Greece curtailed an estimated 1,905 GWh of renewable power in eight months. HELLENiQ ENERGY's new Thessaloniki battery could shift under 4% of that a year at one cycle a day

At some hours Greece now produces more solar and wind power than it uses, and part of that output is switched off.¹⁹ Green Tank, an independent, non-profit think tank,²² estimates that 1,905 GWh of renewable output was curtailed in Greece between January and August 2026, 8.1% of all renewable generation.⁹ Batteries, which store surplus power and release it later, are central to the government's plans.¹²¹³ On 8 October 2026 HELLENiQ ENERGY announced that the group's first battery park, at its industrial site in Thessaloniki, is in operation.¹¹⁶

What has HELLENiQ ENERGY built in Thessaloniki?

HELLENiQ Renewables, part of HELLENiQ ENERGY, has completed a 100 MW / 200 MWh battery storage system at the group's Thessaloniki industrial facilities.¹ΕΛ The park has three storage stations on about 100 stremmata (a Greek land unit of 1,000 m²), roughly 10 hectares by our calculation, and uses lithium iron phosphate (LFP) batteries with liquid cooling.¹²⁴ At 200 MWh and 100 MW it is a two-hour battery, by our calculation.¹ The total investment in the Thessaloniki park is about €50 million.¹²⁴

The park connects to the transmission grid through a new 33/150 kV step-up substation and an underground high-voltage line of about 5 km to the Thessaloniki extra-high-voltage centre (Κέντρο Υπερυψηλής Τάσης Θεσσαλονίκης, Kentro Yperypsilis Tasis Thessalonikis, ΚΥΤ).¹²⁴

How was it funded?

The project was selected in the first storage auction run by ΡΑΑΕΥ (Ρυθμιστική Αρχή Αποβλήτων, Ενέργειας και Υδάτων, Rythmistiki Archi Apovliton, Energeias kai Ydaton), Greece's regulator for waste, energy and water.¹²¹ ΡΑΑΕΥ launched that auction with decision Ε-45/2023, published in the Government Gazette (ΦΕΚ Β' 3939) on 17 June 2023.¹⁹ The auction offered investment aid of €200,000 per MW and awarded 411.79 MW to 12 projects in August 2023, including HELLENiQ's three Thessaloniki stations of 50 MW, 25 MW and 25 MW.⁶⁷⁸ The project is carried out under Greece's Recovery and Resilience Plan, "Greece 2.0", with European Union funding through NextGenerationEU.¹

Naftemporiki and BusinessVoice, reporting the same company briefing, put the Recovery Fund support at €20 million, as partial capital and operating aid.²³ That would be about 40% of the €50 million cost, by our calculation.¹² Both reports say energisation began on 1 October 2026 and the park is now in commercial operation.²³ Powergame describes October 2026 as a period of energisation and commissioning lasting about two to three weeks, so full commercial status is not yet clear.⁵

Is this Greece's first big battery?

No: HELLENiQ ENERGY's release calls the park the group's first battery storage project and "one of the largest" storage projects built in Greece and South-East Europe, in our translation.¹¹⁷ Greek headlines such as efsyn's call it HELLENiQ ENERGY's first "battery park", meaning the group's first, not Greece's.¹⁸¹ In July 2026 the Ministry of Environment and Energy, ΥΠΕΝ (Υπουργείο Περιβάλλοντος και Ενέργειας, Ypourgeio Perivallontos kai Energeias), said installed storage had risen from zero at the start of 2026 to 630 MW, according to two reports.¹²¹³ Green Tank counted 600.18 MW of stand-alone battery storage in operation in August 2026.¹⁰¹¹ The 100 MW Thessaloniki park adds about one-sixth to that, by our calculation.¹¹⁰

What does "3,000 electric cars a day" mean?

HELLENiQ ENERGY says the Thessaloniki park will run at least one full charge and discharge cycle a day, and that the energy stored corresponds to fully charging about 3,000 electric cars every day.¹ΕΛ Dividing 200 MWh by 3,000 gives about 67 kWh per car, a plausible large car battery, by our calculation.¹

Three caveats apply. The 3,000-car figure is a design comparison in the future tense, not measured output, and the park does not charge cars.¹ Less energy comes out of a battery than goes in: in August 2026 Greece's batteries absorbed 51.6 GWh and returned 44.9 GWh, according to Green Tank, about 87% by our calculation.¹⁰¹¹ And storing "more than 200 MWh" a day, in our translation, in a 200 MWh battery would take more than one cycle.¹

How much curtailment can one battery absorb?

ΑΔΜΗΕ (Ανεξάρτητος Διαχειριστής Μεταφοράς Ηλεκτρικής Ενέργειας, Anexartitos Diacheiristis Metaforas Ilektrikis Energeias) runs Greece's high-voltage transmission grid.²⁰ Green Tank's curtailment figures are its own estimates, built from ΑΔΜΗΕ's market-scheduling forecasts; we found no official 2026 total.⁹¹⁰ Green Tank estimates that batteries avoided 5% of curtailments in January to August 2026, and 15.4% in August 2026 alone.¹⁰¹¹

At one full cycle a day, the Thessaloniki park can shift at most about 73 GWh a year, by our calculation.¹ A full year of that would be under 4% of the 1,905 GWh Green Tank estimates was curtailed in the first eight months of 2026, by our calculation.¹⁹ The company says the park will reduce curtailment and provide flexibility and balancing services to the grid; how its time will be split between those uses is not public.¹

How many batteries does Greece plan by 2030?

ΥΠΕΝ's July 2026 plan, as reported, aims for batteries to reach about 1 GW by the end of 2026, 1.5 GW by mid-2027, 3 GW by 2028 and 6.8 GW by 2030.¹²¹³ Most of the 2030 total, 4.7 GW, is expected to come straight from the market rather than from subsidised auctions.¹²¹³

ΥΠΕΝ's 6.8 GW is higher than the 4.32 GW of batteries proposed in the 2024 draft of the National Energy and Climate Plan, ΕΣΕΚ (Εθνικό Σχέδιο για την Ενέργεια και το Κλίμα, Ethniko Schedio gia tin Energeia kai to Klima), by our comparison.¹²¹⁴¹⁵ That 2024 draft also proposed 1.74 GW of pumped hydro storage by 2030; we could not check the figures in the final, ratified plan.¹⁴¹⁵

Will the battery lower electricity bills?

No source we read gives any effect of the Thessaloniki park on household or business electricity prices.¹²³ At the briefing, HELLENiQ ENERGY's deputy chief executive, Giorgos Alexopoulos, made the general case: "Renewables cannot operate without batteries," in our translation.²³