In Solarplaza’s webinar “What’s the Deal with Merchant Standalone Batteries in Greece?”, Elena Kalogeropoulou, Energy Trader & Business Developer at Optimus Energy, offered key insights into how Battery Energy Storage Systems (BESS) can fully unlock their market potential in Greece. Drawing from Optimus Energy’s experience as the country’s leading market access provider and its strategic partnership with enspired, Europe’s top optimizer, she outlined the commercial, technical, and market factors shaping this fast-evolving sector.
Greece’s power system is undergoing a profound transformation. Renewables already dominate the country’s electricity generation mix, with more than half of the total demand met by clean sources and with more renewables expected to enter the market in the coming years, the majority of Greece’s electricity will soon be covered by renewable generation. Yet, this rapid renewable growth has brought significant challenges.
In the first half of 2025 alone, 1327 GWh of renewable generation, nearly 10% of total output, was curtailed, up sharply from 513 GWh the previous year. Curtailments have now become a daily occurrence in Optimus Energy’s trading activities, observed in real time across our portfolio and directly impacting renewable producers’ revenues. This surge in curtailments underscores an urgent need for flexibility solutions, where BESS are set to play a decisive role. “The increasing occurrence of negative prices is an opportunity, signaling that the system urgently needs flexibility, and BESS provide exactly that,” noted Elena.
Now, Greece stands out as one of Europe’s most attractive emerging markets for BESS, driven by three key structural factors. First, the country exhibits one of the widest Day-Ahead Market spreads in Europe, with near-zero or negative prices during midday oversupply from renewables, mainly due to high solar penetration and low demand, and peaks in the evening, creating ideal arbitrage opportunities for batteries. Second, the ancillary services market remains largely untapped and unsaturated, still offering high price spikes and limited competition, which presents a rare opportunity for early participants to secure significant revenue streams before the market reaches maturity. Third, Greece’s Transmission System Operator (TSO) maintains a relatively conservative balancing strategy that results in high-frequency and sizeable activations of flexibility services. This environment favors BESS assets, which can respond rapidly and efficiently to grid needs, thereby ensuring both enhanced system reliability and strong financial returns for investors.
Before large-scale batteries enter operation, Optimus Energy has already witnessed and demonstrated the value of flexibility through its Demand Response portfolio of industrial clients. After a year of active participation in the Balancing Market and Ancillary Services, Optimus Energy has achieved strong and consistent revenues from just the mFRR products, confirming the commercial viability of energy flexibility solutions in Greece. However, demand side is not fit to instantly respond to various price signals — and that’s precisely where batteries can unlock their full potential, offering real-time responsiveness and maximizing value for both the system and the market. “Frequent activations and measurable economic results demonstrate that flexibility is valuable and essential for the system,” Elena explained.
Operating a BESS asset in Greece, just like in more mature markets, will require a cross-market optimization strategy, integrating participation across all available segments and products. Elena presented an indicative 24-hour market operation profile illustrating how a BESS asset will soon be required to perform in Greece.
- Day-Ahead Auction – Setting the foundation for price arbitrage.
- Capacity Allocation (FCR, aFRR, mFRR) – Locking in additional ancillary services revenues.
- Intraday Trading (IDAs & Continuous XBID) – Continuously adjusting to updated forecasts, market signals and system needs.
- Real-Time Energy Delivery – Physical energy dispatch of the asset.
Each step relies on smart capacity allocation and algorithmic decision-making, processing thousands of variables to transform market fluctuations into optimized, data-driven control.
Optimus Energy complements its operational readiness and expertise offering a range of tailored commercial structures for BESS asset owners, designed to align with each investor’s risk appetite and financial objectives:
- Tolling Model: Provides guaranteed fixed revenue, making it ideal for investors seeking strong bankability and low-risk exposure.
- Floor & Profit-Sharing Model: Combines a guaranteed baseline with shared market upside.
- Fully Merchant Model: 100% exposure to market performance with shared profits.
Backed by a portfolio exceeding 4.5 GW, Optimus Energy leads Greece’s energy aggregation market. Through its partnership with enspired, the company will soon deliver real-time optimization and revenue maximization based on proven European performance. As Greece welcomes its first operational battery assets, Optimus Energy stands ready to bridge local market potential with international best practices.
Seize the opportunity to partner with Greece’s leading route-to-market provider, powered by Europe’s trusted optimizer.
Watch the full webinar here 👉 https://www.youtube.com/watch?v=wKPJKpv3WR0&t=2395s
