Digitalization and massive use of data are crucial for providing flexibility services that bring benefits for transmission system operators and renewable energy producers. Aggregators and software firms have developed the technological solutions. However, the process, together with the introduction of flexibility platforms, requires a long time. The reforms also have to be accompanied by market liberalization and end consumers acting as active buyers, according to the participants of Belgrade Energy Forum 2025.

The panel on flexibility services called Market Flexibility: The Backbone of a Resilient Energy System was one of eight that were held at Belgrade Energy Forum 2025 (BEF 2025).

The conference, organized by Balkan Green Energy News, welcomed four hundred participants from more than 30 countries from the region, Europe, and beyond.

“Flexibility has been promoted in Europe as a buzzword, sometimes reflected as demand-side flexibility, but it represents so much more. It includes supply-side flexible assets like hydro, biomass, storage, as well as grid-side flexibility,” according to panel moderator Elena Boškov Kovacs, co-founder and CEO of Blueprint Energy Solutions, and a leading voice on market flexibility in Europe.

Serbia will introduce a flexibility services market

Serbia’s transmission system operator (TSO) Elektromreža Srbije (EMS) is preparing to liberalize the ancillary services market. The country adopted the Law on Energy in November and implemented a large proportion of the European Union’s Electricity Integration Package (EIP) while the remaining parts will be transposed through bylaws.

“The balancing capacity market will be liberalized from next year. We will have new participants – active buyers and independent aggregators,” said Marko Zarić, Head of the Market Operations sector of EMS.

He stressed that the TSO is trying to ensure that no market participant is impaired by engaging flexibility resources or demand side response or a balancing service.

“EMS has finished drafting the new market code, which envisages dual balancing responsibility. We will launch a public debate on the act. The TSO estimates that it is the best solution to open the market of flexibility services,” he noted.

Bernard: Technology is on our side

NGEN CEO Roman Bernard expressed the opinion that the region is moving in the right direction, and suggested to regulators to look around and implement best practices. If the participants in the market are motivated, things will go forward, he added.

Back in 2019-2020, when NGEN started its operations in Slovenia, flexibility services were a pioneering job. The Slovenian energy company, the technology sponsor of the BEF 2025 conference, specializes in premium battery energy storage systems (BESS) and smart energy solutions.

According to Bernard, the balancing services market in the EU is well developed thanks to balancing platforms MARI (Manually Activated Reserves Initiative) and PICASSO (Platform for the International Coordination of Automated Frequency Restoration and Stable System Operation).

“We have 150 employees, and we can do everything. Technology is on our side and the sky’s the limit,” he stressed.

For example, NGEN solutions can provide monetization of battery energy storage systems (BESS), and the only thing that is needed is investors in such facilities.

Digitalization is the only way forward

The representatives of aggregators KOER and Alteo and software company CyberGrid all agreed that digitalization and the use of data are crucial for the energy transition.

Compared to NGEN and its use of BESS, Croatia-based KOER, a pioneer in virtual power plants in the region, is utilizing existing assets, like diesel generators, or employing the flexibility intrinsic to most manufacturing companies; for example, cement factories and wood manufacturers.

Existing assets work well, not just batteries, KOER COO Luka Renko stressed.

The only problem, in his words, is digitalization. The majority of the said firms aren’t ready to connect to the platform to be automatically switched on and off. The markets are getting faster and faster, so digitalization is the only way forward, Renko claimed.

Alteo, a leading Hungarian aggregator, also believes in lots and lots of data, which back up its scheduling and contribute to the security of supply.

Tokai: Alteo is looking for partners in the region

“Our superpower is providing scheduling services with the support of AI, including lots of data,” said Magdolna Tokai, Deputy CEO for International Relations and Corporate Services of Alteo.

Hungary has experienced a photovoltaic boom in the past four or five years, with the installation of almost 8,000 MW. It’s good for greening power production, but not from the perspective of a TSO, and that is where aggregators come into the picture, she added.

Alteo is combining conventional resources like gas-fired power plants with renewables. It currently has 140 MW in renewable resources, it manages 2,000 MW of third-party solar, and operates two virtual power plants. The company is providing the service to small photovoltaic facilities and the TSO.

Alteo is integrating solar energy in a product that is close to baseload, and placing it on the market. It translates to lower balancing costs for solar and a more stable product for the TSO, she explained.

Serbia is facing a challenge from the upcoming 1.2 GW of solar power

Alteo has just started implementing its new strategy for regional growth by exporting know-how on balancing services and providing flexibility to market players.

According to Nikolaj Candellari, Project Manager and Market Intelligence of CyberGrid, real-time data gives a TSO and other market participants the possibility to understand where they are.

