European regulators are preparing a new framework for measuring electricity-system flexibility, potentially accelerating the development of commercial markets in which industrial consumers, aggregators and distributed energy operators can earn revenue by changing when and how they use electricity.
The European Union Agency for the Cooperation of Energy Regulators, ACER, announced on October 21 that it would release a preliminary version of EU-Flex, an open-source electricity-market model designed to assess flexibility requirements across European power systems.
The consultation is scheduled to run from November 5 to December 17, 2026, ahead of the agency’s first EU-wide flexibility-needs assessment, planned for July 2027.
The immediate development is methodological rather than commercial. EU-Flex will not create an electricity trading platform, approve investments or guarantee payments to flexibility providers.
Its importance instead lies in creating a more transparent basis for determining which electricity systems require additional flexibility, how much is needed and where existing resources may be insufficient.
For Southeast European markets, this could help move flexibility from being primarily an operational requirement towards becoming a measurable, contractable and potentially financeable service.
From electricity consumption to electricity-market participation
Electricity markets have traditionally valued industrial consumers primarily according to the amount of electricity they purchase and the reliability of their demand.
The emerging model introduces another potential source of economic value: the ability of a consumer to change its electricity consumption in response to a verified market or system request.
A factory capable of reducing its electricity demand for a defined period could potentially offer that reduction as a service.
The same principle can apply to refrigeration facilities, heating systems, water-pumping stations and EV-charging operators that can shift selected activities without significantly affecting their core operations.
Instead of acting solely as an electricity customer, the facility becomes a potential provider of flexibility.
This does not mean that electricity demand becomes generation. Rather, the system can sometimes obtain an equivalent balancing response by reducing consumption instead of increasing production elsewhere.
The commercial case depends on whether the payment for flexibility outweighs the costs of operational disruption, additional equipment, administration and potential contractual liabilities.
Aggregators play a central role in this model.
By combining flexibility from multiple consumers, an aggregator can build a portfolio large enough to meet market participation requirements while providing a more consistent service than individual small facilities could offer independently.
The business model relies on digital controls, accurate metering, consumption baselines, dispatch instructions and settlement systems.
Romania demonstrates that demand response can deliver real balancing energy
The transition from regulation towards commercial operation is already becoming visible in Romania.
On September 1, 2026, transmission operator Transelectrica activated a balancing reserve group consisting entirely of controllable electricity demand.
The portfolio, organised by Romanian aggregator Flexumers, delivered a 3 MW demand reduction during a 30-minute activation on the manually activated frequency restoration reserve market.
The operation was significant because the reserve response did not come from a conventional generating plant or an electricity-storage facility.
Its underlying resource was the ability of electricity consumers to temporarily reduce their demand.
Romanian regulation establishes a 1 MW minimum participation threshold for relevant balancing services, allowing smaller consumers to participate collectively through aggregation.
The activation demonstrated that multiple consumption points could meet technical qualification requirements and respond to actual system-dispatch instructions.
Romania’s regulator, ANRE, separately approved a consumption-flexibility mechanism in August under which eligible consumers, suppliers and aggregators can offer voluntary demand reductions.
Under the mechanism, Transelectrica determines the required flexibility, participants submit price and quantity offers, and performance is verified through consumption measurements against established baselines.
Together, these developments provide evidence of an emerging market structure in which the demand side can participate directly in electricity-system operation.
They do not, however, establish the eventual size of the market, its annual turnover or the long-term profitability of flexibility providers.
Those outcomes will depend on activation frequency, procurement volumes, competing resources and the final remuneration framework.
ACER introduces a common framework for assessing investment needs
The new EU-Flex initiative follows ACER’s approval in July 2025 of a methodology for national electricity flexibility-needs assessments.
Under the EU electricity-market framework, Member States were required to prepare national assessments by July 2026 and are expected to establish indicative non-fossil flexibility objectives by January 2027.
The methodology distinguishes between system-wide flexibility requirements and flexibility needed to manage specific network constraints.
