Metlen and Karatzis inaugurate 790 MWh BESS in Greece, supplied by Jinko ESS

Greek industrial and energy company Metlen, along with Greek industrial conglomerate Karatzis Group, have inaugurated a 330 MW / 790 MWh battery energy storage system (BESS) in Larissa, Thessaly, Greece. 

The project was officially inaugurated on October 14 in the presence of Greek prime minister Kyriakos Mitsotakis, minister of environment and energy Stavros Papastavrou, and representatives of local and national authorities.

The project was developed through a joint investment vehicle, with Karatzis Group holding a 51% stake and Metlen holding the remaining 49%. 

Metlen stated it was responsible for the construction, operation and maintenance of the facility, drawing on experience gained from energy storage projects across international markets. 

The project partners describe it as the country’s largest standalone battery storage project. While the announcements didn’t name Jinko ESS as the BESS supplier, ESS News has confirmation the project features the Chinese manufactuer’s SunTera G2 ESS.

Jinko previously published that it had supplied a 395 MW / 790 MWh system, matching the two-hour duration of the Thessaly BESS. The discrepancy is down to the project’s grid connection agreement with the Greek transmission system operator (ADMIE/IPTO), which capped output at 330 MW at the local high-voltage substation. The overbuild allows a roughly 1.2x DC-to-AC ratio.

The project’s grid connection agreement with the Greek transmission system operator (ADMIE/IPTO) in Larissa is capped at 330 MW of maximum active power injection at the high-voltage substation.

What they said

“I am particularly proud that today, here in Thessaly, we are inaugurating Greece’s largest standalone energy storage facility in Eastern Europe and one of the largest across the European Union,” said Evangelos Mytilineos, executive chairman of Metlen.

“I would like to thank our partners at Karatzis Group, Antonis Karatzis personally, and everyone at Metlen who contributed to the delivery of this landmark project.”

Speaking at the inauguration, Mitsotakis said energy storage would play a critical role in enabling greater use of renewable energy and highlighted the government’s ambition to have 3-4 GW of storage projects operating or under development by 2028.

In August 2026, Metlen signed a balance-of-plant contract with UK developer Pulse Clean Energy for the 129 MW / 362 MWh Penn BESS, located in West Midlands, England. 

Last month, Metlen agreed to sell the Tamarico II hybrid solar and battery project in Chile’s Atacama region to Copec subsidiary Copec Flux. The project comprises 165 MW of solar PV and 725 MWh of battery storage, with the potential to be expanded to 925 MWh.