Bulgaria has moved from battery-storage newcomer to one of Europe’s most closely watched markets in less than two years. The transformation is visible at Nova Zagora, where Enery inaugurated a 150 MW/601 MWh battery energy storage system in May 2026. Developed in less than a year, it is among the largest operating standalone batteries in Central and Eastern Europe.
The four-hour system, delivered with Sungrow and Sunotec, can absorb electricity during periods of low prices or renewable surplus and return it when demand and prices rise. The partners have discussed expanding storage in the Nova Zagora area to 800 MWh, with a potential increase to 1 GWh. No verified total private investment value for the operating facility was publicly disclosed in the reviewed announcements, so its capacity should not be confused with the value of the public support programme behind Bulgaria’s wider storage boom.
That programme is RESTORE, financed with €603 million from the EU Recovery and Resilience Facility. In a major award round, Bulgaria approved €587 million of subsidies for 82 standalone projects with a combined 9.71 GWh of energy capacity. The awards were substantially larger than the programme’s initial minimum objective, signalling intense developer interest and the falling cost of lithium-iron-phosphate systems.
The policy responds to a rapidly changing electricity market. Bulgaria, Greece and Romania have installed large amounts of solar power, producing more hours with very low or near-zero daytime prices. When the sun sets, prices can rise by more than €150/MWh within the same day. Batteries can monetise that spread while reducing renewable curtailment and the need for fossil-fuelled peaking generation.
Storage is also changing cross-border flows. In May 2026, Bulgaria reportedly imported power from Greece during a 15-minute period when Greek day-ahead electricity was priced at €0.01/MWh and Bulgarian electricity at €44.34/MWh, despite Bulgaria’s domestic production exceeding demand. Batteries acted as flexible consumers, absorbing cheap electricity; some energy later moved back toward Greece, while larger volumes flowed toward Romania. That is an early picture of Bulgaria’s potential role as a regional balancing hub rather than simply an electricity producer or transit country.
The benefits extend to grid security. Batteries respond in milliseconds and can provide frequency control, reserves and congestion management. They can reduce the strain created by abrupt changes in solar and wind output and support the regional system during short-duration supply disruptions. They do not replace transmission lines, seasonal storage or firm generation, but they can use existing infrastructure more efficiently.
The commercial outlook is not risk-free. Bulgaria’s early storage economics benefited from large price spreads and limited competition for ancillary services. If close to 10 GWh of subsidised projects enter operation within a short period, batteries will compete with one another. Daytime prices may rise as more systems charge, evening prices may fall as they discharge, and ancillary-service revenues may decline. This is beneficial for consumers and the grid but can undermine investment cases based on historic spreads.
Developers will therefore need diversified revenue stacks: energy arbitrage, balancing services, reserve products, co-location with renewables and potentially capacity payments or long-term tolling agreements. Regulation must also prevent batteries from being charged twice as both consumers and generators and ensure transparent access to all relevant markets.
Bulgaria’s storage build-out has become one of SEE’s largest flexibility experiments. The numbers are already substantial: 150 MW/601 MWh operating at Nova Zagora, potential expansion toward 1 GWh, €603 million of RESTORE funding, €587 million awarded, and 9.71 GWh across 82 supported projects. The commercial test will come as this new capacity begins competing for the same spreads, balancing revenues and grid connections.
