Bulgaria posts 528 million euro net electricity export surplus

Bulgaria exported a net 528 million euros of electricity during June, July, August, and September, with imports totaling only 10 million euros during that period, according to calculations based on data from the Energy System Operator (ESO) and ENTSO-E.

Battery Storage Turns a Profit

The energy sector recorded a significant surplus this summer, driven largely by battery storage facilities. These systems generated 181 million euros in profit during the four-month period by exploiting price differences between low-cost daytime charging and high-demand evening hours.

Battery storage units discharged 289 million euros worth of energy while charging for only 108 million euros, resulting in an arbitrage margin of 181 million euros.

This performance relies on specific conditions. First, Bulgaria used Recovery and Resilience Plan funds to acquire storage capacity, creating opportunities to buy power when prices are low and sell during peak hours. Second, nuclear power plants in neighboring Romania and Hungary were offline due to low water levels in the Danube River, increasing demand in the region. Simultaneously, limits on solar power were lifted, allowing production to exceed 5,000 MW.

On September 14, the country set a record export of 51.295 GWh in a single day, while imports dropped to zero.

Battery storage accounted for roughly half of the total export volume, with pumped-storage plants like Maritsa East and Belene adding over 208 MW of stored energy. Coal plants also increased output from 340 GWh in June to 844 GWh in September.

Despite their high profitability, batteries cover a small fraction of total production, concentrating revenue in peak pricing windows.

Winter Challenges and Future Projections

Winter will bring different conditions to the Bulgarian energy market. Solar power output decreases significantly during the colder months, removing a major source of daytime energy. Gas power plants in Greece and Hungary will likely dominate the market. Together, these facilities have a capacity of 6.68 GW and 3 GW respectively, giving them the power to set peak prices.

Analyst Ivan Yonchovski notes that water reservoir levels in Bulgaria are currently about 25 to 29 percent higher than the same period in previous years. However, levels are depleting faster than usual in the last month. He advises the National Electric Company to preserve water for hydro plants during the current surplus instead of drawing it down for export.

Looking ahead to 2026 and beyond, Romania plans to add more than 10,000 MW of wind and solar capacity by 2030. This massive increase will create a long-term energy surplus in the region. The abundance of new power will push expensive generation sources out of the market and permanently lower prices.