As a record drought crippled power generation across Eastern Europe, Bulgaria has emerged as a regional bright spot, thanks to a rapid build-out of battery storage that is now paying dividends. The country, one of the EU's poorest, has seen its electricity exports more than double during the summer months, a direct result of investments made in the past two years.
Around one hundred battery energy storage systems (BESS) are now operational in Bulgaria, most of them commissioned since 2024. These projects repurpose former industrial sites, airfields, and even integrate into existing power stations, including coal-fired plants. The scale of deployment is unprecedented in the region, according to Stavros Papathanassiou, a professor at the National Technical University of Athens. "The scale and speed of storage deployment in Bulgaria is unprecedented in a European context," he told AFP.
Low administrative hurdles, a receptive market for clean energy, and EU funding have all contributed to Bulgaria's leading role. The batteries absorb surplus solar power during the day and release it when demand peaks, a function that proved crucial when exceptionally low water levels on the Danube disrupted nuclear and hydroelectric plants across Eastern Europe, driving up import demand.
In July and August, Bulgaria recorded net electricity exports of around 830 gigawatt-hours per month, more than twice the average for May and June. Romania alone accounted for nearly half of July's exports, valued at an estimated €74 million. This performance underscores how storage can turn a vulnerability into an opportunity.
From coal to batteries
At Maritsa East 3, once Bulgaria's second-largest coal-fired plant, the transition is visible. Built under communism with four generating units, the plant sharply reduced coal operations in 2024, repurposing its grid connection for a battery facility. "We could leverage the large connection to the grid. We decided to disconnect one coal unit and connect batteries," said Vassil Shtonov, head of Bulgaria operations for ContourGlobal, the British-based power company. "Coal is out, battery is in. It was the right place at the right time," he added, though he cautioned that Bulgaria should maintain a minimum coal-fired reserve for severe winters or gas supply disruptions.
Bulgaria accounted for about 9% of European battery-storage additions and about 2% of solar additions in 2025, according to Lennart Herrmann at the Munich-based research firm FfE. He believes Bulgaria "can serve as a positive example for other European nations," showing that "the right incentives...can enable a swift energy transition."
The Bulgarian energy ministry reports around 5.7 gigawatts of operational battery-storage capacity as of this month—nearly a quarter of the country's total installed power-generation capacity and more than five times Romania's operational battery capacity. Businesses have also signed contracts for nearly 14 gigawatt-hours of large-scale storage, part of which is already online. "The aim is for storage systems to find a sustainable role in the market," the ministry said, adding that it "must go hand in hand with other investments, such as in transmission and distribution grids."
Nikola Gazdov, president of Bulgaria's Association for Production, Storage and Trading of Electricity, attributes the boom to a combination of factors rather than a crafted strategy. "Everything happened almost by chance," he told AFP. Solar capacity has expanded rapidly, creating growing daytime surpluses, and in Bulgaria large battery projects can be up and running in just nine to 18 months—far quicker than many solar or wind projects.
But battery storage has limits. Grid connections with neighbouring countries are constrained in capacity, and current batteries can store power only for short periods, "typically between one and six, sometimes up to eight hours," said Herrmann. They can support the grid during temporary drops in supply but cannot replace a nuclear reactor that goes offline due to drought. Moreover, their success could erode their own profitability: as more BESS operators buy low and sell high, the price gap narrows.
Still, Bulgaria's experience offers a practical model for integrating renewables and storage, especially as Europe grapples with the energy demands of AI and data centres. The country's ability to turn a crisis into an export opportunity is a lesson for the wider continent, even as Brussels considers new powers to manage electricity cuts in emergencies.
