Greece is testing an electricity-market structure in which transmission and distribution system operators can procure services from the same pool of flexible consumers and distributed assets. The approach could create a second revenue layer for factories, commercial buildings and other controllable electricity users. The model is being demonstrated through the OPENTUNITY programme.
Under OPENTUNITY, transmission operator IPTO and distribution operator HEDNO tested coordinated flexibility procurement through the NODES marketplace under operating conditions. The September results are presented as a step beyond conventional demand response. Instead of flexibility being sold to a single electricity-market buyer, resources connected to the distribution system can potentially have value for both national and local networks.
Coordinating activations across network levels
The structure raises a commercial question over priority for the same flexible megawatt. A factory reducing electricity consumption by 2 MW could support IPTO balancing of the wider Greek system. If the factory is behind a distribution substation experiencing congestion, the same reduction may also be valuable to HEDNO at the same time.
Without coordination, IPTO and HEDNO could request conflicting actions or shift congestion from one network level to another. OPENTUNITY is testing mechanisms intended to prevent that outcome. The pilot provides both operators access to flexibility connected at distribution level while NODES coordinates procurement.
A dedicated coordination mechanism has been developed between HEDNO, IPTO and NODES to assess how activations affect both networks before flexibility is dispatched. The Greek pilot is described as an emerging example of a common flexibility market framework. In this setup, transmission balancing requirements and distribution congestion needs are managed through coordinated procurement.
Locational value for flexible demand and distributed assets
The business implications extend beyond system operation. Under a functioning flexibility market, industrial electricity users’ ability to increase or decrease consumption at specific times and locations becomes a separately tradeable service. The source material highlights that location affects economic value.
Two factories able to reduce consumption by identical amounts may have different values depending on whether one is behind a heavily loaded substation or connected to an unconstrained part of the network. Electricity flexibility therefore begins to acquire a locational price. The potential effect extends to aggregators building portfolios based not only on total flexible megawatts but also on where assets are connected.
The pilot includes portfolios of residential loads and distributed energy resources, showing how relatively small assets can be combined into a usable flexibility product. Controllable resources listed include industrial refrigeration, water heating, HVAC, pumping, distributed generation and EV charging. These assets could be aggregated and offered into local markets.
Rules for preventing double selling
For HEDNO, the potential attraction is linked to distribution constraints that occur during limited hours each year. Paying customers to temporarily alter consumption may sometimes be cheaper than replacing transformers, cables or other network infrastructure. In that context, flexibility is presented as an alternative to part of traditional grid CAPEX.
The source material connects the economics to uneven pressure on distribution networks from electrification, distributed solar, EV charging and new large loads. It also identifies a challenge in preventing the same resource from being sold twice. An aggregator cannot promise a factory’s 2-MW reduction to IPTO and separately guarantee the same 2 MW to HEDNO if both operators require it simultaneously.
A commercial market therefore needs clear rules covering availability, dispatch priority, baseline measurement, activation, verification and settlement. The coordination rules are described as potentially as important as underlying technology. The model also points to changes in how distribution operators participate in electricity markets.
DSO participation in short-duration services
Historically, DSOs primarily planned, maintained and reinforced networks. A local flexibility market turns them into buyers of short-duration electricity services. Instead of addressing every constraint through physical infrastructure build-outs, an operator can potentially procure temporary changes in customer behaviour.
This creates a market where aggregators, energy-service companies and software platforms operate alongside traditional equipment suppliers. It may also result in customers having several electricity relationships at once: one supplier providing electricity, an aggregator optimising load, IPTO valuing flexibility for system balancing and HEDNO valuing it for a local network constraint. Managing overlapping commercial relationships is identified as a next challenge.
Greece’s pilot remains a demonstration rather than a mature nationwide flexibility market. However, the September results indicate that the technical architecture for coordinated TSO-DSO procurement can work under operating conditions. As distributed resources multiply, the source material says the market will increasingly ask where flexible megawatts are located and which grid operator has the highest-value use at that moment.