The illuminated Parthenon on the Acropolis in Athens at night, overlaid with a glowing digital line graph symbolizing market data.

The Greek energy landscape is evolving. With the publication of regulation ΦΕΚ Β’ 1248 (ΥΠΕΝ/ΓΔΕ/28255/1143) in March 2025, an important foundation was laid for the integration of standalone Battery Energy Storage Systems (BESS) by regulating the process for their grid connection. This is a positive signal for manufacturers and investors. However, physical installation is only the first step on the path to profitability. The actual value creation takes place on the Hellenic Energy Exchange (HEnEx) – through arbitrage or the provision of ancillary services. This raises the crucial question: Who ensures that these technologically advanced systems can realize their market potential? This article delves deep into the structure of the Greek power market, clarifies who is eligible to participate in trading, and highlights the indispensable role of aggregators as a bridge between BESS facilities and the power exchange.

The Hellenic Energy Exchange (HEnEx) – The Playing Field for Energy Trading

As the Nominated Electricity Market Operator (NEMO), the Hellenic Energy Exchange (HEnEx) is the heart of the liberalized Greek electricity market. It operates the central trading platforms: the Day-Ahead Market (DAM) and the Intraday Market (IDM). Here, electricity volumes are traded on a short-term basis, and prices are formed transparently. These markets are crucial for the efficiency of the overall system and the integration of renewable energies. This is complemented by the Balancing Market, which is managed by the Transmission System Operator (IPTO) in close coordination with HEnEx and ensures grid stability. All these market segments are potentially relevant for BESS operators.

Who Can Trade? The Official Market Participants

Access to trading on HEnEx is clearly regulated and requires meeting specific criteria defined in Greek energy law (particularly L. 4001/2011) and the detailed HEnEx Rulebook. Eligible participants typically include:

  1. Power Producers: Companies licensed for power generation that feed energy into the grid.
  2. Electricity Suppliers: Licensed companies that sell electricity to end consumers.
  3. Traders: Companies with a trading license that buy and sell electricity, not necessarily having their own generation assets or end customers.
  4. Producers of Renewable Energy Sources (RES) and High-Efficiency Combined Heat and Power (HECHP): These often participate in the market via specific feed-in contracts or increasingly through aggregators.
  5. Aggregators: They bundle the capacities of smaller producers (like RES), flexible consumers, or storage facilities like BESS, representing them on the exchange.
  6. Large Industrial Customers/Direct Consumers: Under certain conditions, they can also gain direct market access.

Importantly, participation requires not only the appropriate license but also the technical prerequisites for communication with the trading platform, financial guarantees, and registration with the clearing house (EnExClear). Individuals do not trade directly but act as Certified Energy Traders on behalf of an authorized participating company.

Focus on BESS: From Grid Connection to Value Creation

The aforementioned regulation ΦΕΚ Β’ 1248 from March 2025 is highly significant for the BESS industry. It establishes, for the first time, a clear regulatory framework for the grid connection of standalone storage systems, thereby removing a major hurdle for their implementation in Greece.

However, grid connection is only the prerequisite. The actual revenue potential of BESS lies in their ability to market flexibility:

  • Energy Arbitrage: Buying and storing cheap electricity (e.g., during high RES production) to resell it at higher prices (e.g., during peak load times) on the Day-Ahead or Intraday Market.
  • Ancillary Services: Providing balancing energy for grid stabilization (e.g., Frequency Containment Reserve – FCR, automatic Frequency Restoration Reserve – aFRR) via the Balancing Market.

To tap into these revenue streams, BESS operators must actively participate in the relevant markets of HEnEx and/or the Balancing Market – a task requiring specific expertise.

The “Right Partner”: Why Aggregators are Crucial for BESS

This is where the “right partner” mentioned in the title comes into play: the aggregator. For many BESS operators, especially those new to the market or lacking an extensive in-house trading department, aggregators are the key to market success. Their role is multifaceted and essential:

  • Market Access & Interface: They provide the technical and procedural connection to HEnEx and the Balancing Market.
  • Bundling & Scaling: They pool the capacities of several smaller BESS units (or other flexible assets) to achieve relevant trading volumes and meet participation requirements.
  • Complexity Reduction: They handle the complex task of developing bidding strategies, nominating schedules, and communicating with market operators.
  • Balancing Responsibility: They integrate the BESS into their balancing group and assume responsibility for deviations between forecasted and actual injection/withdrawal.
  • Risk Management: They can help manage price and volume risks.
  • Expertise: They possess the necessary knowledge of the specific market rules for energy and ancillary services markets.

A well-known player in Greece is ΦΟΣΕ (Φορέας Σωρευτικής Εκπροσώπησης), which historically plays an important role in aggregating renewable energy (established by L. 4414/2016). However, the aggregation business is evolving, and it is expected that other aggregators, possibly specializing in BESS, will also establish themselves in the market. For BESS operators, choosing a competent aggregator is a strategic decision that significantly influences the investment’s profitability.

Market Context and Outlook

The opening of the Greek market to BESS, facilitated by regulations like ΦΕΚ Β’ 1248, and the established role of aggregators demonstrate a pathway for integrating new technologies into a liberalized market. This promotes competition and allows the provision of much-needed flexibility for integrating high shares of renewable energy.

The importance of BESS for grid stability and power system efficiency will continue to grow in Greece, as across Europe. Consequently, the significance of the players enabling market access for these technologies – primarily aggregators – also increases. The further development of market rules, particularly for ancillary services, will be crucial in determining how quickly and effectively the potential of BESS can be realized. Greece offers an exciting environment for investors and technology providers in this regard.

Conclusion

The Greek power market presents clear opportunities for Battery Energy Storage Systems, supported by regulatory steps such as simplified grid connection procedures. However, the key to realizing these opportunities lies not solely in the technology itself but in smart access to the revenue streams offered by HEnEx and the Balancing Market. For most BESS operators, this path leads through a partnership with an experienced aggregator. Understanding the market structure and choosing the right partner are therefore crucial for succeeding in the dynamic Greek energy market.

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