Greece supplies Bulgaria with electricity during the day, while in the evening it buys electricity from Bulgaria, the online edition of the newspaper “Kathimerini” writes, citing an analysis by the European Commission.
The data show that battery storage systems allow Bulgaria to take advantage of cheaper daytime energy and export it in the evening, the Greek publication writes.
In August, electricity imports from Greece to Bulgaria reached 750 megawatts in the middle of the day. At around 9 p.m., Bulgaria’s exports to Greece stood at approximately 700 megawatts. The situation reflects Bulgaria’s growing ability to store cheaper daytime electricity produced by solar parks and then export it when prices are higher.
According to the publication, this is due to the rapid growth in solar energy production and battery energy storage infrastructure. The share of solar energy in Bulgaria’s electricity generation is increasing from 4 percent in 2021 to 21 percent in 2026. At the same time, installed photovoltaic capacity has grown from 1.3 gigawatts to 7.2 gigawatts.
The European Union’s Recovery and Resilience Facility has supported half of the growth in solar capacity through a program with a capacity of 3.2 gigawatts. The program combines renewable energy installations with systems for storing it.
Bulgaria currently has battery electricity storage capacity exceeding 16 gigawatt-hours. During peak periods, batteries can store up to 30 percent of the electricity produced, according to an analysis by the European Commission.
The data indicate that in August 2024, electricity prices during the evening hours were 150 percent higher than the average daytime values. Two years later—in August 2026—the difference had fallen to 40 percent
The EC notes that Bulgaria has modernized its transmission network, simplified procedures for issuing permits and connecting to the grid, strengthened its links with Greece and Romania, and opened its market to balancing electricity in 2025. The modernized network can accommodate an additional 5.4 gigawatts of capacity from renewable sources.
Greece is also taking steps to expand its electricity storage capacity, “Kathimerini” reports. The Ministry of Energy has announced that 831 applications have been submitted to connect facilities with a total capacity of 12,319 megawatts to the grid as part of a procedure covering projects for battery systems with a capacity of up to 4,700 megawatts.