Bulgaria has unexpectedly emerged as one of Europe's battery storage leaders, earning the nickname "Balkan battery" as its installed capacity doubled in a single year.

Backed by €700 million (USD 783.86 million) in EU grants, the Black Sea country has grown its battery fleet to about 6GW, up from roughly 3GW a year earlier. The combination of EU funding and legislative changes that attracted private investment has allowed Bulgaria to store daytime solar energy and release it during evening peak hours.

Exports surge as batteries absorb solar

The effect on cross-border trade has been striking. According to APSTE data, Bulgaria increased electricity exports by 62% year-on-year to 3.5TWh. The country now exports up to 50,000MWh per day — equivalent to about 2,000MW per hour on average, roughly the capacity of the Kozloduy nuclear power plant, according to Dimitar Zarchev, head of the Bulgarian electricity system operator's central dispatch office.

Part of Bulgaria's electricity exports went to Romania, which had to shut down a nuclear reactor in August due to drought lowering Danube River levels used for turbine cooling.

Increased battery capacity also helped Romania maintain reservoir levels by reducing the need for hydropower traditionally used for peak demand — a concrete example of storage delivering system-level value across borders during the July–August heat waves.

Greece: a solar boom without the batteries

The contrast with Greece is stark. Despite more than tripling solar capacity between 2020 and 2025 according to IRENA, Greece has lagging battery deployment and still relies on gas imports for evening peak demand. Even after three rounds of standalone battery auctions since 2023, the country installed only its first unit in April; total storage is expected to reach 1GW by year-end, a small fraction of Bulgaria's capacity.

The cost of that lag shows up in consumer bills. In the first half of the year, Greece's average retail electricity price excluding taxes and levies was €0.1967/kWh, compared with €0.1117/kWh in Bulgaria, according to Eurostat. Greek officials expect an additional 5GW of battery capacity by 2030, supported by EU funds intended to lower energy prices.

Winter and grid constraints ahead

Bulgaria's advantage is not without limits. Batteries are expected to have less impact in winter, when shorter daylight reduces solar output and the country relies more on traditional power plants. Further growth faces the need to expand Bulgaria's electricity grid. Faster capacity growth has also narrowed price spreads, reducing revenue from simple energy arbitrage; Bulgaria's Energy Ministry told Reuters that battery operators may need to participate not only in cheap-versus-expensive hour arbitrage but also in balancing markets.

Across the EU, progress has been slowed by long waits for regulatory permits and grid connections, though deployment is expected to accelerate, especially in Germany and Italy.

Source: RNPi (citing APSTE, Eurostat and Reuters)

This article was assisted by AI analysis. Please refer to the original source for official information.