Batteries are the fastest deployable answer.
For investors, Bulgaria offers three overlapping storage models. The first is pure merchant arbitrage between low-price and high-price hours. The second is ancillary and balancing revenue from services to the transmission system. The third is co-located storage attached to solar or hybrid assets, improving PPA quality and reducing exposure to curtailment or price cannibalisation. The strongest projects will combine all three.
Bulgaria’s position is becoming more strategic because it connects cheaper southern Balkan price zones with higher-value northern and western demand centres. Storage will not only stabilise the domestic system. It will allow asset owners to monetise price volatility created by solar growth, interconnector congestion and evening scarcity. The country’s battery boom is therefore not a subsidy-driven footnote. It is the beginning of a new merchant infrastructure market.
