Regarding the share of the system for battery-powered storage, the world has a new and unexpected champion – Bulgaria.
As recently announced by the Bulgarian Chamber of Commerce, Bulgaria recently exceeded 3 gigawatts in total capacity of battery storage systems, which is about 16% of Bulgaria's total power capacity, writes Nikola Zdravković for the Klima 101 portal.
It is the largest share of batteries in the power system in the world, but what is astonishing is the speed of installation of these systems.
Namely, just two years ago, that is, in 2024, the total battery capacity in Bulgaria was almost zero, as shown by the ENTSO-E platform.
Such a rapid development of batteries in Bulgaria was helped by the previous, also impressive development of solar in this country.
Solar capacities in Bulgaria have increased from around 1 GW in 2020 to over 6 GW in early 2026. For the sake of comparison, in Serbia they are currently estimated at around 200 MW, which is around 30 times less.
Large stand-alone power plants
Solar is also the largest single source of electricity in Bulgaria, and in addition to roofs and terraces across the country, significant capacities of large, independent power plants have also been built in Bulgaria.
However, such a rapid development of solar energy, which happened not only in Bulgaria, but also in Greece, Romania, and Hungary, created new challenges.
One of the biggest is the instability of production. As a variable source, solar only produces electricity during the day, so countries like Bulgaria see large daily oscillations in output.
In fact, the oscillations are so great that during the day, while solar is working, it happens that production exceeds consumption, to such an extent that it becomes impossible to sell the surplus - so the price drops to zero, or "minus". In fact, producers pay for someone to take over the electricity they produce.
This is a big challenge for investors, who by investing in solar today risk becoming market losers. This is an important problem for countries that have developed significant capacities of variable sources - and it is solved in different ways.
Investing in storage
One solution is contracts that guarantee producers a certain purchase price (which also exists in Serbia) - but in 2023, through new energy plans, Bulgaria decided to solve this problem first through investments in storage.
Namely, batteries are an ideal partner for variable sources: they enable surpluses, for example during the day from solar, to be stored and used or sold when production drops - in the evening or during the night.
In order to develop battery capacities, in 2023, with the support of the European Union, Bulgaria introduced a series of benefits for their installation, including subsidies for investors.
The result was a drastic growth: from almost "zero" at the beginning of 2024, to over 3 gigawatts of capacity at the beginning of 2026. As the Bulgarian Chamber of Commerce writes, the boom continues, and it is expected that capacities will reach even 5 gigawatts by the end of this year.
"Regional battery"
Such rapid development has cost the state and investors about two billion euros so far, and those investments will not only bring more stable incomes and more favorable market conditions.
In this way, Bulgaria has become a "regional battery" that balances electricity production and consumption, and contributes to price stability for the entire region.
Although other storage capacities can also play a balancing role - for example, gas or reversible hydropower plants - batteries have proven to be the fastest and most advantageous solution by far.
For the sake of comparison, the investments that enabled Bulgaria to transform its energy sector in this way - two billion euros - are close to the amount that Serbia spends on importing oil and gas in just one year. And that was before the current crisis, which drastically raised oil prices around the world.
Where, in other words, will we spend the money we have as a society? Will we continue to throw it into the abyss of fossil imports, which we know has no bottom and no end, or will we invest it in the rapid construction of our own energy capacities, which, as Bulgaria has shown us, can be both renewable, clean and stable?
What are Serbia's plans?
In recent years, Serbia has been showing increasing interest in the application of battery systems for the storage of electricity.
The largest planned project is a joint investment of the Electric Power Company of Serbia (EPS) and the Hyundai Engineering - UGT Renewables consortium. The project includes the construction of solar power plants with a total installed capacity of 1 GW, along with battery storage facilities with a capacity of 200 MW and a capacity of 400 MWh. The completion of the project is planned by 2028, and it is expected to represent the largest system for battery storage of electricity in Serbia.
Among the significant private investments, the "Night 1" project near Sremska Mitrovica, which is being developed by Fortis Energy, stands out. This project envisages the construction of a battery system with a capacity of 36 MWh connected to a solar power plant with a capacity of 90 MW. At the beginning of 2026, a permit was issued for the construction of this plant, which made an important step towards its realization.
In addition to the "Night 1" project, Fortis Energy is developing other projects in Serbia that combine solar power plants and battery energy storage. The total planned capacities of these plants are measured in hundreds of megawatts.
A significant contribution to the development of this area is represented by the pilot project of the Poweroad company in Smederevo. The project involves the construction of a battery storage facility with a power of 0,5 MW and a capacity of 1 MWh, connected to a solar power plant. The start of the system is planned for 2026.
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