Battery Energy Storage Systems (BESS) in Greece are transitioning from early-stage pilots to critical infrastructure, driven by a rapidly maturing regulatory framework and increasing investor appetite. Multiple large-scale projects are now underway, providing a clearer view of which revenue models and financing structures are viable and likely to dominate over 2025–26.
Recent examples demonstrate this evolution. Elsewedy Electric’s 50 MW / 100 MWh standalone BESS in Oinofyta is financed through a €41.9 million package combining equity, a loan and grant from the EU’s Recovery and Resilience Facility (RRF), and bank financing from the National Bank of Greece. The project secured a 10-year Operational Support Agreement (a form of CfD) awarded via competitive auction under RAAEY and is expected to be commissioned by the end of 2025. Similarly, Faria Renewables’ 49.9 MW / 134 MWh system, due in Q3 2025, is supported by a €28 million loan from Attica Bank, developer equity, and EU funds. It was also selected through a competitive procedure, likely under comparable revenue and grant terms.
A notable contrast is the 330 MW / 790 MWh project by METLEN and Karatzis in Thessaly. This joint venture is proceeding without grants, tax reliefs or CfDs, relying instead on merchant revenues such as energy market arbitrage and grid services. With a €170 million capital outlay, it represents a shift towards unsubsidised business models, where financing leans more heavily on equity due to heightened risk exposure.
Auctions have played a key role in market development. Multiple rounds between 2023 and 2025 have awarded standalone BESS projects under 10-year CfDs and capex grants, offering developers predictable revenue and reducing upfront capital requirements. These contracts typically guarantee a €/MW-year payment for availability or operational readiness, with two-way settlement mechanisms. After the 10-year term, most projects are expected to rely on merchant market revenues.
Key long-term revenue sources for BESS in Greece include CfDs, capex subsidies, energy market arbitrage (buying low, selling high), participation in ancillary and balancing services (such as frequency control), and capacity or availability payments. Some projects, particularly those involving utilities like PPC in Western Macedonia, may also benefit from regulated revenues or strategic incentives linked to grid resilience or regional economic development.
Looking ahead, Greece is pivoting towards a merchant BESS model. A 4.7 GW programme announced for 2025–27 will offer priority grid access to projects without public subsidies or revenue guarantees. These merchant systems will depend entirely on market-based income streams and are expected to attract institutional capital willing to manage the associated risks. In response, the government is refining its regulatory framework—introducing clearer auction terms, performance guarantees, limits per bidder, and more rigorous technical and environmental permitting.
Financing structures in 2025–26 will reflect these shifts. Projects with CfDs and grants are expected to secure bank debt covering 50–70% of capital expenditure, with the remainder from developer equity or institutional partners. Merchant projects, lacking guaranteed cash flows, will rely more on equity—often through joint ventures or project finance with tighter covenants. Interest rates for debt are likely to remain in the mid-to-high single digits, depending on project risk, regulatory backing and hedging strategies. Inflation, interest rate volatility and supply chain constraints are pushing lenders and investors to demand more robust cost control, risk-sharing, and technical due diligence.
Equity investors—especially infrastructure funds and strategic players—will take on more merchant risk and play a larger role in structuring and de-risking projects. Joint ventures are increasingly common, as are strategies involving portfolio aggregation and exits post-commissioning. Some developers may look to sell operating BESS assets to institutional buyers once revenue performance is established.
As the sector matures, due diligence by both lenders and equity providers is tightening. Projects must demonstrate bankable forecasts for merchant revenues, resilience to electricity market volatility, and mitigation of operational risks such as battery degradation or delays in grid connection. Contractual frameworks will increasingly include performance guarantees, penalties for late commissioning, revenue-sharing mechanisms, and protection against regulatory or market changes.
In summary, the most likely financing model for a typical Greek BESS project in 2025–26 will combine a 10-year CfD (where available), one-off capex subsidies, 50–70% debt for auction-supported systems, and institutional equity, particularly for merchant deals. Beyond the CfD period, or for unsubsidised projects, developers will be fully exposed to market dynamics—requiring accurate forecasting, revenue stacking across energy, capacity and ancillary services, and increasingly sophisticated financial and technical risk management. As the regulatory environment stabilises and the market grows in scale and complexity, Greece is on track to become a leading European market for utility-scale battery storage.