He recalled that, over the years, the market went from 15-minute time stamps, down to one minute, and that now it is only two seconds. The improvement helps dealing with challenges, and CyberGrid knows a lot about such issues.

“For Serbia, the challenge comes with 1.2 GW of solar, which will be installed next year. So if you don’t see it as a challenge, ask yourself who needs 1.2 GW of energy at noon on Sunday,” Nikolaj said.

Over its 15 years of existence, CyberGrid developed good examples of how to exchange data with assets and TSOs.

“Assets are always the same, no matter the country, but to have this data exchange with TSOs, or even market platforms, that is something I think we need to do in the future in Southeastern Europe,” he stressed.

How to get to the future: properly liberalize markets

Elena Boškov Kovač (Blueprint Energy Solutions) asked the panel participants what the solution is for addressing different types of flexibility assets including prosumers.

“How do we avoid getting stuck in the easy-to-commercialize part of the aggregation, and postpone the true demand response, which is needed to avoid the issues with negative pricing and electricity market swings?” she asked.

There is no dilemma for Nikolaj Candellari (CyberGrid): “I think we can connect everything, including households.”

It is something futuristic, he said. “We have to try to go as low as possible and connect everybody because, in the end, it’s not different if you have a 1 MW battery or 100 smaller residential ones” of 1 MW combined, Candellari asserted.

His company is currently implementing a project to integrate 150 batteries of 2 MW overall and put them on the market.

The batteries can drive the prices for end users down by 25% within five years

Candellari and Roman Bernard (NGEN) alike highlighted the factor of market motivation.

Bernard said motivation is created by the market. The imbalance price can go up to EUR 15,000 per MWh, and it is the signal and the motivation to fix everything, in his opinion.

He is convinced that batteries can lower the prices for end users by 25% within five years if dynamic prices are applied.

According to Nikolaj Candellari, participants will come to the market, as long as it’s not too regulated. As an example of a non-functional market, he mentioned Bulgaria, where the capacity price for downward regulation is zero.

“So, why would anybody join the market, if the capacity price is zero? Get the market running and you will get participants and capacity needed to balance it,” he said.

Tokai: We need a proper energy mix

Magdolna Tokai (Alteo) has a slightly different view of the markets. She recalled that episodes of negative prices are happening in Hungary, while that last August and September very high prices were recorded on HUPX, up to EUR 1,000 per MWh, and above EUR 500 per MWh in Croatia and Serbia.

“We have to be prepared for that, which is data, data, data, and the cooperation of all the market players, providing the proper energy mix, and the proper product for the TSO,” she pointed out.

Marko Zarić (EMS) stressed time as a vital ingredient for developing markets. A transition from the regulated market to the truly open market envisages multiple steps that take time, he said.

Flexibility platforms need time for implementation

Another big change are the balancing platforms developed by aggregators. Traditionally, TSOs were buying the same kind of standardized product, for example, SCADA, EMS, and other market applications, with more or less the same kind of functionalities.

Elena Boškov Kovač (Blueprint Energy Solutions) brought up the question of a more standardized approach. “Before we start talking about interoperability and connecting with everything else, would it be good to at least have platforms with similar kinds of functionalities and services provided?” she asked.

According to Luka Renko (KOER), every platform is structured in line with the needs of the operator. The communication platforms are more or less standardized, but it depends on what one needs in the background and what kind of assets they drive.

Piloting a flexibility platform can take years

The two aggregators, KOER and Alteo, developed their platforms because they couldn’t find a ready-made solution on the market.

A platform must have the ability to communicate with any other solution and to integrate new types of power plants and customers, Magdolna Tokai (Alteo) added.

Elena Boškov Kovač (Blueprint Energy Solutions) recalled that her company has implemented flexibility platforms since 2019, at the dawn of the opening of the flexibility market in Europe, and added that pilot projects for them take a long time.

“They require an immense amount of data. There’s a multitude of different stakeholders that need to support this, unlock the data, provide data resources. Piloting is incredibly important, and it can take years,” she pointed out.

Luka Renko (KOER) added that it took his company three to four years to start working as an aggregator in Croatia.

The future is bright, but we need to work on it

Summarized, here are the messages of the session’s participants:

Bernard (NGEN): The end consumer will start acting as an active buyer.

Zarić (EMS): We see changes in the future.

Candellari (CyberGrid): Open the markets.

Tokai (Alteo): Give a chance to all market participants and types of production.

Renko (KOER): Digitalization will help.

Elena Boškov Kovač (Blueprint Energy Solutions) praised the companies that had their representatives at the panel for starting to develop solutions ahead of the market reform.

“It’s also a good message to the system of sometimes sleepy energy companies waiting for their proprietary vendors to offer them solutions,” Boškov Kovač stated.