Southeast Europe’s next major power-market entrant may not look like a traditional utility. It may own no turbine, dam, solar park or battery fleet. Instead, it could control software, customer contracts, telemetry and flexible consumption, giving it the ability to coordinate thousands of small production and consumption decisions. This is the emerging model of the independent aggregator, and its economics are becoming increasingly attractive as the region discovers that adding generation alone cannot solve its flexibility challenges.
ACER’s 2026 assessment of Southeast Europe highlights the lack of flexible resources during the evening solar ramp as a structural contributor to regional price stress, alongside cross-border transmission constraints. The diagnosis is shifting the focus from simply adding megawatts toward controlling when and how existing megawatts are used.
An aggregator combines flexible loads and distributed energy assets into a portfolio large enough to participate in electricity markets. The individual resources may be relatively ordinary: industrial pumps, refrigerated warehouses, HVAC systems, EV chargers, behind-the-meter batteries, backup generators or prosumer installations. Their value comes from coordination. A portfolio capable of reducing 20 MW of consumption within minutes, increasing demand during periods of oversupply or shifting several dozen megawatt-hours from evening to midday can compete with conventional balancing resources. Crucially, the aggregator does not need to finance all of the underlying assets; it monetises flexibility that already exists within the economy.
Where the market opens first
The regional opportunity is uneven. Greece already has dynamic retail pricing linked to smart-meter capabilities, making changes in customer consumption commercially visible. EU member states such as Romania, Bulgaria, Croatia, Slovenia and Hungary are becoming more deeply integrated into European balancing platforms and active-customer frameworks.
Serbia and other Energy Community markets are still translating high-level rights for active customers into practical rules governing market access, metering and settlement. That delay does not necessarily represent a disadvantage. It gives regulators an opportunity to adopt models already tested elsewhere while giving regional trading companies time to build customer portfolios before competition becomes more intense.
The first significant addressable market is likely to be industrial and commercial customers rather than households. A supermarket chain can coordinate hundreds of refrigeration systems, while a water utility can optimise pumping stations and reservoirs. A cement producer can shift selected auxiliary loads, a logistics company can schedule EV charging, and a data centre can adjust cooling and backup systems within clearly defined operating limits.
Individually, these sites may be too small or operationally complex to participate directly in electricity markets. Aggregation converts that fragmentation into scale. It also diversifies operational risk: while one customer may be temporarily unavailable, another can respond, allowing the aggregator to provide a more reliable flexibility product than any individual site could offer.
The commercial model
The revenue opportunity extends beyond balancing energy. A well-managed portfolio can reduce supplier imbalance exposure, optimise customer capacity charges, capture value from dynamic retail prices, participate in ancillary services and eventually provide local congestion-management services to distribution system operators.
That diversification is important because no single market will necessarily provide attractive returns for all assets at all times. The most resilient aggregator will therefore operate more like an asset manager, continuously allocating available flexibility to the highest-value opportunity while respecting customer operating constraints.
Contract design will be central to this model. Customers need clearly defined operating boundaries, including maximum activation frequency, minimum notice periods, temperature or pressure limits, battery state-of-charge floors and compensation mechanisms for interrupted production. At the same time, the aggregator needs reliable measurement and dispatch rights, while suppliers and balance-responsible parties need protection against uncoordinated deviations.
Revenue sharing can take several forms, including fixed payments, performance-based compensation or an arrangement embedded within a broader electricity-supply contract. In practice, the strongest commercial proposition may be one in which the customer never interacts with a balancing-market interface and simply receives a lower overall energy cost in exchange for providing controlled flexibility.
What could stop the model
The largest obstacles are likely to be regulatory and operational. Baseline methodologies must be credible; otherwise, markets risk paying for artificial reductions rather than genuine flexibility. Smart-meter data must also be accessible with customer consent, while prequalification rules should verify actual capabilities without imposing requirements designed exclusively for large conventional generators.
Balance responsibility must be clearly defined to prevent participants from being compensated twice for the same deviation. Cybersecurity will also become increasingly important because an aggregator’s platform could eventually control equipment across hundreds or thousands of sites.
Capital requirements are another underestimated challenge. Although an aggregator may own few physical assets, it can still face collateral requirements in wholesale and balancing markets, alongside technology-development and customer-acquisition costs. A small software company may therefore struggle to compete with utilities and established trading houses that already possess market access, credit lines and 24/7 dispatch capabilities.
For that reason, partnerships between software companies, electricity suppliers and industrial-service providers may offer the most realistic path to scale.
SEE outlook
The strategic implication is significant: ownership of generation will no longer be the only route to influence in electricity markets. A company controlling 500 MW of flexible demand could materially shape procurement and balancing positions without owning any of the underlying equipment.
As European balancing integration deepens through platforms such as MARI and PICASSO, flexible resources will increasingly be exposed to wider competition. That will make portfolio quality, availability and response speed increasingly important.
Southeast Europe’s flexibility market is therefore likely to develop in stages: industrial optimisation first, formal balancing-market participation second, followed by broader retail aggregation and local DSO services.
The company that builds the first large cross-border portfolio of flexible customers could ultimately become a regional power-market platform in its own right. In the next phase of Europe’s energy transition, the most valuable megawatt may not be the one a company owns on paper, but the one it can reliably switch on or off when the power system needs it.