That distinction is particularly important for Southeast Europe, where the technical and commercial needs of individual electricity systems can vary significantly.
A country may require additional resources to manage rapid changes in national electricity demand, while a specific distribution area may need local demand reductions to prevent network congestion or infrastructure overload.
These different requirements imply different services, procurement mechanisms and contract structures.
A national shortage of flexibility does not automatically demonstrate that a particular privately developed asset will have a viable commercial market.
Investors need to understand whether the relevant system operator can purchase the service, whether the provider can qualify and what level of revenue could reasonably be expected.
EU-Flex could improve the transparency of these assessments by giving regulators and investors an open methodology against which assumptions can be tested.
Southeast Europe’s uneven market readiness creates opportunities
The regional market is developing at different speeds.
Romania now has an operating example of aggregated industrial demand participating in balancing services.
Croatia introduced an upgraded balancing platform in September 2026, changing the way reserve capacity and balancing energy are offered and creating conditions for broader flexible participation.
Bulgaria, by comparison, continues to face barriers linked to limited demand-response participation and relatively low smart-meter penetration.
The European Commission’s 2026 country assessment identified the limited development of Bulgarian demand response as an obstacle to more flexible electricity-market operation.
Serbia has already incorporated aggregation and independent-aggregator concepts into its energy legislation, including provisions allowing eligible customers to contract with independent aggregators.
Its regulator also consulted on supplier and aggregator switching procedures in August 2026.
For Serbian industrial consumers, the opportunity is to turn controllable production schedules, auxiliary processes and other flexible loads into potentially monetisable electricity services.
However, legislation alone does not create a fully functioning flexibility market.
Effective participation also requires technical qualification, reliable data exchange, settlement procedures and enforceable commercial arrangements.
Montenegro and other Western Balkan markets could examine similar structures as their electricity-market rules and digital infrastructure continue to develop.
Flexibility portfolios create a different financing proposition
For investors and lenders, aggregation creates an opportunity that differs substantially from conventional electricity generation.
An aggregator may own relatively little physical energy infrastructure.
Its principal investment may instead involve software, automation equipment, metering integration, customer acquisition and operational systems.
Revenues could come from reserve availability, actual dispatch, customer services or participation in other authorised flexibility mechanisms.
The resulting business therefore resembles a technology-enabled energy-services company more than a traditional power-plant operator.
The financing challenges are nevertheless significant.
Portfolio revenues depend on customer retention, verified response performance, regulatory access and the continued availability of market procurement.
A profitable business also requires clearly defined settlement arrangements between the aggregator, participating consumers, electricity suppliers and balance-responsible parties.
If a factory cannot reduce demand during a contracted activation, the aggregator could face penalties or replacement costs.
Revenue forecasts must therefore consider the reliability of the underlying industrial processes, rather than simply their theoretical flexibility.
A diversified portfolio can reduce dependence on individual customers, but it cannot eliminate wider risks affecting several customers at the same time.
Measuring demand could become as important as measuring generation
The decisive commercial requirement is reliable evidence of the flexibility actually delivered.
Metering systems, secure communications, operational records and independently verifiable consumption baselines determine whether a claimed reduction can be recognised as a legitimate market service.
Smart meters and industrial energy-management systems could therefore gain a direct revenue-generating role, extending their function beyond conventional billing and energy-efficiency monitoring.
The November consultation will give regulators, system operators and market participants an opportunity to examine how future EU-wide flexibility requirements should be modelled.
The strongest investment implications are likely to emerge later, when those assessed requirements are converted into procurement mechanisms, eligibility rules and actual revenue opportunities.
For Southeast Europe, Romania’s first operational demand-response activation provides the immediate commercial signal.
ACER’s new model provides the longer-term regulatory framework.
The opportunity is to connect the two: turn measurable industrial and distributed electricity flexibility into a reliable market service before traditional electricity companies capture the emerging customer relationships.
Fact basis: ACER’s October 21 announcement and national flexibility methodology; Romania’s ANRE regulatory decision and Flexumers activation; regional market and legislative developments.
