European regulators are preparing a framework to measure flexibility in electricity systems, as commercial markets could allow industrial consumers, aggregators and distributed energy operators to earn revenue by changing how and when they use power. 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 for assessing European power systems’ flexibility requirements. A consultation is scheduled for November 5 to December 17, 2026, ahead of ACER’s first EU-wide flexibility-needs assessment, planned for July 2027.
EU-Flex is a methodological initiative, not a commercial platform. It will not create an electricity trading platform, authorise investments or guarantee payments to flexibility providers. The model is intended to provide a more transparent basis for determining which electricity systems need additional flexibility, how much they require and where existing resources are insufficient.
For Southeast European markets, the framework could support a shift towards treating flexibility as a service that can be measured, contracted and potentially financed. Electricity markets have traditionally valued industrial consumers for the power they purchase and the reliability of their demand. The emerging model adds potential economic value when consumers can change their consumption in response to a verified request.
Consumers can offer flexibility through changes in demand
A factory that can reduce its electricity use for a specified period may be able to offer that reduction as a service. Refrigeration facilities, heating systems, water pumping stations and EV charging operators may also be able to reschedule some operations without materially disrupting their main business. In this model, a facility can become a potential flexibility supplier rather than remaining only a passive electricity customer.
Demand reduction does not turn electricity consumption into generation. In some cases, the system can obtain an equivalent balancing response by reducing consumption instead of increasing production. The commercial benefit depends on whether the payment exceeds the costs of operational disruption, additional equipment and administration, as well as any contractual liabilities.
Aggregators can combine flexibility from multiple consumers into portfolios large enough to meet minimum market participation requirements. Such a portfolio can also offer a more dependable service than an individual small facility. The business model relies on digital controls, metering systems, consumption baselines, dispatch instructions and settlement arrangements.
Romania has activated aggregated demand for balancing
Romania provides an operating example of demand response delivering balancing energy. On September 1, 2026, transmission operator Transelectrica activated a balancing reserve group made up entirely of controllable electricity demand. Organised by Romanian aggregator Flexumers, the portfolio delivered a 3 MW demand reduction during a 30-minute activation on the manually activated frequency restoration reserve market.
The reserve did not rely on a generating plant or an electricity-storage installation; its resource was consumers’ ability to reduce consumption. Romanian regulation sets a 1 MW minimum participation threshold for relevant balancing services, enabling smaller consumers to participate collectively through aggregation. The activation showed that a group of consumption points could meet technical qualification requirements and respond to actual system-dispatch instructions.
Separately, Romania’s regulator ANRE approved a consumption-flexibility mechanism in August under which eligible consumers, suppliers and aggregators can offer voluntary demand reductions. Transelectrica assesses the flexibility required under the mechanism, participants submit price and quantity offers, and performance is verified by comparing consumption measurements with established baselines. Together, the two developments show an emerging structure for demand-side participation in system operation.
They do not establish the market’s eventual size, annual turnover or sustainable profitability. Those outcomes depend on activation frequency, procurement volumes, competing resources and remuneration rules.
ACER’s framework distinguishes system and network needs
EU-Flex 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 system-wide flexibility needs from flexibility required to manage network constraints.
The distinction matters in Southeast Europe, where national electricity systems have different technical and commercial requirements. A country may need additional resources to manage rapid changes in national electricity demand, while a particular distribution area may need local demand reductions to avoid infrastructure overloads. These different requirements call for different services, procurement arrangements and contract structures.
A national flexibility shortage does not by itself demonstrate demand for a particular privately developed asset. Investors need to establish whether the relevant system operator can purchase the service, whether a provider can qualify and what revenues could reasonably be expected. EU-Flex could make the underlying assessment more transparent and allow investors and regulators to test assumptions against an open methodology.
Regional market readiness varies across Southeast Europe
Romania now has an operating example of aggregated industrial demand participating in balancing services. Croatia introduced an upgraded balancing platform in September 2026, changing how reserve capacity and balancing energy are offered and creating conditions for more flexible participation. Bulgaria, meanwhile, continues to face barriers linked to limited demand-response participation and low smart-meter penetration.
The European Commission’s 2026 country assessment identified the limited development of demand response in Bulgaria as an obstacle to more flexible electricity-market operation. Serbia has incorporated aggregation and independent aggregator concepts into its energy legislation, including provisions that allow eligible customers to contract with independent aggregators. In August 2026, its regulator also consulted on procedures for switching suppliers and aggregators.
For Serbian industrial consumers, the opportunity is to turn controllable production schedules, auxiliary processes and other flexible loads into services that may eventually generate additional revenue. However, legislation alone does not constitute a fully operational market. Effective participation also requires technical qualification, data exchange, settlement rules and enforceable commercial arrangements.
Montenegro and other Western Balkan markets could examine comparable structures as their electricity-market rules and digital infrastructure develop.
Aggregation creates a distinct financing model
For investors and lenders, aggregation offers a proposition different from conventional electricity generation. An aggregator may own little physical energy infrastructure, with its main investment instead covering software, automation equipment, metering integration, customer acquisition and operational systems. Revenues may come from reserve availability, actual dispatch, customer services or contractual participation in other authorised flexibility mechanisms.
The resulting business is more like a technology-enabled energy-services company than a conventional power-plant operator. Lenders nevertheless face significant underwriting challenges: portfolio revenue depends on customer retention, verified response performance, regulatory access and continuity 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 may incur penalties or replacement costs. Revenue forecasts therefore need to reflect the reliability of the industrial processes involved, not just their theoretical flexibility. A diversified portfolio could reduce exposure to individual customers but cannot eliminate systematic risks affecting several customers at the same time.
Verified demand data underpins market participation
Reliable evidence of delivered flexibility is a key commercial requirement. Metering systems, secure communications, operational records and independently reviewable consumption baselines determine whether a claimed reduction can qualify as a recognised market service. Smart meters and industrial energy-management systems may therefore have revenue-generating functions beyond billing and efficiency monitoring.
The November consultation gives regulators, system operators and market participants an opportunity to examine how future EU-wide flexibility needs will be modelled. The investment implications are expected to emerge later, when assessed requirements are translated into procurement mechanisms, eligibility rules and revenues. Romania’s first operational demand-response activation provides an immediate commercial signal, while ACER’s model sets out a longer-term regulatory framework.
The stated opportunity is to connect these developments by turning measurable industrial and distributed electricity flexibility into a reliable market service before traditional electricity companies capture the emerging customer relationships.