Metlen and Karatzis open Greece's largest standalone battery, 330 MW / 790 MWh in Thessaly
Victoria Shinder2 min readMETLEN and Karatzis Group of Companies inaugurated a standalone battery energy storage system in Larissa, Thessaly, on 14 October 2026, the two companies announced the next day. The plant has a power capacity of 330 MW and an energy capacity of 790 MWh. METLEN describes it as Greece's largest standalone storage facility, the largest in Eastern Europe and one of the largest in the European Union.
Ownership and roles. The project was delivered through a joint investment vehicle in which METLEN holds 49% and Karatzis Group 51%. METLEN built the facility and also handles its operation and maintenance, drawing, it says, on experience from other complex storage projects. The investment received loan support from the EU's Recovery and Resilience Facility (NextGenerationEU).
Why the government turned up. Prime Minister Kyriakos Mitsotakis and Environment and Energy Minister Stavros Papastavrou attended the ceremony. According to Energy-Storage.news, Mitsotakis said renewables had helped bring Greek energy prices down but needed to be accompanied by storage so that their output could be moved and used "where and when we need it". He added that the government had supported storage with Recovery Fund resources and was still channelling €200 million into similar interventions.
What the owners say it is for. METLEN's release presents the plant as a way to make the power system more flexible and resilient and to use renewable generation more efficiently, and argues that storage, grid works and interconnections are preconditions for attracting investment. Executive chairman Evangelos Mytilineos said storage, alongside grids and interconnections, is essential to use the clean energy Greece generates efficiently and to give businesses and consumers more reliable supply. Antonis Karatzis, chairman and chief executive of Karatzis Group, called it the start of an active role for the group in energy infrastructure with a long-term horizon.
Where it sits in the Greek market. Energy-Storage.news notes that the recovery-fund scheme was designed to start Greece's grid-scale storage market and that its first funded projects are now coming online at scale: refiner MORE completed three projects totalling 72 MW / 144 MWh earlier in the year. It also reports that large batteries can now be financed without the scheme, citing ContourGlobal's purchase of a merchant 100 MW / 400 MWh project at the start of 2026.
Source: METLEN press release, 15 October 2026 — https://www.metlen.com/news/press-releases/metlen-and-karatzis-group-inaugurate-greece-s-largest-standalone-battery-energy-storage-system-bess-in-thessaly/ ; Energy-Storage.news — https://www.energy-storage.news/greek-pm-says-storage-should-accompany-renewables-as-metlen-karatzis-inaugurate-790mwh-bess/