The deployment of battery energy storage systems (BESS) across Southeast Europe is progressing at an uneven pace. State subsidies and financing mechanisms have enabled the rapid implementation of BESS solutions in Greece, Romania and Bulgaria, while markets in the Western Balkans are lagging behind. However, the outlook remains positive, as experiences from neighboring markets and best practices from other parts of the European Union can help overcome initial challenges and streamline the deployment process. This was highlighted by participants of the panel dedicated to BESS at the Belgrade Energy Forum.

Among the technologies required for the energy transition, battery energy storage systems (BESS) stand out as a key factor for integrating electricity from intermittent renewable sources – wind and solar power – into the grid. There are few such facilities in Southeastern Europe and the segment is yet to even be fully regulated in the narrower Western Balkans region. The panelists at a session called Energy storage system market in SEE: trends and forecasts, at Belgrade Energy Forum (BEF 2025), outlined the trends in the budding market.

There are more and more cases of low and negative hourly prices in the wholesale electricity market in the region, providing a clear business case for BESS investments. In addition, the grid is often overloaded on weekends and holidays when solar and wind power production is high, given the weak demand.

Managing Director of Go2Power Consulting Goran Vukojević, who moderated the discussion, warned that negative prices may jeopardize system stability as well, if operators of power plants disconnect them from the grid at the same time, to avoid costs.

He highlighted the preparations in Serbia’s transmission system operator Elektromreža Srbije (EMS) for auctions for ancillary services and praised the company for transparency in regulating the competitive process. The other option for battery operators is to participate in the open market.

Region seen with 9 GW of BESS operating power in 2030

Ioanna Barouni from Aurora Energy Research said a total of 40 GW of solar and wind power is expected to be online at the end of 2025 in the SEE region, comprising 12 countries, including Hungary. In 2030, the level is expected to reach 70 GW, which is expected to be doubled to 145 GW by mid-century. As for BESS, projections stand at 9 GW in 2030 and 25 GW in 2050.

Barouni: We miss flexibility and ancillary services for transmission and distribution system operators

The countries of the region are retiring power plants that use fossil fuels, a firm capacity, in Barouni’s words, while adding renewables. “It’s not very easy to predict how the generation profile is going to be during the day, so we miss flexibility and we miss ancillary services for TSOs and DSOs,” she said.

The gap between power prices for midday and the evening is gradually increasing. Barouni explained that batteries “create some artificial demand and absorb these low prices.” At peak demand and with less renewables, a battery can replace expensive fossil fuels, lowering the price.

Serbia preparing auctions for ancillary services

Division Manager of transmission system operator (TSO) EMS Nikola Tošić acknowledged that Serbia is preparing auctions for ancillary services. He revealed that there would probably be one auction for 70% of the needed reserve in the first year. The next rounds would be more frequent, shifting toward daily auctions for balancing capacity.

In the verification process, EMS’s System Operation Department will first test the battery, Tošić added. State-owned power utility Elektroprivreda Srbije (EPS) already provides ancillary services to the TSO, so it won’t require tests, he asserted.

Serbian law defines ancillary services the same as European Union does

EMS drafted the new grid code, and it will publish the draft balancing market code for public discussion soon, according to Tošić. He said the domestic law defines ancillary services in the same way as the EU defines them in its legislation. One part is balancing services: frequency containment reserve (FCR, primary), automatic frequency restoration reserve (aFRR, secondary) and manual frequency restoration reserve (mFRR, tertiary). The other part are non-frequency services – energy.

“We think that it would be good to incentivize the periods of the year or periods of day when the needed amount of reserve is more attractive or more in demand,” Tošić said.

Fortis Energy moving ahead with battery investments regardless of government support schemes

Fortis Energy’s Chief Executive Officer for Eastern Europe Nikola Oklobdžija considers the lack of regulation to be the biggest challenge for developers. An investor can currently only focus on charging the batteries when the prices are low and sell when they are high, he underscored.

The Turkey-based company develops photovoltaic, wind power and BESS projects in the region. The first bigger investments in renewable electricity plants with energy storage are the ones that will break the ice, in Oklobdžija’s opinion.

“Of course, it helps if you have a CfD contract, so the banks will look at it more favorably,” he stated. Oklobdžija added that companies need to be able to present revenue to the lenders and what the fees are for renting the capacity or providing different services.

Bankability depends on state support and PPA contracts, cash flow models and insurance

In the meantime, Fortis is examining the experiences in Bulgaria and Greece, which have already held auctions for standalone batteries. Financing a project is easier with a CfD – contract for difference, but the company is determined to push ahead anyway, Oklobdžija stressed.

In North Macedonia it commissioned a solar power plant in Oslomej and recently contracted a BESS to be added to the facility. Oklobdžija said it wasn’t a requirement but that Fortis opted for energy storage because of market pressure with prices and occasional curtailments, like during Easter last month.

The introduction of ancillary services would facilitate the development for standalone battery systems, he explained.

Cerović: First there will be more projects for colocated BESS units than for standalone facilities

Head of Specialized Lending at UniCredit Bank Serbia Svetlana Cerović highlighted the intensive activity in Germany and Italy, for instance, but also in neighboring Romania. UniCredit is present in those markets and is analyzing the development of the battery storage market, she pointed out, arguing that the best practices in the EU are the best way for building and financing battery storage.

Cerović said there would first be more projects in the region for BESS colocated with renewable energy plants than standalone units.

She suggested that the proposed investments that include storage should be better pondered at the next renewable energy auction in Serbia. It is in the country’s interest to enable providing flexibility and to support the projects, she said.

There may be a rationale for subsidizing prosumers to add storage in Serbia, Cerović said. Turning to small-scale projects, she expressed the belief that power purchase agreements (PPAs) are “convenient” for them. She is recommending dedicating a certain capacity for the category at the next auction in the country.

The first projects in Serbia, conditioned by energy storage requirements for a grid connection, are in the process of negotiating financing, according to Cerović.

Fire protection is especially significant for insurers

Renewable Energy Insurance Broker (REIB) has insured some 4 GWh of energy storage capacity in Bulgaria and just as much elsewhere in the world, Business Development Manager Dimitar Dimitrov said. Developers should contact insurance companies when the design is done, as well as for cargo insurance, he suggested and added it is particularly important for projects that get subsidies.

“We’re not only insurance brokers, but we’re also investors, which helps us understand a bit more about the clients’ needs, and what we can definitely do more in cases of coverage. Understanding clients’ needs helps us also prevent risks that could occur during certain stages,” Dimitrov stated.

Most insurers prefer at least a six-meter distance between containers or rows of three to four containers holding batteries, he said. It is the most important factor in fire protection, in Dimitrov’s opinion. When the distance is shorter than three meters, a firewall is required for insurance, he explained.

The next segment is construction insurance. For insurance companies, it is not a higher risk profile, Dimitrov asserted. Next, he recommended operational risk insurance including coverage for business disruption, and insurance against cyberattacks. In such events, the grid connection can be damaged, the company’s representative pointed out. “Insurance policies are definitely bankable,” he added.

Bulgaria has completed its tenders for state support to BESS combined with renewable energy plants, and for standalone units. But even before subsidies, batteries have been delivered and facilities are under construction, Dimitrov stressed. Many photovoltaic projects in Bulgaria have emerged in the past few months and most of them include BESS, he said.