Greece has become one of the EU's most closely watched battery markets, and the reasons are visible in a single day's grid data. On 3 October, transmission system operator IPTO forecast a renewables peak of 12,723MW at noon against expected demand of less than 6,000MW — a surplus that only storage, interconnection or curtailment can absorb.

Policy ambition outrunning the grid

The policy response has been rapid. Greece passed its 2030 solar target of 13.5GW in summer 2026, and the government raised its 2030 storage goal to 5-7GW from 4.3GW. IPTO's draft ten-year development plan for 2027-2036 raises planned investment to €9 billion and aims to connect more than 10GW of new renewables by the mid-2030s.

The project pipeline is following. According to IPTO's plan, 1,403MW/4,439MWh of batteries hold connection terms, and more than 600MW are already operating. The average storage duration in the queue exceeds three hours.

The curtailment economics

Greece curtailed about 2TWh of renewable output in 2025. Researchers at Aristotle University of Thessaloniki expect 3.3-3.7TWh in 2026, and the price signal has deteriorated accordingly: Q1 2026 recorded 239.5 hours of zero or negative prices, versus 13 hours a year earlier.

That combination — rising curtailment and collapsing capture prices — is the fundamental driver of storage demand. Many Greek PV parks are expected to add batteries behind existing grid connections to reduce curtailment losses. Trading these hybrid parks is complex: optimisers must forecast solar output, manage shared connection limits, bid across markets and limit deviations monitored by IPTO.

Merchant, not subsidised

Greek Deputy Minister of Environment and Energy Nikos Tsafos has argued that unrestrained battery subsidies would repeat the costly solar support experience. Most new Greek storage is therefore expected to be merchant, with returns dependent on trading rather than support.

That makes the revenue stack decisive. Greek battery projects should treat current balancing capacity prices as temporary upside; the business case sits in Day-Ahead and Intraday trading plus aFRR and mFRR balancing energy. Finland offers a cautionary parallel — its first batteries earned much revenue from balancing capacity markets, but prices fell significantly as more capacity connected, shifting value toward energy trading and balancing energy.

Financing and the ownership cap

Capital remains the constraint. At a Thessaloniki industry seminar, it was reported that three of Greece's four systemic banks had declined to finance storage, citing a lack of local reference projects and concern that revenues may plateau after 2030.

Market structure adds a further layer: a 500MW cap means no group may own or control more than 500MW of storage, and since end-July the limit also counts capacity under management and aggregator agreements. At a 7GW target, that implies at least 14 accepted optimisers.

Aggregators are already positioning. Capalo AI received its RES aggregator licence from RAAEY in June and was registered by IPTO as a Balance Responsible Party and Balancing Service Provider on 12 October, with its first Greek asset a hybrid solar and storage park described as the first Article 11A hybrid park to be traded in Greece. In Bulgaria, the same firm increased PV capture price with BESS by 40-52% monthly between May and August — a data point Greek hybrid developers will be watching closely.

Source: energypress.eu

This article was assisted by AI analysis. Please refer to the original source for official information.